| // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! Lowers the AST to the HIR. |
| //! |
| //! Since the AST and HIR are fairly similar, this is mostly a simple procedure, |
| //! much like a fold. Where lowering involves a bit more work things get more |
| //! interesting and there are some invariants you should know about. These mostly |
| //! concern spans and ids. |
| //! |
| //! Spans are assigned to AST nodes during parsing and then are modified during |
| //! expansion to indicate the origin of a node and the process it went through |
| //! being expanded. Ids are assigned to AST nodes just before lowering. |
| //! |
| //! For the simpler lowering steps, ids and spans should be preserved. Unlike |
| //! expansion we do not preserve the process of lowering in the spans, so spans |
| //! should not be modified here. When creating a new node (as opposed to |
| //! 'folding' an existing one), then you create a new id using `next_id()`. |
| //! |
| //! You must ensure that ids are unique. That means that you should only use the |
| //! id from an AST node in a single HIR node (you can assume that AST node ids |
| //! are unique). Every new node must have a unique id. Avoid cloning HIR nodes. |
| //! If you do, you must then set the new node's id to a fresh one. |
| //! |
| //! Spans are used for error messages and for tools to map semantics back to |
| //! source code. It is therefore not as important with spans as ids to be strict |
| //! about use (you can't break the compiler by screwing up a span). Obviously, a |
| //! HIR node can only have a single span. But multiple nodes can have the same |
| //! span and spans don't need to be kept in order, etc. Where code is preserved |
| //! by lowering, it should have the same span as in the AST. Where HIR nodes are |
| //! new it is probably best to give a span for the whole AST node being lowered. |
| //! All nodes should have real spans, don't use dummy spans. Tools are likely to |
| //! get confused if the spans from leaf AST nodes occur in multiple places |
| //! in the HIR, especially for multiple identifiers. |
| |
| use dep_graph::DepGraph; |
| use hir; |
| use hir::HirVec; |
| use hir::map::{Definitions, DefKey, DefPathData}; |
| use hir::def_id::{DefIndex, DefId, CRATE_DEF_INDEX, DefIndexAddressSpace}; |
| use hir::def::{Def, PathResolution}; |
| use lint::builtin::PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES; |
| use middle::cstore::CrateStore; |
| use rustc_data_structures::indexed_vec::IndexVec; |
| use session::Session; |
| use util::common::FN_OUTPUT_NAME; |
| use util::nodemap::{DefIdMap, FxHashMap, NodeMap}; |
| |
| use std::collections::{BTreeMap, HashSet}; |
| use std::fmt::Debug; |
| use std::iter; |
| use std::mem; |
| use syntax::attr; |
| use syntax::ast::*; |
| use syntax::errors; |
| use syntax::ext::hygiene::{Mark, SyntaxContext}; |
| use syntax::print::pprust; |
| use syntax::ptr::P; |
| use syntax::codemap::{self, respan, Spanned, CompilerDesugaringKind}; |
| use syntax::std_inject; |
| use syntax::symbol::{Symbol, keywords}; |
| use syntax::tokenstream::{TokenStream, TokenTree, Delimited}; |
| use syntax::parse::token::Token; |
| use syntax::util::small_vector::SmallVector; |
| use syntax::visit::{self, Visitor}; |
| use syntax_pos::Span; |
| |
| const HIR_ID_COUNTER_LOCKED: u32 = 0xFFFFFFFF; |
| |
| pub struct LoweringContext<'a> { |
| crate_root: Option<&'static str>, |
| |
| // Use to assign ids to hir nodes that do not directly correspond to an ast node |
| sess: &'a Session, |
| |
| cstore: &'a CrateStore, |
| |
| // As we walk the AST we must keep track of the current 'parent' def id (in |
| // the form of a DefIndex) so that if we create a new node which introduces |
| // a definition, then we can properly create the def id. |
| parent_def: Option<DefIndex>, |
| resolver: &'a mut Resolver, |
| name_map: FxHashMap<Ident, Name>, |
| |
| /// The items being lowered are collected here. |
| items: BTreeMap<NodeId, hir::Item>, |
| |
| trait_items: BTreeMap<hir::TraitItemId, hir::TraitItem>, |
| impl_items: BTreeMap<hir::ImplItemId, hir::ImplItem>, |
| bodies: BTreeMap<hir::BodyId, hir::Body>, |
| exported_macros: Vec<hir::MacroDef>, |
| |
| trait_impls: BTreeMap<DefId, Vec<NodeId>>, |
| trait_auto_impl: BTreeMap<DefId, NodeId>, |
| |
| is_generator: bool, |
| |
| catch_scopes: Vec<NodeId>, |
| loop_scopes: Vec<NodeId>, |
| is_in_loop_condition: bool, |
| is_in_trait_impl: bool, |
| |
| // This is a list of in-band type definitions being generated by |
| // Argument-position `impl Trait`. |
| // When traversing a signature such as `fn foo(x: impl Trait)`, |
| // we record `impl Trait` as a new type parameter, then later |
| // add it on to `foo`s generics. |
| in_band_ty_params: Vec<hir::TyParam>, |
| |
| // Used to create lifetime definitions from in-band lifetime usages. |
| // e.g. `fn foo(x: &'x u8) -> &'x u8` to `fn foo<'x>(x: &'x u8) -> &'x u8` |
| // When a named lifetime is encountered in a function or impl header and |
| // has not been defined |
| // (i.e. it doesn't appear in the in_scope_lifetimes list), it is added |
| // to this list. The results of this list are then added to the list of |
| // lifetime definitions in the corresponding impl or function generics. |
| lifetimes_to_define: Vec<(Span, Name)>, |
| // Whether or not in-band lifetimes are being collected. This is used to |
| // indicate whether or not we're in a place where new lifetimes will result |
| // in in-band lifetime definitions, such a function or an impl header. |
| // This will always be false unless the `in_band_lifetimes` feature is |
| // enabled. |
| is_collecting_in_band_lifetimes: bool, |
| // Currently in-scope lifetimes defined in impl headers, fn headers, or HRTB. |
| // When `is_collectin_in_band_lifetimes` is true, each lifetime is checked |
| // against this list to see if it is already in-scope, or if a definition |
| // needs to be created for it. |
| in_scope_lifetimes: Vec<Name>, |
| |
| type_def_lifetime_params: DefIdMap<usize>, |
| |
| current_hir_id_owner: Vec<(DefIndex, u32)>, |
| item_local_id_counters: NodeMap<u32>, |
| node_id_to_hir_id: IndexVec<NodeId, hir::HirId>, |
| } |
| |
| pub trait Resolver { |
| /// Resolve a hir path generated by the lowerer when expanding `for`, `if let`, etc. |
| fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool); |
| |
| /// Obtain the resolution for a node id |
| fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution>; |
| |
| /// We must keep the set of definitions up to date as we add nodes that weren't in the AST. |
| /// This should only return `None` during testing. |
| fn definitions(&mut self) -> &mut Definitions; |
| } |
| |
| #[derive(Clone, Copy, Debug)] |
| enum ImplTraitContext { |
| /// Treat `impl Trait` as shorthand for a new universal generic parameter. |
| /// Example: `fn foo(x: impl Debug)`, where `impl Debug` is conceptually |
| /// equivalent to a fresh universal parameter like `fn foo<T: Debug>(x: T)`. |
| /// |
| /// We store a DefId here so we can look up necessary information later |
| Universal(DefId), |
| |
| /// Treat `impl Trait` as shorthand for a new universal existential parameter. |
| /// Example: `fn foo() -> impl Debug`, where `impl Debug` is conceptually |
| /// equivalent to a fresh existential parameter like `abstract type T; fn foo() -> T`. |
| Existential, |
| |
| /// `impl Trait` is not accepted in this position. |
| Disallowed, |
| } |
| |
| pub fn lower_crate(sess: &Session, |
| cstore: &CrateStore, |
| dep_graph: &DepGraph, |
| krate: &Crate, |
| resolver: &mut Resolver) |
| -> hir::Crate { |
| // We're constructing the HIR here; we don't care what we will |
| // read, since we haven't even constructed the *input* to |
| // incr. comp. yet. |
| dep_graph.assert_ignored(); |
| |
| LoweringContext { |
| crate_root: std_inject::injected_crate_name(), |
| sess, |
| cstore, |
| parent_def: None, |
| resolver, |
| name_map: FxHashMap(), |
| items: BTreeMap::new(), |
| trait_items: BTreeMap::new(), |
| impl_items: BTreeMap::new(), |
| bodies: BTreeMap::new(), |
| trait_impls: BTreeMap::new(), |
| trait_auto_impl: BTreeMap::new(), |
| exported_macros: Vec::new(), |
| catch_scopes: Vec::new(), |
| loop_scopes: Vec::new(), |
| is_in_loop_condition: false, |
| type_def_lifetime_params: DefIdMap(), |
| current_hir_id_owner: vec![(CRATE_DEF_INDEX, 0)], |
| item_local_id_counters: NodeMap(), |
| node_id_to_hir_id: IndexVec::new(), |
| is_generator: false, |
| is_in_trait_impl: false, |
| in_band_ty_params: Vec::new(), |
| lifetimes_to_define: Vec::new(), |
| is_collecting_in_band_lifetimes: false, |
| in_scope_lifetimes: Vec::new(), |
| }.lower_crate(krate) |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Eq)] |
| enum ParamMode { |
| /// Any path in a type context. |
| Explicit, |
| /// The `module::Type` in `module::Type::method` in an expression. |
| Optional |
| } |
| |
| struct LoweredNodeId { |
| node_id: NodeId, |
| hir_id: hir::HirId, |
| } |
| |
| enum ParenthesizedGenericArgs { |
| Ok, |
| Warn, |
| Err, |
| } |
| |
| impl<'a> LoweringContext<'a> { |
| fn lower_crate(mut self, c: &Crate) -> hir::Crate { |
| /// Full-crate AST visitor that inserts into a fresh |
| /// `LoweringContext` any information that may be |
| /// needed from arbitrary locations in the crate. |
| /// E.g. The number of lifetime generic parameters |
| /// declared for every type and trait definition. |
| struct MiscCollector<'lcx, 'interner: 'lcx> { |
| lctx: &'lcx mut LoweringContext<'interner>, |
| } |
| |
| impl<'lcx, 'interner> Visitor<'lcx> for MiscCollector<'lcx, 'interner> { |
| fn visit_item(&mut self, item: &'lcx Item) { |
| self.lctx.allocate_hir_id_counter(item.id, item); |
| |
| match item.node { |
| ItemKind::Struct(_, ref generics) | |
| ItemKind::Union(_, ref generics) | |
| ItemKind::Enum(_, ref generics) | |
| ItemKind::Ty(_, ref generics) | |
| ItemKind::Trait(_, _, ref generics, ..) => { |
| let def_id = self.lctx.resolver.definitions().local_def_id(item.id); |
| let count = generics.params.iter() |
| .filter(|param| param.is_lifetime_param()) |
| .count(); |
| self.lctx.type_def_lifetime_params.insert(def_id, count); |
| } |
| _ => {} |
| } |
| visit::walk_item(self, item); |
| } |
| |
| fn visit_trait_item(&mut self, item: &'lcx TraitItem) { |
| self.lctx.allocate_hir_id_counter(item.id, item); |
| visit::walk_trait_item(self, item); |
| } |
| |
| fn visit_impl_item(&mut self, item: &'lcx ImplItem) { |
| self.lctx.allocate_hir_id_counter(item.id, item); |
| visit::walk_impl_item(self, item); |
| } |
| } |
| |
| struct ItemLowerer<'lcx, 'interner: 'lcx> { |
| lctx: &'lcx mut LoweringContext<'interner>, |
| } |
| |
| impl<'lcx, 'interner> ItemLowerer<'lcx, 'interner> { |
| fn with_trait_impl_ref<F>(&mut self, trait_impl_ref: &Option<TraitRef>, f: F) |
| where F: FnOnce(&mut Self) |
| { |
| let old = self.lctx.is_in_trait_impl; |
| self.lctx.is_in_trait_impl = if let &None = trait_impl_ref { |
| false |
| } else { |
| true |
| }; |
| f(self); |
| self.lctx.is_in_trait_impl = old; |
| } |
| } |
| |
| impl<'lcx, 'interner> Visitor<'lcx> for ItemLowerer<'lcx, 'interner> { |
| fn visit_item(&mut self, item: &'lcx Item) { |
| let mut item_lowered = true; |
| self.lctx.with_hir_id_owner(item.id, |lctx| { |
| if let Some(hir_item) = lctx.lower_item(item) { |
| lctx.items.insert(item.id, hir_item); |
| } else { |
| item_lowered = false; |
| } |
| }); |
| |
| if item_lowered { |
| let item_lifetimes = match self.lctx.items.get(&item.id).unwrap().node { |
| hir::Item_::ItemImpl(_,_,_,ref generics,..) | |
| hir::Item_::ItemTrait(_,_,ref generics,..) => |
| generics.lifetimes().cloned().collect::<Vec<_>>(), |
| _ => Vec::new(), |
| }; |
| |
| self.lctx.with_parent_impl_lifetime_defs(&item_lifetimes, |this| { |
| let this = &mut ItemLowerer { lctx: this }; |
| if let ItemKind::Impl(_,_,_,_,ref opt_trait_ref,_,_) = item.node { |
| this.with_trait_impl_ref(opt_trait_ref, |this| { |
| visit::walk_item(this, item) |
| }); |
| } else { |
| visit::walk_item(this, item); |
| } |
| }); |
| } |
| } |
| |
| fn visit_trait_item(&mut self, item: &'lcx TraitItem) { |
| self.lctx.with_hir_id_owner(item.id, |lctx| { |
| let id = hir::TraitItemId { node_id: item.id }; |
| let hir_item = lctx.lower_trait_item(item); |
| lctx.trait_items.insert(id, hir_item); |
| }); |
| |
| visit::walk_trait_item(self, item); |
| } |
| |
| fn visit_impl_item(&mut self, item: &'lcx ImplItem) { |
| self.lctx.with_hir_id_owner(item.id, |lctx| { |
| let id = hir::ImplItemId { node_id: item.id }; |
| let hir_item = lctx.lower_impl_item(item); |
| lctx.impl_items.insert(id, hir_item); |
| }); |
| visit::walk_impl_item(self, item); |
| } |
| } |
| |
| self.lower_node_id(CRATE_NODE_ID); |
| debug_assert!(self.node_id_to_hir_id[CRATE_NODE_ID] == hir::CRATE_HIR_ID); |
| |
| visit::walk_crate(&mut MiscCollector { lctx: &mut self }, c); |
| visit::walk_crate(&mut ItemLowerer { lctx: &mut self }, c); |
| |
| let module = self.lower_mod(&c.module); |
| let attrs = self.lower_attrs(&c.attrs); |
| let body_ids = body_ids(&self.bodies); |
| |
| self.resolver |
| .definitions() |
| .init_node_id_to_hir_id_mapping(self.node_id_to_hir_id); |
| |
| hir::Crate { |
| module, |
| attrs, |
| span: c.span, |
| exported_macros: hir::HirVec::from(self.exported_macros), |
| items: self.items, |
| trait_items: self.trait_items, |
| impl_items: self.impl_items, |
| bodies: self.bodies, |
| body_ids, |
| trait_impls: self.trait_impls, |
| trait_auto_impl: self.trait_auto_impl, |
| } |
| } |
| |
| fn allocate_hir_id_counter<T: Debug>(&mut self, |
| owner: NodeId, |
| debug: &T) { |
| if self.item_local_id_counters.insert(owner, 0).is_some() { |
| bug!("Tried to allocate item_local_id_counter for {:?} twice", debug); |
| } |
| // Always allocate the first HirId for the owner itself |
| self.lower_node_id_with_owner(owner, owner); |
| } |
| |
| fn lower_node_id_generic<F>(&mut self, |
| ast_node_id: NodeId, |
| alloc_hir_id: F) |
| -> LoweredNodeId |
| where F: FnOnce(&mut Self) -> hir::HirId |
| { |
| if ast_node_id == DUMMY_NODE_ID { |
| return LoweredNodeId { |
| node_id: DUMMY_NODE_ID, |
| hir_id: hir::DUMMY_HIR_ID, |
| } |
| } |
| |
| let min_size = ast_node_id.as_usize() + 1; |
| |
| if min_size > self.node_id_to_hir_id.len() { |
| self.node_id_to_hir_id.resize(min_size, hir::DUMMY_HIR_ID); |
| } |
| |
| let existing_hir_id = self.node_id_to_hir_id[ast_node_id]; |
| |
| if existing_hir_id == hir::DUMMY_HIR_ID { |
| // Generate a new HirId |
| let hir_id = alloc_hir_id(self); |
| self.node_id_to_hir_id[ast_node_id] = hir_id; |
| LoweredNodeId { |
| node_id: ast_node_id, |
| hir_id, |
| } |
| } else { |
| LoweredNodeId { |
| node_id: ast_node_id, |
