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Substitute erased lifetimes on bad placeholder type

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Fix #82455.
This commit is contained in:
Esteban Küber 2021-02-24 12:21:18 -08:00
parent 3e826bb112
commit 5ad6088827
3 changed files with 44 additions and 2 deletions
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12
compiler/rustc_typeck/src/collect.rs
View File

@ -371,6 +371,11 @@ fn ct_infer(
span: Span,
) -> &'tcx Const<'tcx> {
bad_placeholder_type(self.tcx(), vec![span]).emit();
// Typeck doesn't expect erased regions to be returned from `type_of`.
let ty = self.tcx.fold_regions(ty, &mut false, |r, _| match r {
ty::ReErased => self.tcx.lifetimes.re_static,
_ => r,
});
self.tcx().const_error(ty)
}
@ -1647,6 +1652,12 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
match get_infer_ret_ty(&sig.decl.output) {
Some(ty) => {
let fn_sig = tcx.typeck(def_id).liberated_fn_sigs()[hir_id];
// Typeck doesn't expect erased regions to be returned from `type_of`.
let fn_sig = tcx.fold_regions(fn_sig, &mut false, |r, _| match r {
ty::ReErased => tcx.lifetimes.re_static,
_ => r,
});
let mut visitor = PlaceholderHirTyCollector::default();
visitor.visit_ty(ty);
let mut diag = bad_placeholder_type(tcx, visitor.0);
@ -1675,6 +1686,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
}
}
diag.emit();
ty::Binder::bind(fn_sig)
}
None => AstConv::ty_of_fn(

12
src/test/ui/typeck/typeck_type_placeholder_item.rs
View File

@ -208,3 +208,15 @@ impl Qux for Struct {
const D: _ = 42;
//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
}
fn map<T>(_: fn() -> Option<&'static T>) -> Option<T> {
None
}
fn value() -> Option<&'static _> {
//~^ ERROR the type placeholder `_` is not allowed within types on item signatures
Option::<&'static u8>::None
}
const _: Option<_> = map(value);
//~^ ERROR the type placeholder `_` is not allowed within types on item signatures

22
src/test/ui/typeck/typeck_type_placeholder_item.stderr
View File

@ -158,7 +158,7 @@ LL | fn test11(x: &usize) -> &_ {
| -^
| ||
| |not allowed in type signatures
| help: replace with the correct return type: `&&usize`
| help: replace with the correct return type: `&'static &'static usize`
error[E0121]: the type placeholder `_` is not allowed within types on item signatures
--> $DIR/typeck_type_placeholder_item.rs:52:52
@ -410,6 +410,24 @@ error[E0121]: the type placeholder `_` is not allowed within types on item signa
LL | type Y = impl Trait<_>;
| ^ not allowed in type signatures
error[E0121]: the type placeholder `_` is not allowed within types on item signatures
--> $DIR/typeck_type_placeholder_item.rs:216:31
|
LL | fn value() -> Option<&'static _> {
| ----------------^-
| | |
| | not allowed in type signatures
| help: replace with the correct return type: `Option<&'static u8>`
error[E0121]: the type placeholder `_` is not allowed within types on item signatures
--> $DIR/typeck_type_placeholder_item.rs:221:10
|
LL | const _: Option<_> = map(value);
| ^^^^^^^^^
| |
| not allowed in type signatures
| help: replace `_` with the correct type: `Option<u8>`
error[E0121]: the type placeholder `_` is not allowed within types on item signatures
--> $DIR/typeck_type_placeholder_item.rs:140:31
|
@ -614,7 +632,7 @@ LL | const D: _ = 42;
| not allowed in type signatures
| help: replace `_` with the correct type: `i32`
error: aborting due to 67 previous errors
error: aborting due to 69 previous errors
Some errors have detailed explanations: E0121, E0282, E0403.
For more information about an error, try `rustc --explain E0121`.