| // Copyright 2012-2015 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. |
| |
| use hir::def_id::DefId; |
| use ty::{self, BoundRegion, Region, Ty, TyCtxt}; |
| use std::fmt; |
| use rustc_target::spec::abi; |
| use syntax::ast; |
| use errors::DiagnosticBuilder; |
| use syntax_pos::Span; |
| |
| use hir; |
| |
| #[derive(Clone, Copy, Debug)] |
| pub struct ExpectedFound<T> { |
| pub expected: T, |
| pub found: T, |
| } |
| |
| // Data structures used in type unification |
| #[derive(Clone, Debug)] |
| pub enum TypeError<'tcx> { |
| Mismatch, |
| UnsafetyMismatch(ExpectedFound<hir::Unsafety>), |
| AbiMismatch(ExpectedFound<abi::Abi>), |
| Mutability, |
| TupleSize(ExpectedFound<usize>), |
| FixedArraySize(ExpectedFound<u64>), |
| ArgCount, |
| |
| RegionsDoesNotOutlive(Region<'tcx>, Region<'tcx>), |
| RegionsInsufficientlyPolymorphic(BoundRegion, Region<'tcx>), |
| RegionsOverlyPolymorphic(BoundRegion, Region<'tcx>), |
| |
| Sorts(ExpectedFound<Ty<'tcx>>), |
| IntMismatch(ExpectedFound<ty::IntVarValue>), |
| FloatMismatch(ExpectedFound<ast::FloatTy>), |
| Traits(ExpectedFound<DefId>), |
| VariadicMismatch(ExpectedFound<bool>), |
| |
| /// Instantiating a type variable with the given type would have |
| /// created a cycle (because it appears somewhere within that |
| /// type). |
| CyclicTy(Ty<'tcx>), |
| ProjectionMismatched(ExpectedFound<DefId>), |
| ProjectionBoundsLength(ExpectedFound<usize>), |
| ExistentialMismatch(ExpectedFound<&'tcx ty::Slice<ty::ExistentialPredicate<'tcx>>>), |
| |
| OldStyleLUB(Box<TypeError<'tcx>>), |
| } |
| |
| #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Hash, Debug, Copy)] |
| pub enum UnconstrainedNumeric { |
| UnconstrainedFloat, |
| UnconstrainedInt, |
| Neither, |
| } |
| |
| /// Explains the source of a type err in a short, human readable way. This is meant to be placed |
| /// in parentheses after some larger message. You should also invoke `note_and_explain_type_err()` |
| /// afterwards to present additional details, particularly when it comes to lifetime-related |
| /// errors. |
| impl<'tcx> fmt::Display for TypeError<'tcx> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| use self::TypeError::*; |
| fn report_maybe_different(f: &mut fmt::Formatter, |
| expected: String, found: String) -> fmt::Result { |
| // A naive approach to making sure that we're not reporting silly errors such as: |
| // (expected closure, found closure). |
| if expected == found { |
| write!(f, "expected {}, found a different {}", expected, found) |
| } else { |
| write!(f, "expected {}, found {}", expected, found) |
| } |
| } |
| |
| match *self { |
| CyclicTy(_) => write!(f, "cyclic type of infinite size"), |
| Mismatch => write!(f, "types differ"), |
| UnsafetyMismatch(values) => { |
| write!(f, "expected {} fn, found {} fn", |
| values.expected, |
| values.found) |
| } |
| AbiMismatch(values) => { |
| write!(f, "expected {} fn, found {} fn", |
| values.expected, |
| values.found) |
| } |
| Mutability => write!(f, "types differ in mutability"), |
| FixedArraySize(values) => { |
| write!(f, "expected an array with a fixed size of {} elements, \ |
| found one with {} elements", |
| values.expected, |
| values.found) |
| } |
| TupleSize(values) => { |
| write!(f, "expected a tuple with {} elements, \ |
| found one with {} elements", |
| values.expected, |
| values.found) |
| } |
| ArgCount => { |
| write!(f, "incorrect number of function parameters") |
| } |
| RegionsDoesNotOutlive(..) => { |
| write!(f, "lifetime mismatch") |
| } |
| RegionsInsufficientlyPolymorphic(br, _) => { |
| write!(f, |
| "expected bound lifetime parameter{}{}, found concrete lifetime", |
| if br.is_named() { " " } else { "" }, |
| br) |
| } |
| RegionsOverlyPolymorphic(br, _) => { |
| write!(f, |
| "expected concrete lifetime, found bound lifetime parameter{}{}", |
| if br.is_named() { " " } else { "" }, |
| br) |
| } |
| Sorts(values) => ty::tls::with(|tcx| { |
| report_maybe_different(f, values.expected.sort_string(tcx), |
| values.found.sort_string(tcx)) |
| }), |
| Traits(values) => ty::tls::with(|tcx| { |
| report_maybe_different(f, |
| format!("trait `{}`", |
| tcx.item_path_str(values.expected)), |
| format!("trait `{}`", |
| tcx.item_path_str(values.found))) |
| }), |
| IntMismatch(ref values) => { |
| write!(f, "expected `{:?}`, found `{:?}`", |
| values.expected, |
| values.found) |
| } |
| FloatMismatch(ref values) => { |
| write!(f, "expected `{:?}`, found `{:?}`", |
| values.expected, |
| values.found) |
| } |