| hir_id: existing_hir_id, |
| } |
| } |
| } |
| |
| fn with_hir_id_owner<F>(&mut self, owner: NodeId, f: F) |
| where F: FnOnce(&mut Self) |
| { |
| let counter = self.item_local_id_counters |
| .insert(owner, HIR_ID_COUNTER_LOCKED) |
| .unwrap(); |
| let def_index = self.resolver.definitions().opt_def_index(owner).unwrap(); |
| self.current_hir_id_owner.push((def_index, counter)); |
| f(self); |
| let (new_def_index, new_counter) = self.current_hir_id_owner.pop().unwrap(); |
| |
| debug_assert!(def_index == new_def_index); |
| debug_assert!(new_counter >= counter); |
| |
| let prev = self.item_local_id_counters.insert(owner, new_counter).unwrap(); |
| debug_assert!(prev == HIR_ID_COUNTER_LOCKED); |
| } |
| |
| /// This method allocates a new HirId for the given NodeId and stores it in |
| /// the LoweringContext's NodeId => HirId map. |
| /// Take care not to call this method if the resulting HirId is then not |
| /// actually used in the HIR, as that would trigger an assertion in the |
| /// HirIdValidator later on, which makes sure that all NodeIds got mapped |
| /// properly. Calling the method twice with the same NodeId is fine though. |
| fn lower_node_id(&mut self, ast_node_id: NodeId) -> LoweredNodeId { |
| self.lower_node_id_generic(ast_node_id, |this| { |
| let &mut (def_index, ref mut local_id_counter) = this.current_hir_id_owner |
| .last_mut() |
| .unwrap(); |
| let local_id = *local_id_counter; |
| *local_id_counter += 1; |
| hir::HirId { |
| owner: def_index, |
| local_id: hir::ItemLocalId(local_id), |
| } |
| }) |
| } |
| |
| fn lower_node_id_with_owner(&mut self, |
| ast_node_id: NodeId, |
| owner: NodeId) |
| -> LoweredNodeId { |
| self.lower_node_id_generic(ast_node_id, |this| { |
| let local_id_counter = this.item_local_id_counters |
| .get_mut(&owner) |
| .unwrap(); |
| let local_id = *local_id_counter; |
| |
| // We want to be sure not to modify the counter in the map while it |
| // is also on the stack. Otherwise we'll get lost updates when writing |
| // back from the stack to the map. |
| debug_assert!(local_id != HIR_ID_COUNTER_LOCKED); |
| |
| *local_id_counter += 1; |
| let def_index = this.resolver.definitions().opt_def_index(owner).unwrap(); |
| |
| hir::HirId { |
| owner: def_index, |
| local_id: hir::ItemLocalId(local_id), |
| } |
| }) |
| } |
| |
| fn record_body(&mut self, value: hir::Expr, decl: Option<&FnDecl>) |
| -> hir::BodyId { |
| let body = hir::Body { |
| arguments: decl.map_or(hir_vec![], |decl| { |
| decl.inputs.iter().map(|x| self.lower_arg(x)).collect() |
| }), |
| is_generator: self.is_generator, |
| value, |
| }; |
| let id = body.id(); |
| self.bodies.insert(id, body); |
| id |
| } |
| |
| fn next_id(&mut self) -> LoweredNodeId { |
| self.lower_node_id(self.sess.next_node_id()) |
| } |
| |
| fn expect_full_def(&mut self, id: NodeId) -> Def { |
| self.resolver.get_resolution(id).map_or(Def::Err, |pr| { |
| if pr.unresolved_segments() != 0 { |
| bug!("path not fully resolved: {:?}", pr); |
| } |
| pr.base_def() |
| }) |
| } |
| |
| fn diagnostic(&self) -> &errors::Handler { |
| self.sess.diagnostic() |
| } |
| |
| fn str_to_ident(&self, s: &'static str) -> Name { |
| Symbol::gensym(s) |
| } |
| |
| fn allow_internal_unstable(&self, reason: CompilerDesugaringKind, span: Span) -> Span |
| { |
| let mark = Mark::fresh(Mark::root()); |
| mark.set_expn_info(codemap::ExpnInfo { |
| call_site: span, |
| callee: codemap::NameAndSpan { |
| format: codemap::CompilerDesugaring(reason), |
| span: Some(span), |
| allow_internal_unstable: true, |
| allow_internal_unsafe: false, |
| }, |
| }); |
| span.with_ctxt(SyntaxContext::empty().apply_mark(mark)) |
| } |
| |
| // Creates a new hir::GenericParam for every new lifetime and type parameter |
| // encountered while evaluating `f`. Definitions are created with the parent |
| // provided. If no `parent_id` is provided, no definitions will be returned. |
| fn collect_in_band_defs<T, F>( |
| &mut self, |
| parent_id: Option<DefId>, |
| f: F |
| ) -> (Vec<hir::GenericParam>, T) where F: FnOnce(&mut LoweringContext) -> T |
| { |
| assert!(!self.is_collecting_in_band_lifetimes); |
| assert!(self.lifetimes_to_define.is_empty()); |
| self.is_collecting_in_band_lifetimes = self.sess.features.borrow().in_band_lifetimes; |
| |
| assert!(self.in_band_ty_params.is_empty()); |
| |
| let res = f(self); |
| |
| self.is_collecting_in_band_lifetimes = false; |
| |
| let in_band_ty_params = self.in_band_ty_params.split_off(0); |
| let lifetimes_to_define = self.lifetimes_to_define.split_off(0); |
| |
| let mut params = match parent_id { |
| Some(parent_id) => lifetimes_to_define.into_iter().map(|(span, name)| { |
| let def_node_id = self.next_id().node_id; |
| |
| // Add a definition for the in-band lifetime def |
| self.resolver.definitions().create_def_with_parent( |
| parent_id.index, |
| def_node_id, |
| DefPathData::LifetimeDef(name.as_str()), |
| DefIndexAddressSpace::High, |
| Mark::root() |
| ); |
| |
| hir::GenericParam::Lifetime(hir::LifetimeDef { |
| lifetime: hir::Lifetime { |
| id: def_node_id, |
| span, |
| name: hir::LifetimeName::Name(name), |
| }, |
| bounds: Vec::new().into(), |
| pure_wrt_drop: false, |
| in_band: true, |
| }) |
| }).collect(), |
| None => Vec::new(), |
| }; |
| |
| params.extend(in_band_ty_params.into_iter().map(|tp| hir::GenericParam::Type(tp))); |
| |
| (params, res) |
| } |
| |
| // Evaluates `f` with the lifetimes in `lt_defs` in-scope. |
| // This is used to track which lifetimes have already been defined, and |
| // which are new in-band lifetimes that need to have a definition created |
| // for them. |
| fn with_in_scope_lifetime_defs<T, F>( |
| &mut self, |
| lt_defs: &[LifetimeDef], |
| f: F |
| ) -> T where F: FnOnce(&mut LoweringContext) -> T |
| { |
| let old_len = self.in_scope_lifetimes.len(); |
| let lt_def_names = lt_defs.iter().map(|lt_def| lt_def.lifetime.ident.name); |
| self.in_scope_lifetimes.extend(lt_def_names); |
| |
| let res = f(self); |
| |
| self.in_scope_lifetimes.truncate(old_len); |
| res |
| } |
| |
| // Same as the method above, but accepts `hir::LifetimeDef`s |
| // instead of `ast::LifetimeDef`s. |
| // This should only be used with generics that have already had their |
| // in-band lifetimes added. In practice, this means that this function is |
| // only used when lowering a child item of a trait or impl. |
| fn with_parent_impl_lifetime_defs<T, F>( |
| &mut self, |
| lt_defs: &[hir::LifetimeDef], |
| f: F |
| ) -> T where F: FnOnce(&mut LoweringContext) -> T |
| { |
| let old_len = self.in_scope_lifetimes.len(); |
| let lt_def_names = lt_defs.iter().map(|lt_def| lt_def.lifetime.name.name()); |
| self.in_scope_lifetimes.extend(lt_def_names); |
| |
| let res = f(self); |
| |
| self.in_scope_lifetimes.truncate(old_len); |
| res |
| } |
| |
| // Appends in-band lifetime defs and argument-position `impl Trait` defs |
| // to the existing set of generics. |
| fn add_in_band_defs<F, T>( |
| &mut self, |
| generics: &Generics, |
| parent_id: Option<DefId>, |
| f: F |
| ) -> (hir::Generics, T) |
| where F: FnOnce(&mut LoweringContext) -> T |
| { |
| let (in_band_defs, (mut lowered_generics, res)) = |
| self.with_in_scope_lifetime_defs( |
| &generics.params |
| .iter() |
| .filter_map(|p| match *p { |
| GenericParam::Lifetime(ref ld) => Some(ld.clone()), |
| _ => None, |
| }) |
| .collect::<Vec<_>>(), |
| |this| { |
| this.collect_in_band_defs(parent_id, |this| { |
| (this.lower_generics(generics), f(this)) |
| }) |
| } |
| ); |
| |
| lowered_generics.params = |
| lowered_generics.params.iter().cloned().chain(in_band_defs).collect(); |
| |
| (lowered_generics, res) |
| } |
| |
| fn with_catch_scope<T, F>(&mut self, catch_id: NodeId, f: F) -> T |
| where F: FnOnce(&mut LoweringContext) -> T |
| { |
| let len = self.catch_scopes.len(); |
| self.catch_scopes.push(catch_id); |
| |
| let result = f(self); |
| assert_eq!(len + 1, self.catch_scopes.len(), |
| "catch scopes should be added and removed in stack order"); |
| |
| self.catch_scopes.pop().unwrap(); |
| |
| result |
| } |
| |
| fn lower_body<F>(&mut self, decl: Option<&FnDecl>, f: F) -> hir::BodyId |
| where F: FnOnce(&mut LoweringContext) -> hir::Expr |
| { |
| let prev = mem::replace(&mut self.is_generator, false); |
| let result = f(self); |
| let r = self.record_body(result, decl); |
| self.is_generator = prev; |
| return r |
| } |
| |
| fn with_loop_scope<T, F>(&mut self, loop_id: NodeId, f: F) -> T |
| where F: FnOnce(&mut LoweringContext) -> T |
| { |
| // We're no longer in the base loop's condition; we're in another loop. |
| let was_in_loop_condition = self.is_in_loop_condition; |
| self.is_in_loop_condition = false; |
| |
| let len = self.loop_scopes.len(); |
| self.loop_scopes.push(loop_id); |
| |
| let result = f(self); |
| assert_eq!(len + 1, self.loop_scopes.len(), |
| "Loop scopes should be added and removed in stack order"); |
| |
| self.loop_scopes.pop().unwrap(); |
| |
| self.is_in_loop_condition = was_in_loop_condition; |
| |
| result |
| } |
| |
| fn with_loop_condition_scope<T, F>(&mut self, f: F) -> T |
| where F: FnOnce(&mut LoweringContext) -> T |
| { |
| let was_in_loop_condition = self.is_in_loop_condition; |
| self.is_in_loop_condition = true; |
| |
| let result = f(self); |
| |
| self.is_in_loop_condition = was_in_loop_condition; |
| |
| result |
| } |
| |
| fn with_new_scopes<T, F>(&mut self, f: F) -> T |
| where F: FnOnce(&mut LoweringContext) -> T |
| { |
| let was_in_loop_condition = self.is_in_loop_condition; |
| self.is_in_loop_condition = false; |
| |
| let catch_scopes = mem::replace(&mut self.catch_scopes, Vec::new()); |
| let loop_scopes = mem::replace(&mut self.loop_scopes, Vec::new()); |
| let result = f(self); |
| self.catch_scopes = catch_scopes; |
| self.loop_scopes = loop_scopes; |
| |
| self.is_in_loop_condition = was_in_loop_condition; |
| |
| result |
| } |
| |
| fn with_parent_def<T, F>(&mut self, parent_id: NodeId, f: F) -> T |
| where F: FnOnce(&mut LoweringContext) -> T |
| { |
| let old_def = self.parent_def; |
| self.parent_def = { |
| let defs = self.resolver.definitions(); |
| Some(defs.opt_def_index(parent_id).unwrap()) |
| }; |
| |
| let result = f(self); |
| |
| self.parent_def = old_def; |
| result |
| } |
| |
| fn def_key(&mut self, id: DefId) -> DefKey { |
| if id.is_local() { |
| self.resolver.definitions().def_key(id.index) |
| } else { |
| self.cstore.def_key(id) |
| } |
| } |
| |
| fn lower_ident(&mut self, ident: Ident) -> Name { |
| let ident = ident.modern(); |
| if ident.ctxt == SyntaxContext::empty() { |
| return ident.name; |
| } |
| *self.name_map.entry(ident).or_insert_with(|| Symbol::from_ident(ident)) |
| } |
| |
| fn lower_opt_sp_ident(&mut self, o_id: Option<Spanned<Ident>>) -> Option<Spanned<Name>> { |
| o_id.map(|sp_ident| respan(sp_ident.span, sp_ident.node.name)) |
| } |
| |
| fn lower_loop_destination(&mut self, destination: Option<(NodeId, Spanned<Ident>)>) |
| -> hir::Destination |
| { |
| match destination { |
| Some((id, label_ident)) => { |
| let target = if let Def::Label(loop_id) = self.expect_full_def(id) { |
| hir::LoopIdResult::Ok(self.lower_node_id(loop_id).node_id) |
| } else { |
| hir::LoopIdResult::Err(hir::LoopIdError::UnresolvedLabel) |
| }; |
| hir::Destination { |
| ident: Some(label_ident), |
| target_id: hir::ScopeTarget::Loop(target), |
| } |
| }, |
| None => { |
| let loop_id = self.loop_scopes |
| .last() |
| .map(|innermost_loop_id| *innermost_loop_id); |
| |
| hir::Destination { |
| ident: None, |
| target_id: hir::ScopeTarget::Loop( |
| loop_id.map(|id| Ok(self.lower_node_id(id).node_id)) |
| .unwrap_or(Err(hir::LoopIdError::OutsideLoopScope)) |
| .into()) |
| } |
| } |
| } |
| } |
| |
| fn lower_attrs(&mut self, attrs: &Vec<Attribute>) -> hir::HirVec<Attribute> { |
| attrs.iter().map(|a| self.lower_attr(a)).collect::<Vec<_>>().into() |
| } |
| |
| fn lower_attr(&mut self, attr: &Attribute) -> Attribute { |
| Attribute { |
| id: attr.id, |
| style: attr.style, |
| path: attr.path.clone(), |
| tokens: self.lower_token_stream(attr.tokens.clone()), |
| is_sugared_doc: attr.is_sugared_doc, |
| span: attr.span, |
| } |
| } |
| |
| fn lower_token_stream(&mut self, tokens: TokenStream) -> TokenStream { |
| tokens.into_trees() |
| .flat_map(|tree| self.lower_token_tree(tree).into_trees()) |
| .collect() |
| } |
| |
| fn lower_token_tree(&mut self, tree: TokenTree) -> TokenStream { |
| match tree { |
| TokenTree::Token(span, token) => { |
| self.lower_token(token, span) |
| } |
| TokenTree::Delimited(span, delimited) => { |
| TokenTree::Delimited(span, Delimited { |
| delim: delimited.delim, |
| tts: self.lower_token_stream(delimited.tts.into()).into(), |
| }).into() |
| } |
| } |
| } |
| |
| fn lower_token(&mut self, token: Token, span: Span) -> TokenStream { |
| match token { |
| Token::Interpolated(_) => {} |
| other => return TokenTree::Token(span, other).into(), |
| } |
| |
| let tts = token.interpolated_to_tokenstream(&self.sess.parse_sess, span); |
| self.lower_token_stream(tts) |
| } |
| |
| fn lower_arm(&mut self, arm: &Arm) -> hir::Arm { |
| hir::Arm { |
| attrs: self.lower_attrs(&arm.attrs), |
| pats: arm.pats.iter().map(|x| self.lower_pat(x)).collect(), |
| guard: arm.guard.as_ref().map(|ref x| P(self.lower_expr(x))), |
| body: P(self.lower_expr(&arm.body)), |
| } |
| } |
| |
| fn lower_ty_binding(&mut self, b: &TypeBinding, itctx: ImplTraitContext) -> hir::TypeBinding { |
| hir::TypeBinding { |
| id: self.lower_node_id(b.id).node_id, |
| name: self.lower_ident(b.ident), |
| ty: self.lower_ty(&b.ty, itctx), |
| span: b.span, |
| } |
| } |
| |
| fn lower_ty(&mut self, t: &Ty, itctx: ImplTraitContext) -> P<hir::Ty> { |
| let kind = match t.node { |
| TyKind::Infer => hir::TyInfer, |
| TyKind::Err => hir::TyErr, |
| TyKind::Slice(ref ty) => hir::TySlice(self.lower_ty(ty, itctx)), |
| TyKind::Ptr(ref mt) => hir::TyPtr(self.lower_mt(mt, itctx)), |
| TyKind::Rptr(ref region, ref mt) => { |
| let span = t.span.with_hi(t.span.lo()); |
| let lifetime = match *region { |
| Some(ref lt) => self.lower_lifetime(lt), |
| None => self.elided_lifetime(span) |
| }; |
| hir::TyRptr(lifetime, self.lower_mt(mt, itctx)) |
| } |
| TyKind::BareFn(ref f) => { |
| self.with_in_scope_lifetime_defs( |
| &f.generic_params |
| .iter() |
| .filter_map(|p| match *p { |
| GenericParam::Lifetime(ref ld) => Some(ld.clone()), |
| _ => None, |
| }) |
| .collect::<Vec<_>>(), |
| |this| hir::TyBareFn(P(hir::BareFnTy { |
| generic_params: this.lower_generic_params(&f.generic_params, &NodeMap()), |
| unsafety: this.lower_unsafety(f.unsafety), |
| abi: f.abi, |
| decl: this.lower_fn_decl(&f.decl, None, false), |
| arg_names: this.lower_fn_args_to_names(&f.decl), |
| }))) |
| } |
