Rollup merge of - compiler-errors:ambig, r=oli-obk

only downgrade selection Error -> Ambiguous if type error is in predicate

That is, we don't care if there's a TypeError type in the ParamEnv.

Fixes 
This commit is contained in:
Dylan DPC 2022-04-15 20:50:46 +02:00 committed by GitHub
commit 747829428b
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5 changed files with 25 additions and 27 deletions

@ -231,8 +231,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// `Err(Unimplemented)` to `Ok(None)`. This helps us avoid
// emitting additional spurious errors, since we're guaranteed
// to have emitted at least one.
if stack.obligation.references_error() {
debug!("no results for error type, treating as ambiguous");
if stack.obligation.predicate.references_error() {
debug!(?stack.obligation.predicate, "found error type in predicate, treating as ambiguous");
return Ok(None);
}
return Err(Unimplemented);

@ -8,15 +8,7 @@ where
//~^ ERROR cannot find type `T` in this scope
//~| NOTE not found in this scope
{
// The part where it claims that there is no method named `len` is a bug. Feel free to fix it.
// This test is intended to ensure that a different bug, where it claimed
// that `v` was a function, does not regress.
fn method(v: Vec<u8>) { v.len(); }
//~^ ERROR type annotations needed
//~| NOTE cannot infer type
//~| NOTE type must be known at this point
//~| ERROR no method named `len`
//~| NOTE private field, not a method
}
fn main() {}

@ -12,21 +12,6 @@ error[E0412]: cannot find type `T` in this scope
LL | T: Copy,
| ^ not found in this scope
error[E0282]: type annotations needed
--> $DIR/fn-help-with-err-generic-is-not-function.rs:14:31
|
LL | fn method(v: Vec<u8>) { v.len(); }
| ^^^ cannot infer type
|
= note: type must be known at this point
error: aborting due to 2 previous errors
error[E0599]: no method named `len` found for struct `Vec<u8>` in the current scope
--> $DIR/fn-help-with-err-generic-is-not-function.rs:14:31
|
LL | fn method(v: Vec<u8>) { v.len(); }
| ^^^ private field, not a method
error: aborting due to 4 previous errors
Some errors have detailed explanations: E0282, E0412, E0599.
For more information about an error, try `rustc --explain E0282`.
For more information about this error, try `rustc --explain E0412`.

@ -0,0 +1,9 @@
fn foo()
where
T: Send,
//~^ cannot find type `T` in this scope
{
let s = "abc".to_string();
}
fn main() {}

@ -0,0 +1,12 @@
error[E0412]: cannot find type `T` in this scope
--> $DIR/autoderef-with-param-env-error.rs:3:5
|
LL | fn foo()
| - help: you might be missing a type parameter: `<T>`
LL | where
LL | T: Send,
| ^ not found in this scope
error: aborting due to previous error
For more information about this error, try `rustc --explain E0412`.