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Rollup merge of rust-lang#106309 - compiler-errors:prefer-non-err-can…
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…didates, r=oli-obk

Prefer non-`[type error]` candidates during selection

Fixes rust-lang#102130
Fixes rust-lang#106351

r? types

note: Alternatively we could filter out error where-clauses during param-env construction? But we still need to filter out impls with errors during `match_impl`, I think.
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compiler-errors authored Jan 9, 2023
2 parents 1e81ca3 + db6d3b3 commit 500261f
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Showing 12 changed files with 58 additions and 66 deletions.
4 changes: 3 additions & 1 deletion compiler/rustc_middle/src/ty/_match.rs
Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,9 @@ impl<'tcx> TypeRelation<'tcx> for Match<'tcx> {
Err(TypeError::Sorts(relate::expected_found(self, a, b)))
}

(&ty::Error(_), _) | (_, &ty::Error(_)) => Ok(self.tcx().ty_error()),
(&ty::Error(guar), _) | (_, &ty::Error(guar)) => {
Ok(self.tcx().ty_error_with_guaranteed(guar))
}

_ => relate::super_relate_tys(self, a, b),
}
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2 changes: 1 addition & 1 deletion compiler/rustc_middle/src/ty/relate.rs
Original file line number Diff line number Diff line change
Expand Up @@ -414,7 +414,7 @@ pub fn super_relate_tys<'tcx, R: TypeRelation<'tcx>>(
bug!("bound types encountered in super_relate_tys")
}

(&ty::Error(_), _) | (_, &ty::Error(_)) => Ok(tcx.ty_error()),
(&ty::Error(guar), _) | (_, &ty::Error(guar)) => Ok(tcx.ty_error_with_guaranteed(guar)),

(&ty::Never, _)
| (&ty::Char, _)
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Original file line number Diff line number Diff line change
Expand Up @@ -174,7 +174,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
.param_env
.caller_bounds()
.iter()
.filter_map(|o| o.to_opt_poly_trait_pred());
.filter_map(|p| p.to_opt_poly_trait_pred())
.filter(|p| !p.references_error());

// Micro-optimization: filter out predicates relating to different traits.
let matching_bounds =
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3 changes: 3 additions & 0 deletions compiler/rustc_trait_selection/src/traits/select/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2377,6 +2377,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let impl_substs = self.infcx.fresh_substs_for_item(obligation.cause.span, impl_def_id);

let impl_trait_ref = impl_trait_ref.subst(self.tcx(), impl_substs);
if impl_trait_ref.references_error() {
return Err(());
}

debug!(?impl_trait_ref);

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2 changes: 1 addition & 1 deletion src/test/ui/c-variadic/issue-86053-1.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
// error-pattern:unexpected `self` parameter in function
// error-pattern:`...` must be the last argument of a C-variadic function
// error-pattern:cannot find type `F` in this scope
// error-pattern:in type `&'a &'b usize`, reference has a longer lifetime than the data it references


#![feature(c_variadic)]
#![crate_type="lib"]
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22 changes: 2 additions & 20 deletions src/test/ui/c-variadic/issue-86053-1.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -76,24 +76,6 @@ help: you might be missing a type parameter
LL | fn ordering4 < 'a , 'b, F > ( a : , self , self , self ,
| +++

error[E0491]: in type `&'a &'b usize`, reference has a longer lifetime than the data it references
--> $DIR/issue-86053-1.rs:11:52
|
LL | self , ... , self , self , ... ) where F : FnOnce ( & 'a & 'b usize ) {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: the pointer is valid for the lifetime `'a` as defined here
--> $DIR/issue-86053-1.rs:10:16
|
LL | fn ordering4 < 'a , 'b > ( a : , self , self , self ,
| ^^
note: but the referenced data is only valid for the lifetime `'b` as defined here
--> $DIR/issue-86053-1.rs:10:21
|
LL | fn ordering4 < 'a , 'b > ( a : , self , self , self ,
| ^^

error: aborting due to 12 previous errors
error: aborting due to 11 previous errors