| TyKind::Never => hir::TyNever, |
| TyKind::Tup(ref tys) => { |
| hir::TyTup(tys.iter().map(|ty| self.lower_ty(ty, itctx)).collect()) |
| } |
| TyKind::Paren(ref ty) => { |
| return self.lower_ty(ty, itctx); |
| } |
| TyKind::Path(ref qself, ref path) => { |
| let id = self.lower_node_id(t.id); |
| let qpath = self.lower_qpath(t.id, qself, path, ParamMode::Explicit, itctx); |
| return self.ty_path(id, t.span, qpath); |
| } |
| TyKind::ImplicitSelf => { |
| hir::TyPath(hir::QPath::Resolved(None, P(hir::Path { |
| def: self.expect_full_def(t.id), |
| segments: hir_vec![ |
| hir::PathSegment::from_name(keywords::SelfType.name()) |
| ], |
| span: t.span, |
| }))) |
| } |
| TyKind::Array(ref ty, ref length) => { |
| let length = self.lower_body(None, |this| this.lower_expr(length)); |
| hir::TyArray(self.lower_ty(ty, itctx), length) |
| } |
| TyKind::Typeof(ref expr) => { |
| let expr = self.lower_body(None, |this| this.lower_expr(expr)); |
| hir::TyTypeof(expr) |
| } |
| TyKind::TraitObject(ref bounds, ..) => { |
| let mut lifetime_bound = None; |
| let bounds = bounds.iter().filter_map(|bound| { |
| match *bound { |
| TraitTyParamBound(ref ty, TraitBoundModifier::None) => { |
| Some(self.lower_poly_trait_ref(ty, itctx)) |
| } |
| TraitTyParamBound(_, TraitBoundModifier::Maybe) => None, |
| RegionTyParamBound(ref lifetime) => { |
| if lifetime_bound.is_none() { |
| lifetime_bound = Some(self.lower_lifetime(lifetime)); |
| } |
| None |
| } |
| } |
| }).collect(); |
| let lifetime_bound = lifetime_bound.unwrap_or_else(|| { |
| self.elided_lifetime(t.span) |
| }); |
| hir::TyTraitObject(bounds, lifetime_bound) |
| } |
| TyKind::ImplTrait(ref bounds) => { |
| use syntax::feature_gate::{emit_feature_err, GateIssue}; |
| let span = t.span; |
| match itctx { |
| ImplTraitContext::Existential => { |
| let has_feature = self.sess.features.borrow().conservative_impl_trait; |
| if !t.span.allows_unstable() && !has_feature { |
| emit_feature_err(&self.sess.parse_sess, "conservative_impl_trait", |
| t.span, GateIssue::Language, |
| "`impl Trait` in return position is experimental"); |
| } |
| let def_index = self.resolver.definitions().opt_def_index(t.id).unwrap(); |
| let hir_bounds = self.lower_bounds(bounds, itctx); |
| let (lifetimes, lifetime_defs) = |
| self.lifetimes_from_impl_trait_bounds(def_index, &hir_bounds); |
| |
| hir::TyImplTraitExistential(hir::ExistTy { |
| generics: hir::Generics { |
| params: lifetime_defs, |
| where_clause: hir::WhereClause { |
| id: self.next_id().node_id, |
| predicates: Vec::new().into(), |
| }, |
| span, |
| }, |
| bounds: hir_bounds, |
| }, lifetimes) |
| }, |
| ImplTraitContext::Universal(def_id) => { |
| let has_feature = self.sess.features.borrow().universal_impl_trait; |
| if !t.span.allows_unstable() && !has_feature { |
| emit_feature_err(&self.sess.parse_sess, "universal_impl_trait", |
| t.span, GateIssue::Language, |
| "`impl Trait` in argument position is experimental"); |
| } |
| |
| let def_node_id = self.next_id().node_id; |
| |
| // Add a definition for the in-band TyParam |
| let def_index = self.resolver.definitions().create_def_with_parent( |
| def_id.index, |
| def_node_id, |
| DefPathData::ImplTrait, |
| DefIndexAddressSpace::High, |
| Mark::root() |
| ); |
| |
| let hir_bounds = self.lower_bounds(bounds, itctx); |
| // Set the name to `impl Bound1 + Bound2` |
| let name = Symbol::intern(&pprust::ty_to_string(t)); |
| self.in_band_ty_params.push(hir::TyParam { |
| name, |
| id: def_node_id, |
| bounds: hir_bounds, |
| default: None, |
| span, |
| pure_wrt_drop: false, |
| synthetic: Some(hir::SyntheticTyParamKind::ImplTrait), |
| }); |
| |
| hir::TyPath(hir::QPath::Resolved(None, P(hir::Path { |
| span, |
| def: Def::TyParam(DefId::local(def_index)), |
| segments: hir_vec![hir::PathSegment::from_name(name)], |
| }))) |
| }, |
| ImplTraitContext::Disallowed => { |
| span_err!(self.sess, t.span, E0562, |
| "`impl Trait` not allowed outside of function \ |
| and inherent method return types"); |
| hir::TyErr |
| } |
| } |
| } |
| TyKind::Mac(_) => panic!("TyMac should have been expanded by now."), |
| }; |
| |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(t.id); |
| P(hir::Ty { |
| id: node_id, |
| node: kind, |
| span: t.span, |
| hir_id, |
| }) |
| } |
| |
| fn lifetimes_from_impl_trait_bounds( |
| &mut self, |
| parent_index: DefIndex, |
| bounds: &hir::TyParamBounds |
| ) -> (HirVec<hir::Lifetime>, HirVec<hir::GenericParam>) { |
| |
| // This visitor walks over impl trait bounds and creates defs for all lifetimes which |
| // appear in the bounds, excluding lifetimes that are created within the bounds. |
| // e.g. 'a, 'b, but not 'c in `impl for<'c> SomeTrait<'a, 'b, 'c>` |
| struct ImplTraitLifetimeCollector<'r, 'a: 'r> { |
| context: &'r mut LoweringContext<'a>, |
| parent: DefIndex, |
| collect_elided_lifetimes: bool, |
| currently_bound_lifetimes: Vec<hir::LifetimeName>, |
| already_defined_lifetimes: HashSet<hir::LifetimeName>, |
| output_lifetimes: Vec<hir::Lifetime>, |
| output_lifetime_params: Vec<hir::GenericParam>, |
| } |
| |
| impl<'r, 'a: 'r, 'v> hir::intravisit::Visitor<'v> for ImplTraitLifetimeCollector<'r, 'a> { |
| fn nested_visit_map<'this>(&'this mut self) |
| -> hir::intravisit::NestedVisitorMap<'this, 'v> { |
| hir::intravisit::NestedVisitorMap::None |
| } |
| |
| fn visit_path_parameters(&mut self, span: Span, parameters: &'v hir::PathParameters) { |
| // Don't collect elided lifetimes used inside of `Fn()` syntax. |
| if parameters.parenthesized { |
| let old_collect_elided_lifetimes = self.collect_elided_lifetimes; |
| self.collect_elided_lifetimes = false; |
| hir::intravisit::walk_path_parameters(self, span, parameters); |
| self.collect_elided_lifetimes = old_collect_elided_lifetimes; |
| } else { |
| hir::intravisit::walk_path_parameters(self, span, parameters); |
| } |
| } |
| |
| fn visit_ty(&mut self, t: &'v hir::Ty) { |
| // Don't collect elided lifetimes used inside of `fn()` syntax |
| if let &hir::Ty_::TyBareFn(_) = &t.node { |
| let old_collect_elided_lifetimes = self.collect_elided_lifetimes; |
| self.collect_elided_lifetimes = false; |
| hir::intravisit::walk_ty(self, t); |
| self.collect_elided_lifetimes = old_collect_elided_lifetimes; |
| } else { |
| hir::intravisit::walk_ty(self, t); |
| } |
| } |
| |
| fn visit_poly_trait_ref(&mut self, |
| polytr: &'v hir::PolyTraitRef, |
| _: hir::TraitBoundModifier) { |
| let old_len = self.currently_bound_lifetimes.len(); |
| |
| // Record the introduction of 'a in `for<'a> ...` |
| for param in &polytr.bound_generic_params { |
| if let hir::GenericParam::Lifetime(ref lt_def) = *param { |
| // Introduce lifetimes one at a time so that we can handle |
| // cases like `fn foo<'d>() -> impl for<'a, 'b: 'a, 'c: 'b + 'd>` |
| self.currently_bound_lifetimes.push(lt_def.lifetime.name); |
| |
| // Visit the lifetime bounds |
| for lt_bound in <_def.bounds { |
| self.visit_lifetime(<_bound); |
| } |
| } |
| } |
| |
| hir::intravisit::walk_trait_ref(self, &polytr.trait_ref); |
| |
| self.currently_bound_lifetimes.truncate(old_len); |
| } |
| |
| fn visit_lifetime(&mut self, lifetime: &'v hir::Lifetime) { |
| let name = match lifetime.name { |
| hir::LifetimeName::Implicit | |
| hir::LifetimeName::Underscore => |
| if self.collect_elided_lifetimes { |
| // Use `'_` for both implicit and underscore lifetimes in |
| // `abstract type Foo<'_>: SomeTrait<'_>;` |
| hir::LifetimeName::Underscore |
| } else { |
| return |
| } |
| name @ hir::LifetimeName::Name(_) => name, |
| hir::LifetimeName::Static => return, |
| }; |
| |
| if !self.currently_bound_lifetimes.contains(&name) && |
| !self.already_defined_lifetimes.contains(&name) |
| { |
| self.already_defined_lifetimes.insert(name); |
| |
| self.output_lifetimes.push(hir::Lifetime { |
| id: self.context.next_id().node_id, |
| span: lifetime.span, |
| name, |
| }); |
| |
| let def_node_id = self.context.next_id().node_id; |
| self.context.resolver.definitions().create_def_with_parent( |
| self.parent, |
| def_node_id, |
| DefPathData::LifetimeDef(name.name().as_str()), |
| DefIndexAddressSpace::High, |
| Mark::root() |
| ); |
| let def_lifetime = hir::Lifetime { |
| id: def_node_id, |
| span: lifetime.span, |
| name: name, |
| }; |
| self.output_lifetime_params.push(hir::GenericParam::Lifetime(hir::LifetimeDef { |
| lifetime: def_lifetime, |
| bounds: Vec::new().into(), |
| pure_wrt_drop: false, |
| in_band: false, |
| })); |
| } |
| } |
| } |
| |
| let mut lifetime_collector = ImplTraitLifetimeCollector { |
| context: self, |
| parent: parent_index, |
| collect_elided_lifetimes: true, |
| currently_bound_lifetimes: Vec::new(), |
| already_defined_lifetimes: HashSet::new(), |
| output_lifetimes: Vec::new(), |
| output_lifetime_params: Vec::new(), |
| }; |
| |
| for bound in bounds { |
| hir::intravisit::walk_ty_param_bound(&mut lifetime_collector, &bound); |
| } |
| |
| ( |
| lifetime_collector.output_lifetimes.into(), |
| lifetime_collector.output_lifetime_params.into() |
| ) |
| } |
| |
| fn lower_foreign_mod(&mut self, fm: &ForeignMod) -> hir::ForeignMod { |
| hir::ForeignMod { |
| abi: fm.abi, |
| items: fm.items.iter().map(|x| self.lower_foreign_item(x)).collect(), |
| } |
| } |
| |
| fn lower_global_asm(&mut self, ga: &GlobalAsm) -> P<hir::GlobalAsm> { |
| P(hir::GlobalAsm { |
| asm: ga.asm, |
| ctxt: ga.ctxt, |
| }) |
| } |
| |
| fn lower_variant(&mut self, v: &Variant) -> hir::Variant { |
| Spanned { |
| node: hir::Variant_ { |
| name: v.node.name.name, |
| attrs: self.lower_attrs(&v.node.attrs), |
| data: self.lower_variant_data(&v.node.data), |
| disr_expr: v.node.disr_expr.as_ref().map(|e| { |
| self.lower_body(None, |this| this.lower_expr(e)) |
| }), |
| }, |
| span: v.span, |
| } |
| } |
| |
| fn lower_qpath(&mut self, |
| id: NodeId, |
| qself: &Option<QSelf>, |
| p: &Path, |
| param_mode: ParamMode, |
| itctx: ImplTraitContext) |
| -> hir::QPath { |
| let qself_position = qself.as_ref().map(|q| q.position); |
| let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx)); |
| |
| let resolution = self.resolver.get_resolution(id) |
| .unwrap_or(PathResolution::new(Def::Err)); |
| |
| let proj_start = p.segments.len() - resolution.unresolved_segments(); |
| let path = P(hir::Path { |
| def: resolution.base_def(), |
| segments: p.segments[..proj_start].iter().enumerate().map(|(i, segment)| { |
| let param_mode = match (qself_position, param_mode) { |
| (Some(j), ParamMode::Optional) if i < j => { |
| // This segment is part of the trait path in a |
| // qualified path - one of `a`, `b` or `Trait` |
| // in `<X as a::b::Trait>::T::U::method`. |
| ParamMode::Explicit |
| } |
| _ => param_mode |
| }; |
| |
| // Figure out if this is a type/trait segment, |
| // which may need lifetime elision performed. |
| let parent_def_id = |this: &mut Self, def_id: DefId| { |
| DefId { |
| krate: def_id.krate, |
| index: this.def_key(def_id).parent.expect("missing parent") |
| } |
| }; |
| let type_def_id = match resolution.base_def() { |
| Def::AssociatedTy(def_id) if i + 2 == proj_start => { |
| Some(parent_def_id(self, def_id)) |
| } |
| Def::Variant(def_id) if i + 1 == proj_start => { |
| Some(parent_def_id(self, def_id)) |
| } |
| Def::Struct(def_id) | |
| Def::Union(def_id) | |
| Def::Enum(def_id) | |
| Def::TyAlias(def_id) | |
| Def::Trait(def_id) if i + 1 == proj_start => Some(def_id), |
| _ => None |
| }; |
| let parenthesized_generic_args = match resolution.base_def() { |
| // `a::b::Trait(Args)` |
| Def::Trait(..) if i + 1 == proj_start => ParenthesizedGenericArgs::Ok, |
| // `a::b::Trait(Args)::TraitItem` |
| Def::Method(..) | |
| Def::AssociatedConst(..) | |
| Def::AssociatedTy(..) if i + 2 == proj_start => ParenthesizedGenericArgs::Ok, |
| // Avoid duplicated errors |
| Def::Err => ParenthesizedGenericArgs::Ok, |
| // An error |
| Def::Struct(..) | Def::Enum(..) | Def::Union(..) | Def::TyAlias(..) | |
| Def::Variant(..) if i + 1 == proj_start => ParenthesizedGenericArgs::Err, |
| // A warning for now, for compatibility reasons |
| _ => ParenthesizedGenericArgs::Warn, |
| }; |
| |
| let num_lifetimes = type_def_id.map_or(0, |def_id| { |
| if let Some(&n) = self.type_def_lifetime_params.get(&def_id) { |
| return n; |
| } |
| assert!(!def_id.is_local()); |
| let n = self.cstore |
| .item_generics_cloned_untracked(def_id, self.sess) |
| .regions |
| .len(); |
| self.type_def_lifetime_params.insert(def_id, n); |
| n |
| }); |
| self.lower_path_segment(p.span, segment, param_mode, num_lifetimes, |
| parenthesized_generic_args, itctx) |
| }).collect(), |
| span: p.span, |
| }); |
| |
| // Simple case, either no projections, or only fully-qualified. |
| // E.g. `std::mem::size_of` or `<I as Iterator>::Item`. |
| if resolution.unresolved_segments() == 0 { |
| return hir::QPath::Resolved(qself, path); |
| } |
| |
| // Create the innermost type that we're projecting from. |
| let mut ty = if path.segments.is_empty() { |
| // If the base path is empty that means there exists a |
| // syntactical `Self`, e.g. `&i32` in `<&i32>::clone`. |
| qself.expect("missing QSelf for <T>::...") |
| } else { |
| // Otherwise, the base path is an implicit `Self` type path, |
| // e.g. `Vec` in `Vec::new` or `<I as Iterator>::Item` in |
| // `<I as Iterator>::Item::default`. |
| let new_id = self.next_id(); |
| self.ty_path(new_id, p.span, hir::QPath::Resolved(qself, path)) |
| }; |
| |
| // Anything after the base path are associated "extensions", |
| // out of which all but the last one are associated types, |
| // e.g. for `std::vec::Vec::<T>::IntoIter::Item::clone`: |
| // * base path is `std::vec::Vec<T>` |
| // * "extensions" are `IntoIter`, `Item` and `clone` |
| // * type nodes are: |
| // 1. `std::vec::Vec<T>` (created above) |
| // 2. `<std::vec::Vec<T>>::IntoIter` |
| // 3. `<<std::vec::Vec<T>>::IntoIter>::Item` |
| // * final path is `<<<std::vec::Vec<T>>::IntoIter>::Item>::clone` |
| for (i, segment) in p.segments.iter().enumerate().skip(proj_start) { |
| let segment = P(self.lower_path_segment(p.span, segment, param_mode, 0, |
| ParenthesizedGenericArgs::Warn, |
| itctx)); |
| let qpath = hir::QPath::TypeRelative(ty, segment); |
| |
| // It's finished, return the extension of the right node type. |
| if i == p.segments.len() - 1 { |
| return qpath; |
| } |
| |
| // Wrap the associated extension in another type node. |
| let new_id = self.next_id(); |
| ty = self.ty_path(new_id, p.span, qpath); |
| } |
| |
| // Should've returned in the for loop above. |
| span_bug!(p.span, "lower_qpath: no final extension segment in {}..{}", |
| proj_start, p.segments.len()) |
| } |
| |
| fn lower_path_extra(&mut self, |
| id: NodeId, |
| p: &Path, |
| name: Option<Name>, |
| param_mode: ParamMode, |
