Auto merge of #16935 - Nilstrieb:dont-panic, r=HKalbasi
Handle panicking like rustc CTFE does
Instead of using `core::fmt::format` to format panic messages, which may in turn panic too and cause recursive panics and other messy things, redirect `panic_fmt` to `const_panic_fmt` like CTFE, which in turn goes to `panic_display` and does the things normally. See the tests for the full call stack.
The tests don't work yet, I probably missed something in minicore.
fixes #16907 in my local testing, I also need to add a test for it
diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs
index 035991b..045ffb4 100644
--- a/crates/hir-ty/src/mir/eval.rs
+++ b/crates/hir-ty/src/mir/eval.rs
@@ -2356,7 +2356,7 @@
fn exec_fn_with_args(
&mut self,
- def: FunctionId,
+ mut def: FunctionId,
args: &[IntervalAndTy],
generic_args: Substitution,
locals: &Locals,
@@ -2374,6 +2374,9 @@
)? {
return Ok(None);
}
+ if let Some(redirect_def) = self.detect_and_redirect_special_function(def)? {
+ def = redirect_def;
+ }
let arg_bytes = args.iter().map(|it| IntervalOrOwned::Borrowed(it.interval));
match self.get_mir_or_dyn_index(def, generic_args.clone(), locals, span)? {
MirOrDynIndex::Dyn(self_ty_idx) => {
diff --git a/crates/hir-ty/src/mir/eval/shim.rs b/crates/hir-ty/src/mir/eval/shim.rs
index 628a1fe..d4d6691 100644
--- a/crates/hir-ty/src/mir/eval/shim.rs
+++ b/crates/hir-ty/src/mir/eval/shim.rs
@@ -13,7 +13,7 @@
name, pad16, static_lifetime, Address, AdtId, Arc, BuiltinType, Evaluator, FunctionId,
HasModule, HirDisplay, Interned, InternedClosure, Interner, Interval, IntervalAndTy,
IntervalOrOwned, ItemContainerId, LangItem, Layout, Locals, Lookup, MirEvalError, MirSpan,
- ModPath, Mutability, Result, Substitution, Ty, TyBuilder, TyExt,
+ Mutability, Result, Substitution, Ty, TyBuilder, TyExt,
};
mod simd;
@@ -158,6 +158,25 @@
Ok(false)
}
+ pub(super) fn detect_and_redirect_special_function(
+ &mut self,
+ def: FunctionId,
+ ) -> Result<Option<FunctionId>> {
+ // `PanicFmt` is redirected to `ConstPanicFmt`
+ if let Some(LangItem::PanicFmt) = self.db.lang_attr(def.into()) {
+ let resolver =
+ self.db.crate_def_map(self.crate_id).crate_root().resolver(self.db.upcast());
+
+ let Some(hir_def::lang_item::LangItemTarget::Function(const_panic_fmt)) =
+ self.db.lang_item(resolver.krate(), LangItem::ConstPanicFmt)
+ else {
+ not_supported!("const_panic_fmt lang item not found or not a function");
+ };
+ return Ok(Some(const_panic_fmt));
+ }
+ Ok(None)
+ }
+
/// Clone has special impls for tuples and function pointers
fn exec_clone(
&mut self,
@@ -291,9 +310,14 @@
use LangItem::*;
let candidate = self.db.lang_attr(def.into())?;
// We want to execute these functions with special logic
- if [PanicFmt, BeginPanic, SliceLen, DropInPlace].contains(&candidate) {
+ // `PanicFmt` is not detected here as it's redirected later.
+ if [BeginPanic, SliceLen, DropInPlace].contains(&candidate) {
return Some(candidate);
}
+ if self.db.attrs(def.into()).by_key("rustc_const_panic_str").exists() {
+ // `#[rustc_const_panic_str]` is treated like `lang = "begin_panic"` by rustc CTFE.
+ return Some(LangItem::BeginPanic);
+ }
None
}
@@ -309,43 +333,6 @@
let mut args = args.iter();
match it {
BeginPanic => Err(MirEvalError::Panic("<unknown-panic-payload>".to_owned())),
- PanicFmt => {
- let message = (|| {
- let resolver = self
- .db
- .crate_def_map(self.crate_id)
- .crate_root()
- .resolver(self.db.upcast());
- let Some(format_fn) = resolver.resolve_path_in_value_ns_fully(
- self.db.upcast(),
- &hir_def::path::Path::from_known_path_with_no_generic(
- ModPath::from_segments(
- hir_expand::mod_path::PathKind::Abs,
- [name![std], name![fmt], name![format]],
- ),
- ),
- ) else {
- not_supported!("std::fmt::format not found");
- };
- let hir_def::resolver::ValueNs::FunctionId(format_fn) = format_fn else {
- not_supported!("std::fmt::format is not a function")
- };
- let interval = self.interpret_mir(
- self.db
- .mir_body(format_fn.into())
- .map_err(|e| MirEvalError::MirLowerError(format_fn, e))?,
- args.map(|x| IntervalOrOwned::Owned(x.clone())),
- )?;
- let message_string = interval.get(self)?;
- let addr =
- Address::from_bytes(&message_string[self.ptr_size()..2 * self.ptr_size()])?;
- let size = from_bytes!(usize, message_string[2 * self.ptr_size()..]);
- Ok(std::string::String::from_utf8_lossy(self.read_memory(addr, size)?)
- .into_owned())
- })()
- .unwrap_or_else(|e| format!("Failed to render panic format args: {e:?}"));
- Err(MirEvalError::Panic(message))
- }
SliceLen => {
let arg = args.next().ok_or(MirEvalError::InternalError(
"argument of <[T]>::len() is not provided".into(),
diff --git a/crates/ide/src/hover/tests.rs b/crates/ide/src/hover/tests.rs
index 4451e31..466e557 100644
--- a/crates/ide/src/hover/tests.rs
+++ b/crates/ide/src/hover/tests.rs
@@ -5106,6 +5106,32 @@
}
#[test]
+fn hover_const_value() {
+ check(
+ r#"
+pub enum AA {
+ BB,
+}
+const CONST: AA = AA::BB;
+pub fn the_function() -> AA {
+ CON$0ST
+}
+"#,
+ expect![[r#"
+ *CONST*
+
+ ```rust
+ test
+ ```
+
+ ```rust
+ const CONST: AA = BB
+ ```
+ "#]],
+ );
+}
+
+#[test]
fn array_repeat_exp() {
check(
r#"