| VariadicMismatch(ref values) => { |
| write!(f, "expected {} fn, found {} function", |
| if values.expected { "variadic" } else { "non-variadic" }, |
| if values.found { "variadic" } else { "non-variadic" }) |
| } |
| ProjectionMismatched(ref values) => ty::tls::with(|tcx| { |
| write!(f, "expected {}, found {}", |
| tcx.item_path_str(values.expected), |
| tcx.item_path_str(values.found)) |
| }), |
| ProjectionBoundsLength(ref values) => { |
| write!(f, "expected {} associated type bindings, found {}", |
| values.expected, |
| values.found) |
| }, |
| ExistentialMismatch(ref values) => { |
| report_maybe_different(f, format!("trait `{}`", values.expected), |
| format!("trait `{}`", values.found)) |
| } |
| OldStyleLUB(ref err) => { |
| write!(f, "{}", err) |
| } |
| } |
| } |
| } |
| |
| impl<'a, 'gcx, 'lcx, 'tcx> ty::TyS<'tcx> { |
| pub fn sort_string(&self, tcx: TyCtxt<'a, 'gcx, 'lcx>) -> String { |
| match self.sty { |
| ty::TyBool | ty::TyChar | ty::TyInt(_) | |
| ty::TyUint(_) | ty::TyFloat(_) | ty::TyStr | ty::TyNever => self.to_string(), |
| ty::TyTuple(ref tys) if tys.is_empty() => self.to_string(), |
| |
| ty::TyAdt(def, _) => format!("{} `{}`", def.descr(), tcx.item_path_str(def.did)), |
| ty::TyForeign(def_id) => format!("extern type `{}`", tcx.item_path_str(def_id)), |
| ty::TyArray(_, n) => { |
| match n.assert_usize(tcx) { |
| Some(n) => format!("array of {} elements", n), |
| None => "array".to_string(), |
| } |
| } |
| ty::TySlice(_) => "slice".to_string(), |
| ty::TyRawPtr(_) => "*-ptr".to_string(), |
| ty::TyRef(region, ty, mutbl) => { |
| let tymut = ty::TypeAndMut { ty, mutbl }; |
| let tymut_string = tymut.to_string(); |
| if tymut_string == "_" || //unknown type name, |
| tymut_string.len() > 10 || //name longer than saying "reference", |
| region.to_string() != "" //... or a complex type |
| { |
| format!("{}reference", match mutbl { |
| hir::Mutability::MutMutable => "mutable ", |
| _ => "" |
| }) |
| } else { |
| format!("&{}", tymut_string) |
| } |
| } |
| ty::TyFnDef(..) => "fn item".to_string(), |
| ty::TyFnPtr(_) => "fn pointer".to_string(), |
| ty::TyDynamic(ref inner, ..) => { |
| inner.principal().map_or_else(|| "trait".to_string(), |
| |p| format!("trait {}", tcx.item_path_str(p.def_id()))) |
| } |
| ty::TyClosure(..) => "closure".to_string(), |
| ty::TyGenerator(..) => "generator".to_string(), |
| ty::TyGeneratorWitness(..) => "generator witness".to_string(), |
| ty::TyTuple(..) => "tuple".to_string(), |
| ty::TyInfer(ty::TyVar(_)) => "inferred type".to_string(), |
| ty::TyInfer(ty::IntVar(_)) => "integral variable".to_string(), |
| ty::TyInfer(ty::FloatVar(_)) => "floating-point variable".to_string(), |
| ty::TyInfer(ty::CanonicalTy(_)) | |
| ty::TyInfer(ty::FreshTy(_)) => "skolemized type".to_string(), |
| ty::TyInfer(ty::FreshIntTy(_)) => "skolemized integral type".to_string(), |
| ty::TyInfer(ty::FreshFloatTy(_)) => "skolemized floating-point type".to_string(), |
| ty::TyProjection(_) => "associated type".to_string(), |
| ty::TyParam(ref p) => { |
| if p.is_self() { |
| "Self".to_string() |
| } else { |
| "type parameter".to_string() |
| } |
| } |
| ty::TyAnon(..) => "anonymized type".to_string(), |
| ty::TyError => "type error".to_string(), |
| } |
| } |
| } |
| |
| impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> { |
| pub fn note_and_explain_type_err(self, |
| db: &mut DiagnosticBuilder, |
| err: &TypeError<'tcx>, |
| sp: Span) { |
| use self::TypeError::*; |
| |
| match err.clone() { |
| Sorts(values) => { |
| let expected_str = values.expected.sort_string(self); |
| let found_str = values.found.sort_string(self); |
| if expected_str == found_str && expected_str == "closure" { |
| db.note("no two closures, even if identical, have the same type"); |
| db.help("consider boxing your closure and/or using it as a trait object"); |
| } |
| }, |
| OldStyleLUB(err) => { |
| db.note("this was previously accepted by the compiler but has been phased out"); |
| db.note("for more information, see https://github.com/rust-lang/rust/issues/45852"); |
| |
| self.note_and_explain_type_err(db, &err, sp); |
| } |
| CyclicTy(ty) => { |
| // Watch out for various cases of cyclic types and try to explain. |
| if ty.is_closure() || ty.is_generator() { |
| db.note("closures cannot capture themselves or take themselves as argument;\n\ |
| this error may be the result of a recent compiler bug-fix,\n\ |
| see https://github.com/rust-lang/rust/issues/46062 for more details"); |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