| defaults_to_global: bool) |
| -> hir::Path { |
| let mut segments = p.segments.iter(); |
| if defaults_to_global && p.is_global() { |
| segments.next(); |
| } |
| |
| hir::Path { |
| def: self.expect_full_def(id), |
| segments: segments.map(|segment| { |
| self.lower_path_segment(p.span, segment, param_mode, 0, |
| ParenthesizedGenericArgs::Err, |
| ImplTraitContext::Disallowed) |
| }).chain(name.map(|name| hir::PathSegment::from_name(name))) |
| .collect(), |
| span: p.span, |
| } |
| } |
| |
| fn lower_path(&mut self, |
| id: NodeId, |
| p: &Path, |
| param_mode: ParamMode, |
| defaults_to_global: bool) |
| -> hir::Path { |
| self.lower_path_extra(id, p, None, param_mode, defaults_to_global) |
| } |
| |
| fn lower_path_segment(&mut self, |
| path_span: Span, |
| segment: &PathSegment, |
| param_mode: ParamMode, |
| expected_lifetimes: usize, |
| parenthesized_generic_args: ParenthesizedGenericArgs, |
| itctx: ImplTraitContext) |
| -> hir::PathSegment { |
| let (mut parameters, infer_types) = if let Some(ref parameters) = segment.parameters { |
| let msg = "parenthesized parameters may only be used with a trait"; |
| match **parameters { |
| PathParameters::AngleBracketed(ref data) => { |
| self.lower_angle_bracketed_parameter_data(data, param_mode, itctx) |
| } |
| PathParameters::Parenthesized(ref data) => match parenthesized_generic_args { |
| ParenthesizedGenericArgs::Ok => |
| self.lower_parenthesized_parameter_data(data), |
| ParenthesizedGenericArgs::Warn => { |
| self.sess.buffer_lint(PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES, |
| CRATE_NODE_ID, data.span, msg.into()); |
| (hir::PathParameters::none(), true) |
| } |
| ParenthesizedGenericArgs::Err => { |
| struct_span_err!(self.sess, data.span, E0214, "{}", msg) |
| .span_label(data.span, "only traits may use parentheses").emit(); |
| (hir::PathParameters::none(), true) |
| } |
| } |
| } |
| } else { |
| self.lower_angle_bracketed_parameter_data(&Default::default(), param_mode, itctx) |
| }; |
| |
| if !parameters.parenthesized && parameters.lifetimes.is_empty() { |
| parameters.lifetimes = (0..expected_lifetimes).map(|_| { |
| self.elided_lifetime(path_span) |
| }).collect(); |
| } |
| |
| hir::PathSegment::new( |
| self.lower_ident(segment.identifier), |
| parameters, |
| infer_types |
| ) |
| } |
| |
| fn lower_angle_bracketed_parameter_data(&mut self, |
| data: &AngleBracketedParameterData, |
| param_mode: ParamMode, |
| itctx: ImplTraitContext) |
| -> (hir::PathParameters, bool) { |
| let &AngleBracketedParameterData { ref lifetimes, ref types, ref bindings, .. } = data; |
| (hir::PathParameters { |
| lifetimes: self.lower_lifetimes(lifetimes), |
| types: types.iter().map(|ty| self.lower_ty(ty, itctx)).collect(), |
| bindings: bindings.iter().map(|b| self.lower_ty_binding(b, itctx)).collect(), |
| parenthesized: false, |
| }, types.is_empty() && param_mode == ParamMode::Optional) |
| } |
| |
| fn lower_parenthesized_parameter_data(&mut self, |
| data: &ParenthesizedParameterData) |
| -> (hir::PathParameters, bool) { |
| const DISALLOWED: ImplTraitContext = ImplTraitContext::Disallowed; |
| let &ParenthesizedParameterData { ref inputs, ref output, span } = data; |
| let inputs = inputs.iter().map(|ty| self.lower_ty(ty, DISALLOWED)).collect(); |
| let mk_tup = |this: &mut Self, tys, span| { |
| let LoweredNodeId { node_id, hir_id } = this.next_id(); |
| P(hir::Ty { node: hir::TyTup(tys), id: node_id, hir_id, span }) |
| }; |
| |
| (hir::PathParameters { |
| lifetimes: hir::HirVec::new(), |
| types: hir_vec![mk_tup(self, inputs, span)], |
| bindings: hir_vec![hir::TypeBinding { |
| id: self.next_id().node_id, |
| name: Symbol::intern(FN_OUTPUT_NAME), |
| ty: output.as_ref().map(|ty| self.lower_ty(&ty, DISALLOWED)) |
| .unwrap_or_else(|| mk_tup(self, hir::HirVec::new(), span)), |
| span: output.as_ref().map_or(span, |ty| ty.span), |
| }], |
| parenthesized: true, |
| }, false) |
| } |
| |
| fn lower_local(&mut self, l: &Local) -> P<hir::Local> { |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(l.id); |
| P(hir::Local { |
| id: node_id, |
| hir_id, |
| ty: l.ty.as_ref().map(|t| self.lower_ty(t, ImplTraitContext::Disallowed)), |
| pat: self.lower_pat(&l.pat), |
| init: l.init.as_ref().map(|e| P(self.lower_expr(e))), |
| span: l.span, |
| attrs: l.attrs.clone(), |
| source: hir::LocalSource::Normal, |
| }) |
| } |
| |
| fn lower_mutability(&mut self, m: Mutability) -> hir::Mutability { |
| match m { |
| Mutability::Mutable => hir::MutMutable, |
| Mutability::Immutable => hir::MutImmutable, |
| } |
| } |
| |
| fn lower_arg(&mut self, arg: &Arg) -> hir::Arg { |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(arg.id); |
| hir::Arg { |
| id: node_id, |
| hir_id, |
| pat: self.lower_pat(&arg.pat), |
| } |
| } |
| |
| fn lower_fn_args_to_names(&mut self, decl: &FnDecl) |
| -> hir::HirVec<Spanned<Name>> { |
| decl.inputs.iter().map(|arg| { |
| match arg.pat.node { |
| PatKind::Ident(_, ident, None) => { |
| respan(ident.span, ident.node.name) |
| } |
| _ => respan(arg.pat.span, keywords::Invalid.name()), |
| } |
| }).collect() |
| } |
| |
| |
| fn lower_fn_decl(&mut self, |
| decl: &FnDecl, |
| fn_def_id: Option<DefId>, |
| impl_trait_return_allow: bool) |
| -> P<hir::FnDecl> { |
| // NOTE: The two last parameters here have to do with impl Trait. If fn_def_id is Some, |
| // then impl Trait arguments are lowered into generic parameters on the given |
| // fn_def_id, otherwise impl Trait is disallowed. (for now) |
| // |
| // Furthermore, if impl_trait_return_allow is true, then impl Trait may be used in |
| // return positions as well. This guards against trait declarations and their impls |
| // where impl Trait is disallowed. (again for now) |
| P(hir::FnDecl { |
| inputs: decl.inputs.iter() |
| .map(|arg| if let Some(def_id) = fn_def_id { |
| self.lower_ty(&arg.ty, ImplTraitContext::Universal(def_id)) |
| } else { |
| self.lower_ty(&arg.ty, ImplTraitContext::Disallowed) |
| }).collect(), |
| output: match decl.output { |
| FunctionRetTy::Ty(ref ty) => match fn_def_id { |
| Some(_) if impl_trait_return_allow => |
| hir::Return(self.lower_ty(ty, ImplTraitContext::Existential)), |
| _ => hir::Return(self.lower_ty(ty, ImplTraitContext::Disallowed)), |
| }, |
| FunctionRetTy::Default(span) => hir::DefaultReturn(span), |
| }, |
| variadic: decl.variadic, |
| has_implicit_self: decl.inputs.get(0).map_or(false, |arg| { |
| match arg.ty.node { |
| TyKind::ImplicitSelf => true, |
| TyKind::Rptr(_, ref mt) => mt.ty.node == TyKind::ImplicitSelf, |
| _ => false |
| } |
| }) |
| }) |
| } |
| |
| fn lower_ty_param_bound(&mut self, tpb: &TyParamBound, itctx: ImplTraitContext) |
| -> hir::TyParamBound { |
| match *tpb { |
| TraitTyParamBound(ref ty, modifier) => { |
| hir::TraitTyParamBound(self.lower_poly_trait_ref(ty, itctx), |
| self.lower_trait_bound_modifier(modifier)) |
| } |
| RegionTyParamBound(ref lifetime) => { |
| hir::RegionTyParamBound(self.lower_lifetime(lifetime)) |
| } |
| } |
| } |
| |
| fn lower_ty_param(&mut self, tp: &TyParam, add_bounds: &[TyParamBound]) -> hir::TyParam { |
| let mut name = self.lower_ident(tp.ident); |
| |
| // Don't expose `Self` (recovered "keyword used as ident" parse error). |
| // `rustc::ty` expects `Self` to be only used for a trait's `Self`. |
| // Instead, use gensym("Self") to create a distinct name that looks the same. |
| if name == keywords::SelfType.name() { |
| name = Symbol::gensym("Self"); |
| } |
| |
| let itctx = ImplTraitContext::Universal(self.resolver.definitions().local_def_id(tp.id)); |
| let mut bounds = self.lower_bounds(&tp.bounds, itctx); |
| if !add_bounds.is_empty() { |
| bounds = bounds.into_iter().chain( |
| self.lower_bounds(add_bounds, itctx).into_iter() |
| ).collect(); |
| } |
| |
| hir::TyParam { |
| id: self.lower_node_id(tp.id).node_id, |
| name, |
| bounds, |
| default: tp.default.as_ref().map(|x| self.lower_ty(x, ImplTraitContext::Disallowed)), |
| span: tp.span, |
| pure_wrt_drop: attr::contains_name(&tp.attrs, "may_dangle"), |
| synthetic: tp.attrs.iter() |
| .filter(|attr| attr.check_name("rustc_synthetic")) |
| .map(|_| hir::SyntheticTyParamKind::ImplTrait) |
| .nth(0), |
| } |
| } |
| |
| fn lower_lifetime(&mut self, l: &Lifetime) -> hir::Lifetime { |
| let name = match self.lower_ident(l.ident) { |
| x if x == "'_" => hir::LifetimeName::Underscore, |
| x if x == "'static" => hir::LifetimeName::Static, |
| name => { |
| if self.is_collecting_in_band_lifetimes && |
| !self.in_scope_lifetimes.contains(&name) && |
| self.lifetimes_to_define.iter() |
| .find(|&&(_, lt_name)| lt_name == name) |
| .is_none() |
| { |
| self.lifetimes_to_define.push((l.span, name)); |
| } |
| |
| hir::LifetimeName::Name(name) |
| } |
| }; |
| |
| hir::Lifetime { |
| id: self.lower_node_id(l.id).node_id, |
| name, |
| span: l.span, |
| } |
| } |
| |
| fn lower_lifetime_def(&mut self, l: &LifetimeDef) -> hir::LifetimeDef { |
| let was_collecting_in_band = self.is_collecting_in_band_lifetimes; |
| self.is_collecting_in_band_lifetimes = false; |
| |
| let def = hir::LifetimeDef { |
| lifetime: self.lower_lifetime(&l.lifetime), |
| bounds: self.lower_lifetimes(&l.bounds), |
| pure_wrt_drop: attr::contains_name(&l.attrs, "may_dangle"), |
| in_band: false, |
| }; |
| |
| self.is_collecting_in_band_lifetimes = was_collecting_in_band; |
| |
| def |
| } |
| |
| fn lower_lifetimes(&mut self, lts: &Vec<Lifetime>) -> hir::HirVec<hir::Lifetime> { |
| lts.iter().map(|l| self.lower_lifetime(l)).collect() |
| } |
| |
| fn lower_generic_params( |
| &mut self, |
| params: &Vec<GenericParam>, |
| add_bounds: &NodeMap<Vec<TyParamBound>>, |
| ) -> hir::HirVec<hir::GenericParam> { |
| params.iter() |
| .map(|param| match *param { |
| GenericParam::Lifetime(ref lifetime_def) => { |
| hir::GenericParam::Lifetime(self.lower_lifetime_def(lifetime_def)) |
| } |
| GenericParam::Type(ref ty_param) => { |
| hir::GenericParam::Type(self.lower_ty_param( |
| ty_param, |
| add_bounds.get(&ty_param.id).map_or(&[][..], |x| &x) |
| )) |
| } |
| }) |
| .collect() |
| } |
| |
| fn lower_generics(&mut self, g: &Generics) -> hir::Generics { |
| // Collect `?Trait` bounds in where clause and move them to parameter definitions. |
| // FIXME: This could probably be done with less rightward drift. Also looks like two control |
| // paths where report_error is called are also the only paths that advance to after |
| // the match statement, so the error reporting could probably just be moved there. |
| let mut add_bounds = NodeMap(); |
| for pred in &g.where_clause.predicates { |
| if let WherePredicate::BoundPredicate(ref bound_pred) = *pred { |
| 'next_bound: for bound in &bound_pred.bounds { |
| if let TraitTyParamBound(_, TraitBoundModifier::Maybe) = *bound { |
| let report_error = |this: &mut Self| { |
| this.diagnostic().span_err(bound_pred.bounded_ty.span, |
| "`?Trait` bounds are only permitted at the \ |
| point where a type parameter is declared"); |
| }; |
| // Check if the where clause type is a plain type parameter. |
| match bound_pred.bounded_ty.node { |
| TyKind::Path(None, ref path) |
| if path.segments.len() == 1 && |
| bound_pred.bound_generic_params.is_empty() => { |
| if let Some(Def::TyParam(def_id)) = |
| self.resolver.get_resolution(bound_pred.bounded_ty.id) |
| .map(|d| d.base_def()) { |
| if let Some(node_id) = |
| self.resolver.definitions().as_local_node_id(def_id) { |
| for param in &g.params { |
| if let GenericParam::Type(ref ty_param) = *param { |
| if node_id == ty_param.id { |
| add_bounds.entry(ty_param.id) |
| .or_insert(Vec::new()) |
| .push(bound.clone()); |
| continue 'next_bound; |
| } |
| } |
| } |
| } |
| } |
| report_error(self) |
| } |
| _ => report_error(self) |
| } |
| } |
| } |
| } |
| } |
| |
| hir::Generics { |
| params: self.lower_generic_params(&g.params, &add_bounds), |
| where_clause: self.lower_where_clause(&g.where_clause), |
| span: g.span, |
| } |
| } |
| |
| fn lower_where_clause(&mut self, wc: &WhereClause) -> hir::WhereClause { |
| hir::WhereClause { |
| id: self.lower_node_id(wc.id).node_id, |
| predicates: wc.predicates |
| .iter() |
| .map(|predicate| self.lower_where_predicate(predicate)) |
| .collect(), |
| } |
| } |
| |
| fn lower_where_predicate(&mut self, pred: &WherePredicate) -> hir::WherePredicate { |
| match *pred { |
| WherePredicate::BoundPredicate(WhereBoundPredicate{ ref bound_generic_params, |
| ref bounded_ty, |
| ref bounds, |
| span}) => { |
| self.with_in_scope_lifetime_defs( |
| &bound_generic_params.iter() |
| .filter_map(|p| match *p { |
| GenericParam::Lifetime(ref ld) => Some(ld.clone()), |
| _ => None, |
| }) |
| .collect::<Vec<_>>(), |
| |this| { |
| hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate { |
| bound_generic_params: |
| this.lower_generic_params(bound_generic_params, &NodeMap()), |
| bounded_ty: this.lower_ty(bounded_ty, ImplTraitContext::Disallowed), |
| bounds: bounds.iter().filter_map(|bound| match *bound { |
| // Ignore `?Trait` bounds. |
| // Tthey were copied into type parameters already. |
| TraitTyParamBound(_, TraitBoundModifier::Maybe) => None, |
| _ => Some(this.lower_ty_param_bound( |
| bound, ImplTraitContext::Disallowed)) |
| }).collect(), |
| span, |
| }) |
| } |
| ) |
| } |
| WherePredicate::RegionPredicate(WhereRegionPredicate{ ref lifetime, |
| ref bounds, |
| span}) => { |
| hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate { |
| span, |
| lifetime: self.lower_lifetime(lifetime), |
| bounds: bounds.iter().map(|bound| self.lower_lifetime(bound)).collect(), |
| }) |
| } |
| WherePredicate::EqPredicate(WhereEqPredicate{ id, |
| ref lhs_ty, |
| ref rhs_ty, |
| span}) => { |
| hir::WherePredicate::EqPredicate(hir::WhereEqPredicate { |
| id: self.lower_node_id(id).node_id, |
| lhs_ty: self.lower_ty(lhs_ty, ImplTraitContext::Disallowed), |
| rhs_ty: self.lower_ty(rhs_ty, ImplTraitContext::Disallowed), |
| span, |
| }) |
| } |
| } |
| } |
| |
| fn lower_variant_data(&mut self, vdata: &VariantData) -> hir::VariantData { |
| match *vdata { |
| VariantData::Struct(ref fields, id) => { |
| hir::VariantData::Struct(fields.iter() |
| .enumerate() |
| .map(|f| self.lower_struct_field(f)) |
| .collect(), |
| self.lower_node_id(id).node_id) |
| } |
| VariantData::Tuple(ref fields, id) => { |
| hir::VariantData::Tuple(fields.iter() |
| .enumerate() |
| .map(|f| self.lower_struct_field(f)) |
| .collect(), |
| self.lower_node_id(id).node_id) |
| } |
| VariantData::Unit(id) => hir::VariantData::Unit(self.lower_node_id(id).node_id), |
| } |
| } |
| |
| fn lower_trait_ref(&mut self, p: &TraitRef, itctx: ImplTraitContext) -> hir::TraitRef { |
| let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit, itctx) { |
| hir::QPath::Resolved(None, path) => path.and_then(|path| path), |