Some errors have detailed explanations: E0412, E0491.
For more information about an error, try `rustc --explain E0412`.
For more information about this error, try `rustc --explain E0412`.
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ LL | Condition<{ LHS <= RHS }>: True
= help: use `#![feature(generic_const_exprs)]` to allow generic const expressions

error: generic parameters may not be used in const operations
--> $DIR/issue-72787.rs:25:25
--> $DIR/issue-72787.rs:23:25
|
LL | IsLessOrEqual<{ 8 - I }, { 8 - J }>: True,
| ^ cannot perform const operation using `I`
Expand All @@ -26,50 +26,13 @@ LL | IsLessOrEqual<{ 8 - I }, { 8 - J }>: True,
= help: use `#![feature(generic_const_exprs)]` to allow generic const expressions

error: generic parameters may not be used in const operations
--> $DIR/issue-72787.rs:25:36
--> $DIR/issue-72787.rs:23:36
|
LL | IsLessOrEqual<{ 8 - I }, { 8 - J }>: True,
| ^ cannot perform const operation using `J`
|
= help: const parameters may only be used as standalone arguments, i.e. `J`
= help: use `#![feature(generic_const_exprs)]` to allow generic const expressions

error[E0283]: type annotations needed: cannot satisfy `IsLessOrEqual<I, 8>: True`
--> $DIR/issue-72787.rs:21:26
|
LL | IsLessOrEqual<I, 8>: True,
| ^^^^
|
note: multiple `impl`s or `where` clauses satisfying `IsLessOrEqual<I, 8>: True` found
--> $DIR/issue-72787.rs:10:1
|
LL | impl<const LHS: u32, const RHS: u32> True for IsLessOrEqual<LHS, RHS> where
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
LL | IsLessOrEqual<I, 8>: True,
| ^^^^
...
LL | IsLessOrEqual<{ 8 - I }, { 8 - J }>: True,
| ^^^^

error[E0283]: type annotations needed: cannot satisfy `IsLessOrEqual<I, 8>: True`
--> $DIR/issue-72787.rs:21:26
|
LL | IsLessOrEqual<I, 8>: True,
| ^^^^
|
note: multiple `impl`s or `where` clauses satisfying `IsLessOrEqual<I, 8>: True` found
--> $DIR/issue-72787.rs:10:1
|
LL | impl<const LHS: u32, const RHS: u32> True for IsLessOrEqual<LHS, RHS> where
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
LL | IsLessOrEqual<I, 8>: True,
| ^^^^
...
LL | IsLessOrEqual<{ 8 - I }, { 8 - J }>: True,
| ^^^^

error: aborting due to 6 previous errors
error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0283`.
2 changes: 0 additions & 2 deletions src/test/ui/const-generics/generic_const_exprs/issue-72787.rs
Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,6 @@ struct S<const I: u32, const J: u32>;
impl<const I: u32, const J: u32> S<I, J>
where
IsLessOrEqual<I, 8>: True,
//[min]~^ Error type annotations needed
//[min]~| Error type annotations needed
IsLessOrEqual<J, 8>: True,
IsLessOrEqual<{ 8 - I }, { 8 - J }>: True,
//[min]~^ Error generic parameters may not be used in const operations
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9 changes: 9 additions & 0 deletions src/test/ui/traits/ignore-err-impls.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
pub struct S;

trait Generic<T> {}

impl<'a, T> Generic<&'a T> for S {}
impl Generic<Type> for S {}
//~^ ERROR cannot find type `Type` in this scope

fn main() {}
11 changes: 11 additions & 0 deletions src/test/ui/traits/ignore-err-impls.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
error[E0412]: cannot find type `Type` in this scope
--> $DIR/ignore-err-impls.rs:6:14
|
LL | impl Generic<Type> for S {}
| - ^^^^ not found in this scope
| |
| help: you might be missing a type parameter: `<Type>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0412`.
14 changes: 14 additions & 0 deletions src/test/ui/where-clauses/ignore-err-clauses.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
use std::ops::Add;

fn dbl<T>(x: T) -> <T as Add>::Output
where
T: Copy + Add,
UUU: Copy,
//~^ ERROR cannot find type `UUU` in this scope
{
x + x
}

fn main() {
println!("{}", dbl(3));
}
9 changes: 9 additions & 0 deletions src/test/ui/where-clauses/ignore-err-clauses.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
error[E0412]: cannot find type `UUU` in this scope
--> $DIR/ignore-err-clauses.rs:6:5
|
LL | UUU: Copy,
| ^^^ not found in this scope

error: aborting due to previous error

For more information about this error, try `rustc --explain E0412`.

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