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Auto merge of #100865 - compiler-errors:parent-substs-still, r=cjgillot

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Don't drop parent substs when we have no generic parameters in `create_substs_for_ast_path`

This bug is being shadowed by an explicit check for `generics.params.is_empty()` in the only parent caller that could trigger it (`create_substs_for_associated_item`). I triggered it on another branch where I'm messing around with astconv stuff.

Also, the second commit simplifies `create_substs_for_associated_item`. Removing that explicit check I mentioned above^ and also the special case call to `Astconv::prohibit_generics` causes the UI test `src/test/ui/structs/struct-path-associated-type.stderr` to change, but I think that it's clearer now. The suggestion to remove the generics is actually useful.
This commit is contained in:
bors 2022-09-25 12:00:37 +00:00
commit 4652f5eb25
5 changed files with 34 additions and 33 deletions
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31
compiler/rustc_typeck/src/astconv/mod.rs
View file

@ -365,7 +365,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
// here and so associated type bindings will be handled regardless of whether there are any
// non-`Self` generic parameters.
if generics.params.is_empty() {
return (tcx.intern_substs(&[]), arg_count);
return (tcx.intern_substs(parent_substs), arg_count);
}
struct SubstsForAstPathCtxt<'a, 'tcx> {
@ -586,7 +586,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
pub(crate) fn create_substs_for_associated_item(
&self,
tcx: TyCtxt<'tcx>,
span: Span,
item_def_id: DefId,
item_segment: &hir::PathSegment<'_>,
@ -596,22 +595,16 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
"create_substs_for_associated_item(span: {:?}, item_def_id: {:?}, item_segment: {:?}",
span, item_def_id, item_segment
);
if tcx.generics_of(item_def_id).params.is_empty() {
self.prohibit_generics(slice::from_ref(item_segment).iter(), |_| {});
parent_substs
} else {
self.create_substs_for_ast_path(
span,
item_def_id,
parent_substs,
item_segment,
item_segment.args(),
item_segment.infer_args,
None,
)
.0
}
self.create_substs_for_ast_path(
span,
item_def_id,
parent_substs,
item_segment,
item_segment.args(),
item_segment.infer_args,
None,
)
.0
}
/// Instantiates the path for the given trait reference, assuming that it's
@ -1121,7 +1114,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
};
let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item(
tcx,
path_span,
assoc_item.def_id,
&item_segment,
@ -2100,7 +2092,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
self.ast_path_to_mono_trait_ref(span, trait_def_id, self_ty, trait_segment, false);
let item_substs = self.create_substs_for_associated_item(
tcx,
span,
item_def_id,
item_segment,

1
compiler/rustc_typeck/src/check/fn_ctxt/mod.rs
View file

@ -276,7 +276,6 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
self,
self.tcx,
span,
item_def_id,
item_segment,

1
compiler/rustc_typeck/src/collect.rs
View file

@ -430,7 +430,6 @@ impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> {
if let Some(trait_ref) = poly_trait_ref.no_bound_vars() {
let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
self,
self.tcx,
span,
item_def_id,
item_segment,

4
src/test/ui/structs/struct-path-associated-type.rs
View file

@ -13,7 +13,7 @@ fn f<T: Tr>() {
//~^ ERROR expected struct, variant or union type, found associated type
let z = T::A::<u8> {};
//~^ ERROR expected struct, variant or union type, found associated type
//~| ERROR type arguments are not allowed on this type
//~| ERROR this associated type takes 0 generic arguments but 1 generic argument was supplied
match S {
T::A {} => {}
//~^ ERROR expected struct, variant or union type, found associated type
@ -22,7 +22,7 @@ fn f<T: Tr>() {
fn g<T: Tr<A = S>>() {
let s = T::A {}; // OK
let z = T::A::<u8> {}; //~ ERROR type arguments are not allowed on this type
let z = T::A::<u8> {}; //~ ERROR this associated type takes 0 generic arguments but 1 generic argument was supplied
match S {
T::A {} => {} // OK
}

30
src/test/ui/structs/struct-path-associated-type.stderr
View file

@ -4,13 +4,19 @@ error[E0071]: expected struct, variant or union type, found associated type
LL | let s = T::A {};
| ^^^^ not a struct
error[E0109]: type arguments are not allowed on this type
--> $DIR/struct-path-associated-type.rs:14:20
error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
--> $DIR/struct-path-associated-type.rs:14:16
|
LL | let z = T::A::<u8> {};
| - ^^ type argument not allowed
| ^------ help: remove these generics
| |
| not allowed on this type
| expected 0 generic arguments
|
note: associated type defined here, with 0 generic parameters
--> $DIR/struct-path-associated-type.rs:4:10
|
LL | type A;
| ^
error[E0071]: expected struct, variant or union type, found associated type
--> $DIR/struct-path-associated-type.rs:14:13
@ -24,13 +30,19 @@ error[E0071]: expected struct, variant or union type, found associated type
LL | T::A {} => {}
| ^^^^ not a struct
error[E0109]: type arguments are not allowed on this type
--> $DIR/struct-path-associated-type.rs:25:20
error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
--> $DIR/struct-path-associated-type.rs:25:16
|
LL | let z = T::A::<u8> {};
| - ^^ type argument not allowed
| ^------ help: remove these generics
| |
| not allowed on this type
| expected 0 generic arguments
|
note: associated type defined here, with 0 generic parameters
--> $DIR/struct-path-associated-type.rs:4:10
|
LL | type A;
| ^
error[E0223]: ambiguous associated type
--> $DIR/struct-path-associated-type.rs:32:13
@ -52,5 +64,5 @@ LL | S::A {} => {}
error: aborting due to 8 previous errors
Some errors have detailed explanations: E0071, E0109, E0223.
Some errors have detailed explanations: E0071, E0107, E0223.
For more information about an error, try `rustc --explain E0071`.