| qpath => bug!("lower_trait_ref: unexpected QPath `{:?}`", qpath) |
| }; |
| hir::TraitRef { |
| path, |
| ref_id: self.lower_node_id(p.ref_id).node_id, |
| } |
| } |
| |
| fn lower_poly_trait_ref(&mut self, |
| p: &PolyTraitRef, |
| itctx: ImplTraitContext) |
| -> hir::PolyTraitRef { |
| let bound_generic_params = self.lower_generic_params(&p.bound_generic_params, &NodeMap()); |
| let trait_ref = self.with_parent_impl_lifetime_defs( |
| &bound_generic_params.iter() |
| .filter_map(|p| match *p { |
| hir::GenericParam::Lifetime(ref ld) => Some(ld.clone()), |
| _ => None, |
| }) |
| .collect::<Vec<_>>(), |
| |this| this.lower_trait_ref(&p.trait_ref, itctx), |
| ); |
| |
| hir::PolyTraitRef { |
| bound_generic_params, |
| trait_ref, |
| span: p.span, |
| } |
| } |
| |
| fn lower_struct_field(&mut self, (index, f): (usize, &StructField)) -> hir::StructField { |
| hir::StructField { |
| span: f.span, |
| id: self.lower_node_id(f.id).node_id, |
| name: self.lower_ident(match f.ident { |
| Some(ident) => ident, |
| // FIXME(jseyfried) positional field hygiene |
| None => Ident { name: Symbol::intern(&index.to_string()), ctxt: f.span.ctxt() }, |
| }), |
| vis: self.lower_visibility(&f.vis, None), |
| ty: self.lower_ty(&f.ty, ImplTraitContext::Disallowed), |
| attrs: self.lower_attrs(&f.attrs), |
| } |
| } |
| |
| fn lower_field(&mut self, f: &Field) -> hir::Field { |
| hir::Field { |
| name: respan(f.ident.span, self.lower_ident(f.ident.node)), |
| expr: P(self.lower_expr(&f.expr)), |
| span: f.span, |
| is_shorthand: f.is_shorthand, |
| } |
| } |
| |
| fn lower_mt(&mut self, mt: &MutTy, itctx: ImplTraitContext) -> hir::MutTy { |
| hir::MutTy { |
| ty: self.lower_ty(&mt.ty, itctx), |
| mutbl: self.lower_mutability(mt.mutbl), |
| } |
| } |
| |
| fn lower_bounds(&mut self, bounds: &[TyParamBound], itctx: ImplTraitContext) |
| -> hir::TyParamBounds { |
| bounds.iter().map(|bound| self.lower_ty_param_bound(bound, itctx)).collect() |
| } |
| |
| fn lower_block(&mut self, b: &Block, targeted_by_break: bool) -> P<hir::Block> { |
| let mut expr = None; |
| |
| let mut stmts = vec![]; |
| |
| for (index, stmt) in b.stmts.iter().enumerate() { |
| if index == b.stmts.len() - 1 { |
| if let StmtKind::Expr(ref e) = stmt.node { |
| expr = Some(P(self.lower_expr(e))); |
| } else { |
| stmts.extend(self.lower_stmt(stmt)); |
| } |
| } else { |
| stmts.extend(self.lower_stmt(stmt)); |
| } |
| } |
| |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(b.id); |
| |
| P(hir::Block { |
| id: node_id, |
| hir_id, |
| stmts: stmts.into(), |
| expr, |
| rules: self.lower_block_check_mode(&b.rules), |
| span: b.span, |
| targeted_by_break, |
| recovered: b.recovered, |
| }) |
| } |
| |
| fn lower_item_kind(&mut self, |
| id: NodeId, |
| name: &mut Name, |
| attrs: &hir::HirVec<Attribute>, |
| vis: &mut hir::Visibility, |
| i: &ItemKind) |
| -> hir::Item_ { |
| match *i { |
| ItemKind::ExternCrate(string) => hir::ItemExternCrate(string), |
| ItemKind::Use(ref use_tree) => { |
| // Start with an empty prefix |
| let prefix = Path { |
| segments: vec![], |
| span: use_tree.span, |
| }; |
| |
| self.lower_use_tree(use_tree, &prefix, id, vis, name, attrs) |
| } |
| ItemKind::Static(ref t, m, ref e) => { |
| let value = self.lower_body(None, |this| this.lower_expr(e)); |
| hir::ItemStatic(self.lower_ty(t, ImplTraitContext::Disallowed), |
| self.lower_mutability(m), |
| value) |
| } |
| ItemKind::Const(ref t, ref e) => { |
| let value = self.lower_body(None, |this| this.lower_expr(e)); |
| hir::ItemConst(self.lower_ty(t, ImplTraitContext::Disallowed), value) |
| } |
| ItemKind::Fn(ref decl, unsafety, constness, abi, ref generics, ref body) => { |
| let fn_def_id = self.resolver.definitions().opt_local_def_id(id); |
| self.with_new_scopes(|this| { |
| let body_id = this.lower_body(Some(decl), |this| { |
| let body = this.lower_block(body, false); |
| this.expr_block(body, ThinVec::new()) |
| }); |
| let (generics, fn_decl) = |
| this.add_in_band_defs(generics, fn_def_id, |this| |
| this.lower_fn_decl(decl, fn_def_id, true)); |
| |
| hir::ItemFn(fn_decl, |
| this.lower_unsafety(unsafety), |
| this.lower_constness(constness), |
| abi, |
| generics, |
| body_id) |
| }) |
| } |
| ItemKind::Mod(ref m) => hir::ItemMod(self.lower_mod(m)), |
| ItemKind::ForeignMod(ref nm) => hir::ItemForeignMod(self.lower_foreign_mod(nm)), |
| ItemKind::GlobalAsm(ref ga) => hir::ItemGlobalAsm(self.lower_global_asm(ga)), |
| ItemKind::Ty(ref t, ref generics) => { |
| hir::ItemTy(self.lower_ty(t, ImplTraitContext::Disallowed), |
| self.lower_generics(generics)) |
| } |
| ItemKind::Enum(ref enum_definition, ref generics) => { |
| hir::ItemEnum(hir::EnumDef { |
| variants: enum_definition.variants |
| .iter() |
| .map(|x| self.lower_variant(x)) |
| .collect(), |
| }, |
| self.lower_generics(generics)) |
| } |
| ItemKind::Struct(ref struct_def, ref generics) => { |
| let struct_def = self.lower_variant_data(struct_def); |
| hir::ItemStruct(struct_def, self.lower_generics(generics)) |
| } |
| ItemKind::Union(ref vdata, ref generics) => { |
| let vdata = self.lower_variant_data(vdata); |
| hir::ItemUnion(vdata, self.lower_generics(generics)) |
| } |
| ItemKind::Impl(unsafety, |
| polarity, |
| defaultness, |
| ref ast_generics, |
| ref ifce, |
| ref ty, |
| ref impl_items) => { |
| let def_id = self.resolver.definitions().opt_local_def_id(id); |
| let (generics, (ifce, lowered_ty)) = |
| self.add_in_band_defs(ast_generics, def_id, |this| { |
| let ifce = ifce.as_ref().map(|trait_ref| { |
| this.lower_trait_ref(trait_ref, ImplTraitContext::Disallowed) |
| }); |
| |
| if let Some(ref trait_ref) = ifce { |
| if let Def::Trait(def_id) = trait_ref.path.def { |
| this.trait_impls.entry(def_id).or_insert(vec![]).push(id); |
| } |
| } |
| |
| let lowered_ty = this.lower_ty(ty, ImplTraitContext::Disallowed); |
| |
| (ifce, lowered_ty) |
| }); |
| |
| let new_impl_items = self.with_in_scope_lifetime_defs( |
| &ast_generics.params |
| .iter() |
| .filter_map(|p| match *p { |
| GenericParam::Lifetime(ref ld) => Some(ld.clone()), |
| _ => None, |
| }) |
| .collect::<Vec<_>>(), |
| |this| { |
| impl_items.iter() |
| .map(|item| this.lower_impl_item_ref(item)) |
| .collect() |
| } |
| ); |
| |
| |
| hir::ItemImpl(self.lower_unsafety(unsafety), |
| self.lower_impl_polarity(polarity), |
| self.lower_defaultness(defaultness, true /* [1] */), |
| generics, |
| ifce, |
| lowered_ty, |
| new_impl_items) |
| } |
| ItemKind::Trait(is_auto, unsafety, ref generics, ref bounds, ref items) => { |
| let bounds = self.lower_bounds(bounds, ImplTraitContext::Disallowed); |
| let items = items.iter().map(|item| self.lower_trait_item_ref(item)).collect(); |
| hir::ItemTrait(self.lower_is_auto(is_auto), |
| self.lower_unsafety(unsafety), |
| self.lower_generics(generics), |
| bounds, |
| items) |
| } |
| ItemKind::TraitAlias(ref generics, ref bounds) => { |
| hir::ItemTraitAlias(self.lower_generics(generics), |
| self.lower_bounds(bounds, ImplTraitContext::Disallowed)) |
| } |
| ItemKind::MacroDef(..) | ItemKind::Mac(..) => panic!("Shouldn't still be around"), |
| } |
| |
| // [1] `defaultness.has_value()` is never called for an `impl`, always `true` in order to |
| // not cause an assertion failure inside the `lower_defaultness` function |
| } |
| |
| fn lower_use_tree(&mut self, |
| tree: &UseTree, |
| prefix: &Path, |
| id: NodeId, |
| vis: &mut hir::Visibility, |
| name: &mut Name, |
| attrs: &hir::HirVec<Attribute>) |
| -> hir::Item_ { |
| let path = &tree.prefix; |
| |
| match tree.kind { |
| UseTreeKind::Simple(ident) => { |
| *name = ident.name; |
| |
| // First apply the prefix to the path |
| let mut path = Path { |
| segments: prefix.segments |
| .iter() |
| .chain(path.segments.iter()) |
| .cloned() |
| .collect(), |
| span: path.span |
| }; |
| |
| // Correctly resolve `self` imports |
| if path.segments.last().unwrap().identifier.name == keywords::SelfValue.name() { |
| let _ = path.segments.pop(); |
| if ident.name == keywords::SelfValue.name() { |
| *name = path.segments.last().unwrap().identifier.name; |
| } |
| } |
| |
| let path = P(self.lower_path(id, &path, ParamMode::Explicit, true)); |
| hir::ItemUse(path, hir::UseKind::Single) |
| } |
| UseTreeKind::Glob => { |
| let path = P(self.lower_path(id, &Path { |
| segments: prefix.segments |
| .iter() |
| .chain(path.segments.iter()) |
| .cloned() |
| .collect(), |
| span: path.span, |
| }, ParamMode::Explicit, true)); |
| hir::ItemUse(path, hir::UseKind::Glob) |
| } |
| UseTreeKind::Nested(ref trees) => { |
| let prefix = Path { |
| segments: prefix.segments |
| .iter() |
| .chain(path.segments.iter()) |
| .cloned() |
| .collect(), |
| span: prefix.span.to(path.span), |
| }; |
| |
| // Add all the nested PathListItems in the HIR |
| for &(ref use_tree, id) in trees { |
| self.allocate_hir_id_counter(id, &use_tree); |
| let LoweredNodeId { |
| node_id: new_id, |
| hir_id: new_hir_id, |
| } = self.lower_node_id(id); |
| |
| let mut vis = vis.clone(); |
| let mut name = name.clone(); |
| let item = self.lower_use_tree( |
| use_tree, &prefix, new_id, &mut vis, &mut name, &attrs, |
| ); |
| |
| self.with_hir_id_owner(new_id, |this| { |
| let vis = match vis { |
| hir::Visibility::Public => hir::Visibility::Public, |
| hir::Visibility::Crate => hir::Visibility::Crate, |
| hir::Visibility::Inherited => hir::Visibility::Inherited, |
| hir::Visibility::Restricted { ref path, id: _ } => { |
| hir::Visibility::Restricted { |
| path: path.clone(), |
| // We are allocating a new NodeId here |
| id: this.next_id().node_id, |
| } |
| } |
| }; |
| |
| this.items.insert(new_id, hir::Item { |
| id: new_id, |
| hir_id: new_hir_id, |
| name: name, |
| attrs: attrs.clone(), |
| node: item, |
| vis, |
| span: use_tree.span, |
| }); |
| }); |
| } |
| |
| // Privatize the degenerate import base, used only to check |
| // the stability of `use a::{};`, to avoid it showing up as |
| // a reexport by accident when `pub`, e.g. in documentation. |
| let path = P(self.lower_path(id, &prefix, ParamMode::Explicit, true)); |
| *vis = hir::Inherited; |
| hir::ItemUse(path, hir::UseKind::ListStem) |
| } |
| } |
| } |
| |
| fn lower_trait_item(&mut self, i: &TraitItem) -> hir::TraitItem { |
| self.with_parent_def(i.id, |this| { |
| let LoweredNodeId { node_id, hir_id } = this.lower_node_id(i.id); |
| let fn_def_id = this.resolver.definitions().opt_local_def_id(node_id); |
| |
| let (generics, node) = match i.node { |
| TraitItemKind::Const(ref ty, ref default) => { |
| ( |
| this.lower_generics(&i.generics), |
| hir::TraitItemKind::Const( |
| this.lower_ty(ty, ImplTraitContext::Disallowed), |
| default.as_ref().map(|x| { |
| this.lower_body(None, |this| this.lower_expr(x)) |
| })) |
| ) |
| } |
| TraitItemKind::Method(ref sig, None) => { |
| let names = this.lower_fn_args_to_names(&sig.decl); |
| this.add_in_band_defs(&i.generics, fn_def_id, |this| |
| hir::TraitItemKind::Method( |
| this.lower_method_sig(sig, fn_def_id, false), |
| hir::TraitMethod::Required(names))) |
| } |
| TraitItemKind::Method(ref sig, Some(ref body)) => { |
| let body_id = this.lower_body(Some(&sig.decl), |this| { |
| let body = this.lower_block(body, false); |
| this.expr_block(body, ThinVec::new()) |
| }); |
| |
| this.add_in_band_defs(&i.generics, fn_def_id, |this| |
| hir::TraitItemKind::Method( |
| this.lower_method_sig(sig, fn_def_id, false), |
| hir::TraitMethod::Provided(body_id))) |
| } |
| TraitItemKind::Type(ref bounds, ref default) => { |
| ( |
| this.lower_generics(&i.generics), |
| hir::TraitItemKind::Type( |
| this.lower_bounds(bounds, ImplTraitContext::Disallowed), |
| default.as_ref().map(|x| { |
| this.lower_ty(x, ImplTraitContext::Disallowed) |
| })) |
| ) |
| } |
| TraitItemKind::Macro(..) => panic!("Shouldn't exist any more"), |
| }; |
| |
| hir::TraitItem { |
| id: node_id, |
| hir_id, |
| name: this.lower_ident(i.ident), |
| attrs: this.lower_attrs(&i.attrs), |
| generics, |
| node, |
| span: i.span, |
| } |
| }) |
| } |
| |
| fn lower_trait_item_ref(&mut self, i: &TraitItem) -> hir::TraitItemRef { |
| let (kind, has_default) = match i.node { |
| TraitItemKind::Const(_, ref default) => { |
| (hir::AssociatedItemKind::Const, default.is_some()) |
| } |
| TraitItemKind::Type(_, ref default) => { |
| (hir::AssociatedItemKind::Type, default.is_some()) |
| } |
| TraitItemKind::Method(ref sig, ref default) => { |
| (hir::AssociatedItemKind::Method { |
| has_self: sig.decl.has_self(), |
| }, default.is_some()) |
| } |
| TraitItemKind::Macro(..) => unimplemented!(), |
| }; |
| hir::TraitItemRef { |
| id: hir::TraitItemId { node_id: i.id }, |
| name: self.lower_ident(i.ident), |
| span: i.span, |
| defaultness: self.lower_defaultness(Defaultness::Default, has_default), |
| kind, |
| } |
| } |
| |
| fn lower_impl_item(&mut self, i: &ImplItem) -> hir::ImplItem { |
| self.with_parent_def(i.id, |this| { |
| let LoweredNodeId { node_id, hir_id } = this.lower_node_id(i.id); |
| let fn_def_id = this.resolver.definitions().opt_local_def_id(node_id); |
| |
| let (generics, node) = match i.node { |
| ImplItemKind::Const(ref ty, ref expr) => { |
| let body_id = this.lower_body(None, |this| this.lower_expr(expr)); |
| ( |
| this.lower_generics(&i.generics), |
| hir::ImplItemKind::Const( |
| this.lower_ty(ty, ImplTraitContext::Disallowed), |
| body_id |
| ) |
| ) |
| } |
| ImplItemKind::Method(ref sig, ref body) => { |
| let body_id = this.lower_body(Some(&sig.decl), |this| { |
| let body = this.lower_block(body, false); |
| this.expr_block(body, ThinVec::new()) |
| }); |
| let impl_trait_return_allow = !this.is_in_trait_impl; |
| |
| this.add_in_band_defs(&i.generics, fn_def_id, |this| |
| hir::ImplItemKind::Method( |
| this.lower_method_sig(sig, fn_def_id, impl_trait_return_allow), |
| body_id)) |
| } |
| ImplItemKind::Type(ref ty) => ( |
| this.lower_generics(&i.generics), |
| hir::ImplItemKind::Type( |
| this.lower_ty(ty, ImplTraitContext::Disallowed)), |
| ), |
| ImplItemKind::Macro(..) => panic!("Shouldn't exist any more"), |
| }; |
| |
| hir::ImplItem { |
| id: node_id, |
| hir_id, |
| name: this.lower_ident(i.ident), |
| attrs: this.lower_attrs(&i.attrs), |
| generics, |
| vis: this.lower_visibility(&i.vis, None), |
| defaultness: this.lower_defaultness(i.defaultness, true /* [1] */), |
| node, |
| span: i.span, |
| } |
| }) |
| |
| // [1] since `default impl` is not yet implemented, this is always true in impls |
| } |
| |
| fn lower_impl_item_ref(&mut self, i: &ImplItem) -> hir::ImplItemRef { |
| hir::ImplItemRef { |
| id: hir::ImplItemId { node_id: i.id }, |
| name: self.lower_ident(i.ident), |
| span: i.span, |
| vis: self.lower_visibility(&i.vis, Some(i.id)), |
| defaultness: self.lower_defaultness(i.defaultness, true /* [1] */), |
| kind: match i.node { |
| ImplItemKind::Const(..) => hir::AssociatedItemKind::Const, |
| ImplItemKind::Type(..) => hir::AssociatedItemKind::Type, |
| ImplItemKind::Method(ref sig, _) => { |
| hir::AssociatedItemKind::Method { |
| has_self: sig.decl.has_self(), |
| } |
| }, |
| ImplItemKind::Macro(..) => unimplemented!(), |
| }, |
| } |
| |
| // [1] since `default impl` is not yet implemented, this is always true in impls |
| } |
| |
| fn lower_mod(&mut self, m: &Mod) -> hir::Mod { |
| hir::Mod { |
| inner: m.inner, |
| item_ids: m.items.iter().flat_map(|x| self.lower_item_id(x)).collect(), |
| } |
| } |
| |
| fn lower_item_id(&mut self, i: &Item) -> SmallVector<hir::ItemId> { |
| match i.node { |
| ItemKind::Use(ref use_tree) => { |
| let mut vec = SmallVector::one(hir::ItemId { id: i.id }); |
| self.lower_item_id_use_tree(use_tree, &mut vec); |
| return vec; |
| } |
| ItemKind::MacroDef(..) => return SmallVector::new(), |
| _ => {} |
| } |
| SmallVector::one(hir::ItemId { id: i.id }) |
| } |
| |
| fn lower_item_id_use_tree(&self, tree: &UseTree, vec: &mut SmallVector<hir::ItemId>) { |
| match tree.kind { |
| UseTreeKind::Nested(ref nested_vec) => { |
| for &(ref nested, id) in nested_vec { |
| vec.push(hir::ItemId { id, }); |
| self.lower_item_id_use_tree(nested, vec); |
| } |
| } |
| UseTreeKind::Glob => {} |
| UseTreeKind::Simple(..) => {} |
| } |
| } |
| |
| pub fn lower_item(&mut self, i: &Item) -> Option<hir::Item> { |
| let mut name = i.ident.name; |
| let mut vis = self.lower_visibility(&i.vis, None); |
| let attrs = self.lower_attrs(&i.attrs); |
| if let ItemKind::MacroDef(ref def) = i.node { |
| if !def.legacy || attr::contains_name(&i.attrs, "macro_export") { |
| let body = self.lower_token_stream(def.stream()); |
| self.exported_macros.push(hir::MacroDef { |
| name, |
| vis, |
| attrs, |
| id: i.id, |
| span: i.span, |
| body, |
| legacy: def.legacy, |
| }); |
| } |
| return None; |
| } |
| |
| let node = self.with_parent_def(i.id, |this| { |
| this.lower_item_kind(i.id, &mut name, &attrs, &mut vis, &i.node) |
| }); |
| |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(i.id); |
| |
| Some(hir::Item { |
| id: node_id, |
| hir_id, |
| name, |
| attrs, |
| node, |
| vis, |
| span: i.span, |
| }) |
| } |
| |
| fn lower_foreign_item(&mut self, i: &ForeignItem) -> hir::ForeignItem { |
| self.with_parent_def(i.id, |this| { |
| let node_id = this.lower_node_id(i.id).node_id; |
| let def_id = this.resolver.definitions().local_def_id(node_id); |
| hir::ForeignItem { |
| id: node_id, |
| name: i.ident.name, |
| attrs: this.lower_attrs(&i.attrs), |
| node: match i.node { |
| ForeignItemKind::Fn(ref fdec, ref generics) => { |
| // Disallow impl Trait in foreign items |
| let (generics, (fn_dec, fn_args)) = |
| this.add_in_band_defs( |
| generics, |
| Some(def_id), |
| |this| ( |
| this.lower_fn_decl(fdec, None, false), |
| this.lower_fn_args_to_names(fdec) |
| ) |
| ); |
| |
| hir::ForeignItemFn(fn_dec, fn_args, generics) |
| } |
| ForeignItemKind::Static(ref t, m) => { |
| hir::ForeignItemStatic(this.lower_ty(t, ImplTraitContext::Disallowed), m) |
| } |
| ForeignItemKind::Ty => { |
| hir::ForeignItemType |
| } |
| }, |
| vis: this.lower_visibility(&i.vis, None), |
| span: i.span, |
| } |
| }) |
| } |
| |
| fn lower_method_sig(&mut self, |
| sig: &MethodSig, |
| fn_def_id: Option<DefId>, |
| impl_trait_return_allow: bool) |
| -> hir::MethodSig { |
| hir::MethodSig { |
| abi: sig.abi, |
| unsafety: self.lower_unsafety(sig.unsafety), |
| constness: self.lower_constness(sig.constness), |
| decl: self.lower_fn_decl(&sig.decl, fn_def_id, impl_trait_return_allow), |
| } |
| } |
| |
| fn lower_is_auto(&mut self, a: IsAuto) -> hir::IsAuto { |
| match a { |
| IsAuto::Yes => hir::IsAuto::Yes, |
| IsAuto::No => hir::IsAuto::No, |
| } |
| } |
| |
| fn lower_unsafety(&mut self, u: Unsafety) -> hir::Unsafety { |
| match u { |
| Unsafety::Unsafe => hir::Unsafety::Unsafe, |
| Unsafety::Normal => hir::Unsafety::Normal, |
| } |
| } |
| |
| fn lower_constness(&mut self, c: Spanned<Constness>) -> hir::Constness { |
| match c.node { |
| Constness::Const => hir::Constness::Const, |
| Constness::NotConst => hir::Constness::NotConst, |
| } |
| } |
| |
| fn lower_unop(&mut self, u: UnOp) -> hir::UnOp { |
| match u { |
| UnOp::Deref => hir::UnDeref, |
| UnOp::Not => hir::UnNot, |
| UnOp::Neg => hir::UnNeg, |
| } |
| } |
| |
| fn lower_binop(&mut self, b: BinOp) -> hir::BinOp { |
| Spanned { |
| node: match b.node { |
| BinOpKind::Add => hir::BiAdd, |
| BinOpKind::Sub => hir::BiSub, |
| BinOpKind::Mul => hir::BiMul, |
| BinOpKind::Div => hir::BiDiv, |
| BinOpKind::Rem => hir::BiRem, |
| BinOpKind::And => hir::BiAnd, |
| BinOpKind::Or => hir::BiOr, |
| BinOpKind::BitXor => hir::BiBitXor, |
| BinOpKind::BitAnd => hir::BiBitAnd, |
| BinOpKind::BitOr => hir::BiBitOr, |
| BinOpKind::Shl => hir::BiShl, |
| BinOpKind::Shr => hir::BiShr, |
| BinOpKind::Eq => hir::BiEq, |
| BinOpKind::Lt => hir::BiLt, |
| BinOpKind::Le => hir::BiLe, |
| BinOpKind::Ne => hir::BiNe, |
| BinOpKind::Ge => hir::BiGe, |
| BinOpKind::Gt => hir::BiGt, |
| }, |
| span: b.span, |
| } |
| } |
| |
| fn lower_pat(&mut self, p: &Pat) -> P<hir::Pat> { |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(p.id); |
| |
| P(hir::Pat { |
| id: node_id, |
| hir_id, |
| node: match p.node { |
| PatKind::Wild => hir::PatKind::Wild, |
| PatKind::Ident(ref binding_mode, pth1, ref sub) => { |
| match self.resolver.get_resolution(p.id).map(|d| d.base_def()) { |
| // `None` can occur in body-less function signatures |
| def @ None | def @ Some(Def::Local(_)) => { |
| let canonical_id = match def { |
| Some(Def::Local(id)) => id, |
| _ => p.id |
| }; |
| hir::PatKind::Binding(self.lower_binding_mode(binding_mode), |
| canonical_id, |
| respan(pth1.span, pth1.node.name), |
| sub.as_ref().map(|x| self.lower_pat(x))) |
| } |
| Some(def) => { |
| hir::PatKind::Path(hir::QPath::Resolved(None, P(hir::Path { |
| span: pth1.span, |
| def, |
| segments: hir_vec![ |
| hir::PathSegment::from_name(pth1.node.name) |
| ], |
| }))) |
| } |
| } |
| } |
| PatKind::Lit(ref e) => hir::PatKind::Lit(P(self.lower_expr(e))), |
| PatKind::TupleStruct(ref path, ref pats, ddpos) => { |
| let qpath = self.lower_qpath(p.id, &None, path, ParamMode::Optional, |
| ImplTraitContext::Disallowed); |
| hir::PatKind::TupleStruct(qpath, |
| pats.iter().map(|x| self.lower_pat(x)).collect(), |
| ddpos) |
| } |
| PatKind::Path(ref qself, ref path) => { |
| hir::PatKind::Path(self.lower_qpath(p.id, qself, path, ParamMode::Optional, |
| ImplTraitContext::Disallowed)) |
| } |
| PatKind::Struct(ref path, ref fields, etc) => { |
| let qpath = self.lower_qpath(p.id, &None, path, ParamMode::Optional, |
| ImplTraitContext::Disallowed); |
| |
| let fs = fields.iter() |
| .map(|f| { |
| Spanned { |
| span: f.span, |
| node: hir::FieldPat { |
| name: self.lower_ident(f.node.ident), |
| pat: self.lower_pat(&f.node.pat), |
| is_shorthand: f.node.is_shorthand, |
| }, |
| } |
| }) |
| .collect(); |
| hir::PatKind::Struct(qpath, fs, etc) |
| } |
| PatKind::Tuple(ref elts, ddpos) => { |
| hir::PatKind::Tuple(elts.iter().map(|x| self.lower_pat(x)).collect(), ddpos) |
| } |
| PatKind::Box(ref inner) => hir::PatKind::Box(self.lower_pat(inner)), |
| PatKind::Ref(ref inner, mutbl) => { |
| hir::PatKind::Ref(self.lower_pat(inner), self.lower_mutability(mutbl)) |
| } |
| PatKind::Range(ref e1, ref e2, ref end) => { |
| hir::PatKind::Range(P(self.lower_expr(e1)), |
| P(self.lower_expr(e2)), |
| self.lower_range_end(end)) |
| } |
| PatKind::Slice(ref before, ref slice, ref after) => { |
| hir::PatKind::Slice(before.iter().map(|x| self.lower_pat(x)).collect(), |
| slice.as_ref().map(|x| self.lower_pat(x)), |
| after.iter().map(|x| self.lower_pat(x)).collect()) |
| } |
| PatKind::Mac(_) => panic!("Shouldn't exist here"), |
| }, |
| span: p.span, |
| }) |
| } |
| |
| fn lower_range_end(&mut self, e: &RangeEnd) -> hir::RangeEnd { |
| match *e { |
| RangeEnd::Included(_) => hir::RangeEnd::Included, |
| RangeEnd::Excluded => hir::RangeEnd::Excluded, |
| } |
| } |
| |
| fn lower_expr(&mut self, e: &Expr) -> hir::Expr { |
| let kind = match e.node { |
| // Issue #22181: |
| // Eventually a desugaring for `box EXPR` |
| // (similar to the desugaring above for `in PLACE BLOCK`) |
| // should go here, desugaring |
| // |
| // to: |
| // |
| // let mut place = BoxPlace::make_place(); |
| // let raw_place = Place::pointer(&mut place); |
| // let value = $value; |
| // unsafe { |
| // ::std::ptr::write(raw_place, value); |
| // Boxed::finalize(place) |
| // } |
| // |
| // But for now there are type-inference issues doing that. |
| ExprKind::Box(ref inner) => { |
| hir::ExprBox(P(self.lower_expr(inner))) |
| } |
| |
| // Desugar ExprBox: `in (PLACE) EXPR` |
| ExprKind::InPlace(ref placer, ref value_expr) => { |
| // to: |
| // |
| // let p = PLACE; |
| // let mut place = Placer::make_place(p); |
| // let raw_place = Place::pointer(&mut place); |
| // push_unsafe!({ |
| // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR )); |
| // InPlace::finalize(place) |
| // }) |
| let placer_expr = P(self.lower_expr(placer)); |
| let value_expr = P(self.lower_expr(value_expr)); |
| |
| let placer_ident = self.str_to_ident("placer"); |
| let place_ident = self.str_to_ident("place"); |
| let p_ptr_ident = self.str_to_ident("p_ptr"); |
| |
| let make_place = ["ops", "Placer", "make_place"]; |
| let place_pointer = ["ops", "Place", "pointer"]; |
| let move_val_init = ["intrinsics", "move_val_init"]; |
| let inplace_finalize = ["ops", "InPlace", "finalize"]; |
| |
| let unstable_span = |
| self.allow_internal_unstable(CompilerDesugaringKind::BackArrow, e.span); |
| let make_call = |this: &mut LoweringContext, p, args| { |
| let path = P(this.expr_std_path(unstable_span, p, ThinVec::new())); |
| P(this.expr_call(e.span, path, args)) |
| }; |
| |
| let mk_stmt_let = |this: &mut LoweringContext, bind, expr| { |
| this.stmt_let(e.span, false, bind, expr) |
| }; |
| |
| let mk_stmt_let_mut = |this: &mut LoweringContext, bind, expr| { |
| this.stmt_let(e.span, true, bind, expr) |
| }; |
| |
| // let placer = <placer_expr> ; |
| let (s1, placer_binding) = { |
| mk_stmt_let(self, placer_ident, placer_expr) |
| }; |
| |
| // let mut place = Placer::make_place(placer); |
| let (s2, place_binding) = { |
| let placer = self.expr_ident(e.span, placer_ident, placer_binding); |
| let call = make_call(self, &make_place, hir_vec![placer]); |
| mk_stmt_let_mut(self, place_ident, call) |
| }; |
| |
| // let p_ptr = Place::pointer(&mut place); |
| let (s3, p_ptr_binding) = { |
| let agent = P(self.expr_ident(e.span, place_ident, place_binding)); |
| let args = hir_vec![self.expr_mut_addr_of(e.span, agent)]; |
| let call = make_call(self, &place_pointer, args); |
| mk_stmt_let(self, p_ptr_ident, call) |
| }; |
| |
| // pop_unsafe!(EXPR)); |
| let pop_unsafe_expr = { |
| self.signal_block_expr(hir_vec![], |
| value_expr, |
| e.span, |
| hir::PopUnsafeBlock(hir::CompilerGenerated), |
| ThinVec::new()) |
| }; |
| |
| // push_unsafe!({ |
| // std::intrinsics::move_val_init(raw_place, pop_unsafe!( EXPR )); |
| // InPlace::finalize(place) |
| // }) |
| let expr = { |
| let ptr = self.expr_ident(e.span, p_ptr_ident, p_ptr_binding); |
| let call_move_val_init = |
| hir::StmtSemi( |
| make_call(self, &move_val_init, hir_vec![ptr, pop_unsafe_expr]), |
| self.next_id().node_id); |
| let call_move_val_init = respan(e.span, call_move_val_init); |
| |
| let place = self.expr_ident(e.span, place_ident, place_binding); |
| let call = make_call(self, &inplace_finalize, hir_vec![place]); |
| P(self.signal_block_expr(hir_vec![call_move_val_init], |
| call, |
| e.span, |
| hir::PushUnsafeBlock(hir::CompilerGenerated), |
| ThinVec::new())) |
| }; |
| |
| let block = self.block_all(e.span, hir_vec![s1, s2, s3], Some(expr)); |
| hir::ExprBlock(P(block)) |
| } |
| |
| ExprKind::Array(ref exprs) => { |
| hir::ExprArray(exprs.iter().map(|x| self.lower_expr(x)).collect()) |
| } |
| ExprKind::Repeat(ref expr, ref count) => { |
| let expr = P(self.lower_expr(expr)); |
| let count = self.lower_body(None, |this| this.lower_expr(count)); |
| hir::ExprRepeat(expr, count) |
| } |
| ExprKind::Tup(ref elts) => { |
| hir::ExprTup(elts.iter().map(|x| self.lower_expr(x)).collect()) |
| } |
| ExprKind::Call(ref f, ref args) => { |
| let f = P(self.lower_expr(f)); |
| hir::ExprCall(f, args.iter().map(|x| self.lower_expr(x)).collect()) |
| } |
| ExprKind::MethodCall(ref seg, ref args) => { |
| let hir_seg = self.lower_path_segment(e.span, seg, ParamMode::Optional, 0, |
| ParenthesizedGenericArgs::Err, |
| ImplTraitContext::Disallowed); |
| let args = args.iter().map(|x| self.lower_expr(x)).collect(); |
| hir::ExprMethodCall(hir_seg, seg.span, args) |
| } |
| ExprKind::Binary(binop, ref lhs, ref rhs) => { |
| let binop = self.lower_binop(binop); |
| let lhs = P(self.lower_expr(lhs)); |
| let rhs = P(self.lower_expr(rhs)); |
| hir::ExprBinary(binop, lhs, rhs) |
| } |
| ExprKind::Unary(op, ref ohs) => { |
| let op = self.lower_unop(op); |
| let ohs = P(self.lower_expr(ohs)); |
| hir::ExprUnary(op, ohs) |
| } |
| ExprKind::Lit(ref l) => hir::ExprLit(P((**l).clone())), |
| ExprKind::Cast(ref expr, ref ty) => { |
| let expr = P(self.lower_expr(expr)); |
| hir::ExprCast(expr, self.lower_ty(ty, ImplTraitContext::Disallowed)) |
| } |
| ExprKind::Type(ref expr, ref ty) => { |
| let expr = P(self.lower_expr(expr)); |
| hir::ExprType(expr, self.lower_ty(ty, ImplTraitContext::Disallowed)) |
| } |
| ExprKind::AddrOf(m, ref ohs) => { |
| let m = self.lower_mutability(m); |
| let ohs = P(self.lower_expr(ohs)); |
| hir::ExprAddrOf(m, ohs) |
| } |
| // More complicated than you might expect because the else branch |
| // might be `if let`. |
| ExprKind::If(ref cond, ref blk, ref else_opt) => { |
| let else_opt = else_opt.as_ref().map(|els| { |
| match els.node { |
| ExprKind::IfLet(..) => { |
| // wrap the if-let expr in a block |
| let span = els.span; |
| let els = P(self.lower_expr(els)); |
| let LoweredNodeId { |
| node_id, |
| hir_id, |
| } = self.next_id(); |
| let blk = P(hir::Block { |
| stmts: hir_vec![], |
| expr: Some(els), |
| id: node_id, |
| hir_id, |
| rules: hir::DefaultBlock, |
| span, |
| targeted_by_break: false, |
| recovered: blk.recovered, |
| }); |
| P(self.expr_block(blk, ThinVec::new())) |
| } |
| _ => P(self.lower_expr(els)), |
| } |
| }); |
| |
| let then_blk = self.lower_block(blk, false); |
| let then_expr = self.expr_block(then_blk, ThinVec::new()); |
| |
| hir::ExprIf(P(self.lower_expr(cond)), P(then_expr), else_opt) |
| } |
| ExprKind::While(ref cond, ref body, opt_ident) => { |
| self.with_loop_scope(e.id, |this| |
| hir::ExprWhile( |
| this.with_loop_condition_scope(|this| P(this.lower_expr(cond))), |
| this.lower_block(body, false), |
| this.lower_opt_sp_ident(opt_ident))) |
| } |
| ExprKind::Loop(ref body, opt_ident) => { |
| self.with_loop_scope(e.id, |this| |
| hir::ExprLoop(this.lower_block(body, false), |
| this.lower_opt_sp_ident(opt_ident), |
| hir::LoopSource::Loop)) |
| } |
| ExprKind::Catch(ref body) => { |
| self.with_catch_scope(body.id, |this| |
| hir::ExprBlock(this.lower_block(body, true))) |
| } |
| ExprKind::Match(ref expr, ref arms) => { |
| hir::ExprMatch(P(self.lower_expr(expr)), |
| arms.iter().map(|x| self.lower_arm(x)).collect(), |
| hir::MatchSource::Normal) |
| } |
| ExprKind::Closure(capture_clause, ref decl, ref body, fn_decl_span) => { |
| self.with_new_scopes(|this| { |
| this.with_parent_def(e.id, |this| { |
| let mut is_generator = false; |
| let body_id = this.lower_body(Some(decl), |this| { |
| let e = this.lower_expr(body); |
| is_generator = this.is_generator; |
| e |
| }); |
| if is_generator && !decl.inputs.is_empty() { |
| span_err!(this.sess, fn_decl_span, E0628, |
| "generators cannot have explicit arguments"); |
| this.sess.abort_if_errors(); |
| } |
| hir::ExprClosure(this.lower_capture_clause(capture_clause), |
| this.lower_fn_decl(decl, None, false), |
| body_id, |
| fn_decl_span, |
| is_generator) |
| }) |
| }) |
| } |
| ExprKind::Block(ref blk) => hir::ExprBlock(self.lower_block(blk, false)), |
| ExprKind::Assign(ref el, ref er) => { |
| hir::ExprAssign(P(self.lower_expr(el)), P(self.lower_expr(er))) |
| } |
| ExprKind::AssignOp(op, ref el, ref er) => { |
| hir::ExprAssignOp(self.lower_binop(op), |
| P(self.lower_expr(el)), |
| P(self.lower_expr(er))) |
| } |
| ExprKind::Field(ref el, ident) => { |
| hir::ExprField(P(self.lower_expr(el)), |
| respan(ident.span, self.lower_ident(ident.node))) |
| } |
| ExprKind::TupField(ref el, ident) => { |
| hir::ExprTupField(P(self.lower_expr(el)), ident) |
| } |
| ExprKind::Index(ref el, ref er) => { |
| hir::ExprIndex(P(self.lower_expr(el)), P(self.lower_expr(er))) |
| } |
| ExprKind::Range(ref e1, ref e2, lims) => { |
| use syntax::ast::RangeLimits::*; |
| |
| let path = match (e1, e2, lims) { |
| (&None, &None, HalfOpen) => "RangeFull", |
| (&Some(..), &None, HalfOpen) => "RangeFrom", |
| (&None, &Some(..), HalfOpen) => "RangeTo", |
| (&Some(..), &Some(..), HalfOpen) => "Range", |
| (&None, &Some(..), Closed) => "RangeToInclusive", |
| (&Some(..), &Some(..), Closed) => "RangeInclusive", |
| (_, &None, Closed) => |
| panic!(self.diagnostic().span_fatal( |
| e.span, "inclusive range with no end")), |
| }; |
| |
| let fields = |
| e1.iter().map(|e| ("start", e)).chain(e2.iter().map(|e| ("end", e))) |
| .map(|(s, e)| { |
| let expr = P(self.lower_expr(&e)); |
| let unstable_span = |
| self.allow_internal_unstable(CompilerDesugaringKind::DotFill, e.span); |
| self.field(Symbol::intern(s), expr, unstable_span) |
| }).collect::<P<[hir::Field]>>(); |
| |
| let is_unit = fields.is_empty(); |
| let unstable_span = |
| self.allow_internal_unstable(CompilerDesugaringKind::DotFill, e.span); |
| let struct_path = |
| iter::once("ops").chain(iter::once(path)) |
| .collect::<Vec<_>>(); |
| let struct_path = self.std_path(unstable_span, &struct_path, is_unit); |
| let struct_path = hir::QPath::Resolved(None, P(struct_path)); |
| |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(e.id); |
| |
| return hir::Expr { |
| id: node_id, |
| hir_id, |
| node: if is_unit { |
| hir::ExprPath(struct_path) |
| } else { |
| hir::ExprStruct(struct_path, fields, None) |
| }, |
| span: unstable_span, |
| attrs: e.attrs.clone(), |
| }; |
| } |
| ExprKind::Path(ref qself, ref path) => { |
| hir::ExprPath(self.lower_qpath(e.id, qself, path, ParamMode::Optional, |
| ImplTraitContext::Disallowed)) |
| } |
| ExprKind::Break(opt_ident, ref opt_expr) => { |
| let label_result = if self.is_in_loop_condition && opt_ident.is_none() { |
| hir::Destination { |
| ident: opt_ident, |
| target_id: hir::ScopeTarget::Loop( |
| Err(hir::LoopIdError::UnlabeledCfInWhileCondition).into()), |
| } |
| } else { |
| self.lower_loop_destination(opt_ident.map(|ident| (e.id, ident))) |
| }; |
| hir::ExprBreak( |
| label_result, |
| opt_expr.as_ref().map(|x| P(self.lower_expr(x)))) |
| } |
| ExprKind::Continue(opt_ident) => |
| hir::ExprAgain( |
| if self.is_in_loop_condition && opt_ident.is_none() { |
| hir::Destination { |
| ident: opt_ident, |
| target_id: hir::ScopeTarget::Loop(Err( |
| hir::LoopIdError::UnlabeledCfInWhileCondition).into()), |
| } |
| } else { |
| self.lower_loop_destination(opt_ident.map( |ident| (e.id, ident))) |
| }), |
| ExprKind::Ret(ref e) => hir::ExprRet(e.as_ref().map(|x| P(self.lower_expr(x)))), |
| ExprKind::InlineAsm(ref asm) => { |
| let hir_asm = hir::InlineAsm { |
| inputs: asm.inputs.iter().map(|&(ref c, _)| c.clone()).collect(), |
| outputs: asm.outputs.iter().map(|out| { |
| hir::InlineAsmOutput { |
| constraint: out.constraint.clone(), |
| is_rw: out.is_rw, |
| is_indirect: out.is_indirect, |
| } |
| }).collect(), |
| asm: asm.asm.clone(), |
| asm_str_style: asm.asm_str_style, |
| clobbers: asm.clobbers.clone().into(), |
| volatile: asm.volatile, |
| alignstack: asm.alignstack, |
| dialect: asm.dialect, |
| ctxt: asm.ctxt, |
| }; |
| let outputs = |
| asm.outputs.iter().map(|out| self.lower_expr(&out.expr)).collect(); |
| let inputs = |
| asm.inputs.iter().map(|&(_, ref input)| self.lower_expr(input)).collect(); |
| hir::ExprInlineAsm(P(hir_asm), outputs, inputs) |
| } |
| ExprKind::Struct(ref path, ref fields, ref maybe_expr) => { |
| hir::ExprStruct(self.lower_qpath(e.id, &None, path, ParamMode::Optional, |
| ImplTraitContext::Disallowed), |
| fields.iter().map(|x| self.lower_field(x)).collect(), |
| maybe_expr.as_ref().map(|x| P(self.lower_expr(x)))) |
| } |
| ExprKind::Paren(ref ex) => { |
| let mut ex = self.lower_expr(ex); |
| // include parens in span, but only if it is a super-span. |
| if e.span.contains(ex.span) { |
| ex.span = e.span; |
| } |
| // merge attributes into the inner expression. |
| let mut attrs = e.attrs.clone(); |
| attrs.extend::<Vec<_>>(ex.attrs.into()); |
| ex.attrs = attrs; |
| return ex; |
| } |
| |
| ExprKind::Yield(ref opt_expr) => { |
| self.is_generator = true; |
| let expr = opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| { |
| self.expr(e.span, hir::ExprTup(hir_vec![]), ThinVec::new()) |
| }); |
| hir::ExprYield(P(expr)) |
| } |
| |
| // Desugar ExprIfLet |
| // From: `if let <pat> = <sub_expr> <body> [<else_opt>]` |
| ExprKind::IfLet(ref pat, ref sub_expr, ref body, ref else_opt) => { |
| // to: |
| // |
| // match <sub_expr> { |
| // <pat> => <body>, |
| // _ => [<else_opt> | ()] |
| // } |
| |
| let mut arms = vec![]; |
| |
| // `<pat> => <body>` |
| { |
| let body = self.lower_block(body, false); |
| let body_expr = P(self.expr_block(body, ThinVec::new())); |
| let pat = self.lower_pat(pat); |
| arms.push(self.arm(hir_vec![pat], body_expr)); |
| } |
| |
| // _ => [<else_opt>|()] |
| { |
| let wildcard_arm: Option<&Expr> = else_opt.as_ref().map(|p| &**p); |
| let wildcard_pattern = self.pat_wild(e.span); |
| let body = if let Some(else_expr) = wildcard_arm { |
| P(self.lower_expr(else_expr)) |
| } else { |
| self.expr_tuple(e.span, hir_vec![]) |
| }; |
| arms.push(self.arm(hir_vec![wildcard_pattern], body)); |
| } |
| |
| let contains_else_clause = else_opt.is_some(); |
| |
| let sub_expr = P(self.lower_expr(sub_expr)); |
| |
| hir::ExprMatch( |
| sub_expr, |
| arms.into(), |
| hir::MatchSource::IfLetDesugar { |
| contains_else_clause, |
| }) |
| } |
| |
| // Desugar ExprWhileLet |
| // From: `[opt_ident]: while let <pat> = <sub_expr> <body>` |
| ExprKind::WhileLet(ref pat, ref sub_expr, ref body, opt_ident) => { |
| // to: |
| // |
| // [opt_ident]: loop { |
| // match <sub_expr> { |
| // <pat> => <body>, |
| // _ => break |
| // } |
| // } |
| |
| // Note that the block AND the condition are evaluated in the loop scope. |
| // This is done to allow `break` from inside the condition of the loop. |
| let (body, break_expr, sub_expr) = self.with_loop_scope(e.id, |this| ( |
| this.lower_block(body, false), |
| this.expr_break(e.span, ThinVec::new()), |
| this.with_loop_condition_scope(|this| P(this.lower_expr(sub_expr))), |
| )); |
| |
| // `<pat> => <body>` |
| let pat_arm = { |
| let body_expr = P(self.expr_block(body, ThinVec::new())); |
| let pat = self.lower_pat(pat); |
| self.arm(hir_vec![pat], body_expr) |
| }; |
| |
| // `_ => break` |
| let break_arm = { |
| let pat_under = self.pat_wild(e.span); |
| self.arm(hir_vec![pat_under], break_expr) |
| }; |
| |
| // `match <sub_expr> { ... }` |
| let arms = hir_vec![pat_arm, break_arm]; |
| let match_expr = self.expr(e.span, |
| hir::ExprMatch(sub_expr, |
| arms, |
| hir::MatchSource::WhileLetDesugar), |
| ThinVec::new()); |
| |
| // `[opt_ident]: loop { ... }` |
| let loop_block = P(self.block_expr(P(match_expr))); |
| let loop_expr = hir::ExprLoop(loop_block, self.lower_opt_sp_ident(opt_ident), |
| hir::LoopSource::WhileLet); |
| // add attributes to the outer returned expr node |
| loop_expr |
| } |
| |
| // Desugar ExprForLoop |
| // From: `[opt_ident]: for <pat> in <head> <body>` |
| ExprKind::ForLoop(ref pat, ref head, ref body, opt_ident) => { |
| // to: |
| // |
| // { |
| // let result = match ::std::iter::IntoIterator::into_iter(<head>) { |
| // mut iter => { |
| // [opt_ident]: loop { |
| // let mut __next; |
| // match ::std::iter::Iterator::next(&mut iter) { |
| // ::std::option::Option::Some(val) => __next = val, |
| // ::std::option::Option::None => break |
| // }; |
| // let <pat> = __next; |
| // StmtExpr(<body>); |
| // } |
| // } |
| // }; |
| // result |
| // } |
| |
| // expand <head> |
| let head = self.lower_expr(head); |
| |
| let iter = self.str_to_ident("iter"); |
| |
| let next_ident = self.str_to_ident("__next"); |
| let next_pat = self.pat_ident_binding_mode(e.span, |
| next_ident, |
| hir::BindingAnnotation::Mutable); |
| |
| // `::std::option::Option::Some(val) => next = val` |
| let pat_arm = { |
| let val_ident = self.str_to_ident("val"); |
| let val_pat = self.pat_ident(e.span, val_ident); |
| let val_expr = P(self.expr_ident(e.span, val_ident, val_pat.id)); |
| let next_expr = P(self.expr_ident(e.span, next_ident, next_pat.id)); |
| let assign = P(self.expr(e.span, |
| hir::ExprAssign(next_expr, val_expr), |
| ThinVec::new())); |
| let some_pat = self.pat_some(e.span, val_pat); |
| self.arm(hir_vec![some_pat], assign) |
| }; |
| |
| // `::std::option::Option::None => break` |
| let break_arm = { |
| let break_expr = self.with_loop_scope(e.id, |this| |
| this.expr_break(e.span, ThinVec::new())); |
| let pat = self.pat_none(e.span); |
| self.arm(hir_vec![pat], break_expr) |
| }; |
| |
| // `mut iter` |
| let iter_pat = self.pat_ident_binding_mode(e.span, |
| iter, |
| hir::BindingAnnotation::Mutable); |
| |
| // `match ::std::iter::Iterator::next(&mut iter) { ... }` |
| let match_expr = { |
| let iter = P(self.expr_ident(e.span, iter, iter_pat.id)); |
| let ref_mut_iter = self.expr_mut_addr_of(e.span, iter); |
| let next_path = &["iter", "Iterator", "next"]; |
| let next_path = P(self.expr_std_path(e.span, next_path, ThinVec::new())); |
| let next_expr = P(self.expr_call(e.span, next_path, |
| hir_vec![ref_mut_iter])); |
| let arms = hir_vec![pat_arm, break_arm]; |
| |
| P(self.expr(e.span, |
| hir::ExprMatch(next_expr, arms, |
| hir::MatchSource::ForLoopDesugar), |
| ThinVec::new())) |
| }; |
| let match_stmt = respan(e.span, hir::StmtExpr(match_expr, self.next_id().node_id)); |
| |
| let next_expr = P(self.expr_ident(e.span, next_ident, next_pat.id)); |
| |
| // `let mut __next` |
| let next_let = self.stmt_let_pat(e.span, |
| None, |
| next_pat, |
| hir::LocalSource::ForLoopDesugar); |
| |
| // `let <pat> = __next` |
| let pat = self.lower_pat(pat); |
| let pat_let = self.stmt_let_pat(e.span, |
| Some(next_expr), |
| pat, |
| hir::LocalSource::ForLoopDesugar); |
| |
| let body_block = self.with_loop_scope(e.id, |
| |this| this.lower_block(body, false)); |
| let body_expr = P(self.expr_block(body_block, ThinVec::new())); |
| let body_stmt = respan(e.span, hir::StmtExpr(body_expr, self.next_id().node_id)); |
| |
| let loop_block = P(self.block_all(e.span, |
| hir_vec![next_let, |
| match_stmt, |
| pat_let, |
| body_stmt], |
| None)); |
| |
| // `[opt_ident]: loop { ... }` |
| let loop_expr = hir::ExprLoop(loop_block, self.lower_opt_sp_ident(opt_ident), |
| hir::LoopSource::ForLoop); |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(e.id); |
| let loop_expr = P(hir::Expr { |
| id: node_id, |
| hir_id, |
| node: loop_expr, |
| span: e.span, |
| attrs: ThinVec::new(), |
| }); |
| |
| // `mut iter => { ... }` |
| let iter_arm = self.arm(hir_vec![iter_pat], loop_expr); |
| |
| // `match ::std::iter::IntoIterator::into_iter(<head>) { ... }` |
| let into_iter_expr = { |
| let into_iter_path = &["iter", "IntoIterator", "into_iter"]; |
| let into_iter = P(self.expr_std_path(e.span, into_iter_path, |
| ThinVec::new())); |
| P(self.expr_call(e.span, into_iter, hir_vec![head])) |
| }; |
| |
| let match_expr = P(self.expr_match(e.span, |
| into_iter_expr, |
| hir_vec![iter_arm], |
| hir::MatchSource::ForLoopDesugar)); |
| |
| // `{ let _result = ...; _result }` |
| // underscore prevents an unused_variables lint if the head diverges |
| let result_ident = self.str_to_ident("_result"); |
| let (let_stmt, let_stmt_binding) = |
| self.stmt_let(e.span, false, result_ident, match_expr); |
| |
| let result = P(self.expr_ident(e.span, result_ident, let_stmt_binding)); |
| let block = P(self.block_all(e.span, hir_vec![let_stmt], Some(result))); |
| // add the attributes to the outer returned expr node |
| return self.expr_block(block, e.attrs.clone()); |
| } |
| |
| // Desugar ExprKind::Try |
| // From: `<expr>?` |
| ExprKind::Try(ref sub_expr) => { |
| // to: |
| // |
| // match Try::into_result(<expr>) { |
| // Ok(val) => #[allow(unreachable_code)] val, |
| // Err(err) => #[allow(unreachable_code)] |
| // // If there is an enclosing `catch {...}` |
| // break 'catch_target Try::from_error(From::from(err)), |
| // // Otherwise |
| // return Try::from_error(From::from(err)), |
| // } |
| |
| let unstable_span = |
| self.allow_internal_unstable(CompilerDesugaringKind::QuestionMark, e.span); |
| |
| // Try::into_result(<expr>) |
| let discr = { |
| // expand <expr> |
| let sub_expr = self.lower_expr(sub_expr); |
| |
| let path = &["ops", "Try", "into_result"]; |
| let path = P(self.expr_std_path(unstable_span, path, ThinVec::new())); |
| P(self.expr_call(e.span, path, hir_vec![sub_expr])) |
| }; |
| |
| // #[allow(unreachable_code)] |
| let attr = { |
| // allow(unreachable_code) |
| let allow = { |
| let allow_ident = self.str_to_ident("allow"); |
| let uc_ident = self.str_to_ident("unreachable_code"); |
| let uc_meta_item = attr::mk_spanned_word_item(e.span, uc_ident); |
| let uc_nested = NestedMetaItemKind::MetaItem(uc_meta_item); |
| let uc_spanned = respan(e.span, uc_nested); |
| attr::mk_spanned_list_item(e.span, allow_ident, vec![uc_spanned]) |
| }; |
| attr::mk_spanned_attr_outer(e.span, attr::mk_attr_id(), allow) |
| }; |
| let attrs = vec![attr]; |
| |
| // Ok(val) => #[allow(unreachable_code)] val, |
| let ok_arm = { |
| let val_ident = self.str_to_ident("val"); |
| let val_pat = self.pat_ident(e.span, val_ident); |
| let val_expr = P(self.expr_ident_with_attrs(e.span, |
| val_ident, |
| val_pat.id, |
| ThinVec::from(attrs.clone()))); |
| let ok_pat = self.pat_ok(e.span, val_pat); |
| |
| self.arm(hir_vec![ok_pat], val_expr) |
| }; |
| |
| // Err(err) => #[allow(unreachable_code)] |
| // return Try::from_error(From::from(err)), |
| let err_arm = { |
| let err_ident = self.str_to_ident("err"); |
| let err_local = self.pat_ident(e.span, err_ident); |
| let from_expr = { |
| let path = &["convert", "From", "from"]; |
| let from = P(self.expr_std_path(e.span, path, ThinVec::new())); |
| let err_expr = self.expr_ident(e.span, err_ident, err_local.id); |
| |
| self.expr_call(e.span, from, hir_vec![err_expr]) |
| }; |
| let from_err_expr = { |
| let path = &["ops", "Try", "from_error"]; |
| let from_err = P(self.expr_std_path(unstable_span, path, |
| ThinVec::new())); |
| P(self.expr_call(e.span, from_err, hir_vec![from_expr])) |
| }; |
| |
| let thin_attrs = ThinVec::from(attrs); |
| let catch_scope = self.catch_scopes.last().map(|x| *x); |
| let ret_expr = if let Some(catch_node) = catch_scope { |
| P(self.expr( |
| e.span, |
| hir::ExprBreak( |
| hir::Destination { |
| ident: None, |
| target_id: hir::ScopeTarget::Block(catch_node), |
| }, |
| Some(from_err_expr) |
| ), |
| thin_attrs)) |
| } else { |
| P(self.expr(e.span, |
| hir::Expr_::ExprRet(Some(from_err_expr)), |
| thin_attrs)) |
| }; |
| |
| |
| let err_pat = self.pat_err(e.span, err_local); |
| self.arm(hir_vec![err_pat], ret_expr) |
| }; |
| |
| hir::ExprMatch(discr, |
| hir_vec![err_arm, ok_arm], |
| hir::MatchSource::TryDesugar) |
| } |
| |
| ExprKind::Mac(_) => panic!("Shouldn't exist here"), |
| }; |
| |
| let LoweredNodeId { node_id, hir_id } = self.lower_node_id(e.id); |
| |
| hir::Expr { |
| id: node_id, |
| hir_id, |
| node: kind, |
| span: e.span, |
| attrs: e.attrs.clone(), |
| } |
| } |
| |
| fn lower_stmt(&mut self, s: &Stmt) -> SmallVector<hir::Stmt> { |
| SmallVector::one(match s.node { |
| StmtKind::Local(ref l) => Spanned { |
| node: hir::StmtDecl(P(Spanned { |
| node: hir::DeclLocal(self.lower_local(l)), |
| span: s.span, |
| }), self.lower_node_id(s.id).node_id), |
| span: s.span, |
| }, |
| StmtKind::Item(ref it) => { |
| // Can only use the ID once. |
| let mut id = Some(s.id); |
| return self.lower_item_id(it).into_iter().map(|item_id| Spanned { |
| node: hir::StmtDecl(P(Spanned { |
| node: hir::DeclItem(item_id), |
| span: s.span, |
| }), id.take() |
| .map(|id| self.lower_node_id(id).node_id) |
| .unwrap_or_else(|| self.next_id().node_id)), |
| span: s.span, |
| }).collect(); |
| } |
| StmtKind::Expr(ref e) => { |
| Spanned { |
| node: hir::StmtExpr(P(self.lower_expr(e)), |
| self.lower_node_id(s.id).node_id), |
| span: s.span, |
| } |
| } |
| StmtKind::Semi(ref e) => { |
| Spanned { |
| node: hir::StmtSemi(P(self.lower_expr(e)), |
| self.lower_node_id(s.id).node_id), |
| span: s.span, |
| } |
| } |
| StmtKind::Mac(..) => panic!("Shouldn't exist here"), |
| }) |
| } |
| |
| fn lower_capture_clause(&mut self, c: CaptureBy) -> hir::CaptureClause { |
| match c { |
| CaptureBy::Value => hir::CaptureByValue, |
| CaptureBy::Ref => hir::CaptureByRef, |
| } |
| } |
| |
| /// If an `explicit_owner` is given, this method allocates the `HirId` in |
| /// the address space of that item instead of the item currently being |
| /// lowered. This can happen during `lower_impl_item_ref()` where we need to |
| /// lower a `Visibility` value although we haven't lowered the owning |
| /// `ImplItem` in question yet. |
| fn lower_visibility(&mut self, |
| v: &Visibility, |
| explicit_owner: Option<NodeId>) |
| -> hir::Visibility { |
| match *v { |
| Visibility::Public => hir::Public, |
| Visibility::Crate(..) => hir::Visibility::Crate, |
| Visibility::Restricted { ref path, id } => { |
| hir::Visibility::Restricted { |
| path: P(self.lower_path(id, path, ParamMode::Explicit, true)), |
| id: if let Some(owner) = explicit_owner { |
| self.lower_node_id_with_owner(id, owner).node_id |
| } else { |
| self.lower_node_id(id).node_id |
| } |
| } |
| } |
| Visibility::Inherited => hir::Inherited, |
| } |
| } |
| |
| fn lower_defaultness(&mut self, d: Defaultness, has_value: bool) -> hir::Defaultness { |
| match d { |
| Defaultness::Default => hir::Defaultness::Default { has_value: has_value }, |
| Defaultness::Final => { |
| assert!(has_value); |
| hir::Defaultness::Final |
| } |
| } |
| } |
| |
| fn lower_block_check_mode(&mut self, b: &BlockCheckMode) -> hir::BlockCheckMode { |
| match *b { |
| BlockCheckMode::Default => hir::DefaultBlock, |
| BlockCheckMode::Unsafe(u) => hir::UnsafeBlock(self.lower_unsafe_source(u)), |
| } |
| } |
| |
| fn lower_binding_mode(&mut self, b: &BindingMode) -> hir::BindingAnnotation { |
| match *b { |
| BindingMode::ByValue(Mutability::Immutable) => |
| hir::BindingAnnotation::Unannotated, |
| BindingMode::ByRef(Mutability::Immutable) => hir::BindingAnnotation::Ref, |
| BindingMode::ByValue(Mutability::Mutable) => hir::BindingAnnotation::Mutable, |
| BindingMode::ByRef(Mutability::Mutable) => hir::BindingAnnotation::RefMut, |
| } |
| } |
| |
| fn lower_unsafe_source(&mut self, u: UnsafeSource) -> hir::UnsafeSource { |
| match u { |
| CompilerGenerated => hir::CompilerGenerated, |
| UserProvided => hir::UserProvided, |
| } |
| } |
| |
| fn lower_impl_polarity(&mut self, i: ImplPolarity) -> hir::ImplPolarity { |
| match i { |
| ImplPolarity::Positive => hir::ImplPolarity::Positive, |
| ImplPolarity::Negative => hir::ImplPolarity::Negative, |
| } |
| } |
| |
| fn lower_trait_bound_modifier(&mut self, f: TraitBoundModifier) -> hir::TraitBoundModifier { |
| match f { |
| TraitBoundModifier::None => hir::TraitBoundModifier::None, |
| TraitBoundModifier::Maybe => hir::TraitBoundModifier::Maybe, |
| } |
| } |
| |
| // Helper methods for building HIR. |
| |
| fn arm(&mut self, pats: hir::HirVec<P<hir::Pat>>, expr: P<hir::Expr>) -> hir::Arm { |
| hir::Arm { |
| attrs: hir_vec![], |
| pats, |
| guard: None, |
| body: expr, |
| } |
| } |
| |
| fn field(&mut self, name: Name, expr: P<hir::Expr>, span: Span) -> hir::Field { |
| hir::Field { |
| name: Spanned { |
| node: name, |
| span, |
| }, |
| span, |
| expr, |
| is_shorthand: false, |
| } |
| } |
| |
| fn expr_break(&mut self, span: Span, attrs: ThinVec<Attribute>) -> P<hir::Expr> { |
| let expr_break = hir::ExprBreak(self.lower_loop_destination(None), None); |
| P(self.expr(span, expr_break, attrs)) |
| } |
| |
| fn expr_call(&mut self, span: Span, e: P<hir::Expr>, args: hir::HirVec<hir::Expr>) |
| -> hir::Expr { |
| self.expr(span, hir::ExprCall(e, args), ThinVec::new()) |
| } |
| |
| fn expr_ident(&mut self, span: Span, id: Name, binding: NodeId) -> hir::Expr { |
| self.expr_ident_with_attrs(span, id, binding, ThinVec::new()) |
| } |
| |
| fn expr_ident_with_attrs(&mut self, span: Span, |
| id: Name, |
| binding: NodeId, |
| attrs: ThinVec<Attribute>) -> hir::Expr { |
| let expr_path = hir::ExprPath(hir::QPath::Resolved(None, P(hir::Path { |
| span, |
| def: Def::Local(binding), |
| segments: hir_vec![hir::PathSegment::from_name(id)], |
| }))); |
| |
| self.expr(span, expr_path, attrs) |
| } |
| |
| fn expr_mut_addr_of(&mut self, span: Span, e: P<hir::Expr>) -> hir::Expr { |
| self.expr(span, hir::ExprAddrOf(hir::MutMutable, e), ThinVec::new()) |
| } |
| |
| fn expr_std_path(&mut self, |
| span: Span, |
| components: &[&str], |
| attrs: ThinVec<Attribute>) |
| -> hir::Expr { |
| let path = self.std_path(span, components, true); |
| self.expr(span, hir::ExprPath(hir::QPath::Resolved(None, P(path))), attrs) |
| } |
| |
| fn expr_match(&mut self, |
| span: Span, |
| arg: P<hir::Expr>, |
| arms: hir::HirVec<hir::Arm>, |
| source: hir::MatchSource) |
| -> hir::Expr { |
| self.expr(span, hir::ExprMatch(arg, arms, source), ThinVec::new()) |
| } |
| |
| fn expr_block(&mut self, b: P<hir::Block>, attrs: ThinVec<Attribute>) -> hir::Expr { |
| self.expr(b.span, hir::ExprBlock(b), attrs) |
| } |
| |
| fn expr_tuple(&mut self, sp: Span, exprs: hir::HirVec<hir::Expr>) -> P<hir::Expr> { |
| P(self.expr(sp, hir::ExprTup(exprs), ThinVec::new())) |
| } |
| |
| fn expr(&mut self, span: Span, node: hir::Expr_, attrs: ThinVec<Attribute>) -> hir::Expr { |
| let LoweredNodeId { node_id, hir_id } = self.next_id(); |
| hir::Expr { |
| id: node_id, |
| hir_id, |
| node, |
| span, |
| attrs, |
| } |
| } |
| |
| fn stmt_let_pat(&mut self, |
| sp: Span, |
| ex: Option<P<hir::Expr>>, |
| pat: P<hir::Pat>, |
| source: hir::LocalSource) |
| -> hir::Stmt { |
| let LoweredNodeId { node_id, hir_id } = self.next_id(); |
| |
| let local = P(hir::Local { |
| pat, |
| ty: None, |
| init: ex, |
| id: node_id, |
| hir_id, |
| span: sp, |
| attrs: ThinVec::new(), |
| source, |
| }); |
| let decl = respan(sp, hir::DeclLocal(local)); |
| respan(sp, hir::StmtDecl(P(decl), self.next_id().node_id)) |
| } |
| |
| fn stmt_let(&mut self, sp: Span, mutbl: bool, ident: Name, ex: P<hir::Expr>) |
| -> (hir::Stmt, NodeId) { |
| let pat = if mutbl { |
| self.pat_ident_binding_mode(sp, ident, hir::BindingAnnotation::Mutable) |
| } else { |
| self.pat_ident(sp, ident) |
| }; |
| let pat_id = pat.id; |
| (self.stmt_let_pat(sp, Some(ex), pat, hir::LocalSource::Normal), pat_id) |
| } |
| |
| fn block_expr(&mut self, expr: P<hir::Expr>) -> hir::Block { |
| self.block_all(expr.span, hir::HirVec::new(), Some(expr)) |
| } |
| |
| fn block_all(&mut self, span: Span, stmts: hir::HirVec<hir::Stmt>, expr: Option<P<hir::Expr>>) |
| -> hir::Block { |
| let LoweredNodeId { node_id, hir_id } = self.next_id(); |
| |
| hir::Block { |
| stmts, |
| expr, |
| id: node_id, |
| hir_id, |
| rules: hir::DefaultBlock, |
| span, |
| targeted_by_break: false, |
| recovered: false, |
| } |
| } |
| |
| fn pat_ok(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> { |
| self.pat_std_enum(span, &["result", "Result", "Ok"], hir_vec![pat]) |
| } |
| |
| fn pat_err(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> { |
| self.pat_std_enum(span, &["result", "Result", "Err"], hir_vec![pat]) |
| } |
| |
| fn pat_some(&mut self, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> { |
| self.pat_std_enum(span, &["option", "Option", "Some"], hir_vec![pat]) |
| } |
| |
| fn pat_none(&mut self, span: Span) -> P<hir::Pat> { |
| self.pat_std_enum(span, &["option", "Option", "None"], hir_vec![]) |
| } |
| |
| fn pat_std_enum(&mut self, |
| span: Span, |
| components: &[&str], |
| subpats: hir::HirVec<P<hir::Pat>>) |
| -> P<hir::Pat> { |
| let path = self.std_path(span, components, true); |
| let qpath = hir::QPath::Resolved(None, P(path)); |
| let pt = if subpats.is_empty() { |
| hir::PatKind::Path(qpath) |
| } else { |
| hir::PatKind::TupleStruct(qpath, subpats, None) |
| }; |
| self.pat(span, pt) |
| } |
| |
| fn pat_ident(&mut self, span: Span, name: Name) -> P<hir::Pat> { |
| self.pat_ident_binding_mode(span, name, hir::BindingAnnotation::Unannotated) |
| } |
| |
| fn pat_ident_binding_mode(&mut self, span: Span, name: Name, bm: hir::BindingAnnotation) |
| -> P<hir::Pat> { |
| let LoweredNodeId { node_id, hir_id } = self.next_id(); |
| |
| P(hir::Pat { |
| id: node_id, |
| hir_id, |
| node: hir::PatKind::Binding(bm, |
| node_id, |
| Spanned { |
| span, |
| node: name, |
| }, |
| None), |
| span, |
| }) |
| } |
| |
| fn pat_wild(&mut self, span: Span) -> P<hir::Pat> { |
| self.pat(span, hir::PatKind::Wild) |
| } |
| |
| fn pat(&mut self, span: Span, pat: hir::PatKind) -> P<hir::Pat> { |
| let LoweredNodeId { node_id, hir_id } = self.next_id(); |
| P(hir::Pat { |
| id: node_id, |
| hir_id, |
| node: pat, |
| span, |
| }) |
| } |
| |
| /// Given suffix ["b","c","d"], returns path `::std::b::c::d` when |
| /// `fld.cx.use_std`, and `::core::b::c::d` otherwise. |
| /// The path is also resolved according to `is_value`. |
| fn std_path(&mut self, span: Span, components: &[&str], is_value: bool) -> hir::Path { |
| let mut path = hir::Path { |
| span, |
| def: Def::Err, |
| segments: iter::once(keywords::CrateRoot.name()).chain({ |
| self.crate_root.into_iter().chain(components.iter().cloned()).map(Symbol::intern) |
| }).map(hir::PathSegment::from_name).collect(), |
| }; |
| |
| self.resolver.resolve_hir_path(&mut path, is_value); |
| path |
| } |
| |
| fn signal_block_expr(&mut self, |
| stmts: hir::HirVec<hir::Stmt>, |
| expr: P<hir::Expr>, |
| span: Span, |
| rule: hir::BlockCheckMode, |
| attrs: ThinVec<Attribute>) |
| -> hir::Expr { |
| let LoweredNodeId { node_id, hir_id } = self.next_id(); |
| |
| let block = P(hir::Block { |
| rules: rule, |
| span, |
| id: node_id, |
| hir_id, |
| stmts, |
| expr: Some(expr), |
| targeted_by_break: false, |
| recovered: false, |
| }); |
| self.expr_block(block, attrs) |
| } |
| |
| fn ty_path(&mut self, id: LoweredNodeId, span: Span, qpath: hir::QPath) -> P<hir::Ty> { |
| let mut id = id; |
| let node = match qpath { |
| hir::QPath::Resolved(None, path) => { |
| // Turn trait object paths into `TyTraitObject` instead. |
| if let Def::Trait(_) = path.def { |
| let principal = hir::PolyTraitRef { |
| bound_generic_params: hir::HirVec::new(), |
| trait_ref: hir::TraitRef { |
| path: path.and_then(|path| path), |
| ref_id: id.node_id, |
| }, |
| span, |
| }; |
| |
| // The original ID is taken by the `PolyTraitRef`, |
| // so the `Ty` itself needs a different one. |
| id = self.next_id(); |
| |
| hir::TyTraitObject(hir_vec![principal], self.elided_lifetime(span)) |
| } else { |
| hir::TyPath(hir::QPath::Resolved(None, path)) |
| } |
| } |
| _ => hir::TyPath(qpath) |
| }; |
| P(hir::Ty { id: id.node_id, hir_id: id.hir_id, node, span }) |
| } |
| |
| fn elided_lifetime(&mut self, span: Span) -> hir::Lifetime { |
| hir::Lifetime { |
| id: self.next_id().node_id, |
| span, |
| name: hir::LifetimeName::Implicit, |
| } |
| } |
| } |
| |
| fn body_ids(bodies: &BTreeMap<hir::BodyId, hir::Body>) -> Vec<hir::BodyId> { |
| // Sorting by span ensures that we get things in order within a |
| // file, and also puts the files in a sensible order. |
| let mut body_ids: Vec<_> = bodies.keys().cloned().collect(); |
| body_ids.sort_by_key(|b| bodies[b].value.span); |
| body_ids |
| } |