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Add more context for type parameters

This commit is contained in:
Esteban Küber 2019-12-11 17:06:24 -08:00
parent 45550ef2ff
commit da023c0c6f
41 changed files with 128 additions and 51 deletions
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42
src/librustc/infer/error_reporting/need_type_info.rs
View File

@ -9,6 +9,7 @@ use syntax::source_map::DesugaringKind;
use syntax::symbol::kw;
use syntax_pos::Span;
use errors::{Applicability, DiagnosticBuilder};
use std::borrow::Cow;
use rustc_error_codes::*;
@ -113,6 +114,7 @@ fn closure_return_type_suggestion(
err: &mut DiagnosticBuilder<'_>,
output: &FunctionRetTy,
body: &Body,
descr: &str,
name: &str,
ret: &str,
) {
@ -136,7 +138,7 @@ fn closure_return_type_suggestion(
suggestion,
Applicability::HasPlaceholders,
);
err.span_label(span, InferCtxt::missing_type_msg(&name));
err.span_label(span, InferCtxt::missing_type_msg(&name, &descr));
}
/// Given a closure signature, return a `String` containing a list of all its argument types.
@ -175,13 +177,17 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
&self,
ty: Ty<'tcx>,
highlight: Option<ty::print::RegionHighlightMode>,
) -> (String, Option<Span>) {
) -> (String, Option<Span>, Cow<'static, str>) {
if let ty::Infer(ty::TyVar(ty_vid)) = ty.kind {
let ty_vars = self.type_variables.borrow();
let var_origin = ty_vars.var_origin(ty_vid);
if let TypeVariableOriginKind::TypeParameterDefinition(name) = var_origin.kind {
if name != kw::SelfUpper {
return (name.to_string(), Some(var_origin.span));
return (
name.to_string(),
Some(var_origin.span),
"type parameter".into(),
);
}
}
}
@ -192,7 +198,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
printer.region_highlight_mode = highlight;
}
let _ = ty.print(printer);
(s, None)
(s, None, ty.prefix_string())
}
pub fn need_type_info_err(
@ -203,7 +209,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
error_code: TypeAnnotationNeeded,
) -> DiagnosticBuilder<'tcx> {
let ty = self.resolve_vars_if_possible(&ty);
let (name, name_sp) = self.extract_type_name(&ty, None);
let (name, name_sp, descr) = self.extract_type_name(&ty, None);
let mut local_visitor = FindLocalByTypeVisitor::new(&self, ty, &self.tcx.hir());
let ty_to_string = |ty: Ty<'tcx>| -> String {
@ -308,6 +314,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
&mut err,
&decl.output,
&body,
&descr,
&name,
&ret,
);
@ -427,7 +434,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
span_label.label.is_some() && span_label.span == span
}) && local_visitor.found_arg_pattern.is_none()
{ // Avoid multiple labels pointing at `span`.
err.span_label(span, InferCtxt::missing_type_msg(&name));
err.span_label(span, InferCtxt::missing_type_msg(&name, &descr));
}
err
@ -468,10 +475,15 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
);
} else {
let sig = self.tcx.fn_sig(did);
err.span_label(e.span, &format!(
"this method call resolves to `{:?}`",
sig.output().skip_binder(),
));
let bound_output = sig.output();
let output = bound_output.skip_binder();
err.span_label(e.span, &format!("this method call resolves to `{:?}`", output));
let kind = &output.kind;
if let ty::Projection(proj) | ty::UnnormalizedProjection(proj) = kind {
if let Some(span) = self.tcx.hir().span_if_local(proj.item_def_id) {
err.span_label(span, &format!("`{:?}` defined here", output));
}
}
}
}
}
@ -484,19 +496,19 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
ty: Ty<'tcx>,
) -> DiagnosticBuilder<'tcx> {
let ty = self.resolve_vars_if_possible(&ty);
let name = self.extract_type_name(&ty, None).0;
let (name, _, descr) = self.extract_type_name(&ty, None);
let mut err = struct_span_err!(
self.tcx.sess, span, E0698, "type inside {} must be known in this context", kind,
);
err.span_label(span, InferCtxt::missing_type_msg(&name));
err.span_label(span, InferCtxt::missing_type_msg(&name, &descr));
err
}
fn missing_type_msg(type_name: &str) -> String {
fn missing_type_msg(type_name: &str, descr: &str) -> Cow<'static, str>{
if type_name == "_" {
"cannot infer type".to_owned()
"cannot infer type".into()
} else {
format!("cannot infer type for `{}`", type_name)
format!("cannot infer type for {} `{}`", descr, type_name).into()
}
}
}

4
src/test/ui/associated-types/associated-types-overridden-binding.stderr
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@ -4,7 +4,7 @@ error[E0284]: type annotations needed
LL | trait Foo: Iterator<Item = i32> {}
| ------------------------------- required by `Foo`
LL | trait Bar: Foo<Item = u32> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for `Self`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `Self`
|
= note: cannot resolve `<Self as std::iter::Iterator>::Item == i32`
@ -14,7 +14,7 @@ error[E0284]: type annotations needed
LL | trait I32Iterator = Iterator<Item = i32>;
| ----------------------------------------- required by `I32Iterator`
LL | trait U32Iterator = I32Iterator<Item = u32>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for `Self`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `Self`
|
= note: cannot resolve `<Self as std::iter::Iterator>::Item == i32`

2
src/test/ui/async-await/unresolved_type_param.rs
View File

@ -8,7 +8,7 @@ async fn bar<T>() -> () {}
async fn foo() {
bar().await;
//~^ ERROR type inside `async fn` body must be known in this context
//~| NOTE cannot infer type for `T`
//~| NOTE cannot infer type for type parameter `T`
//~| NOTE the type is part of the `async fn` body because of this `await`
//~| NOTE in this expansion of desugaring of `await`
}

2
src/test/ui/async-await/unresolved_type_param.stderr
View File

@ -2,7 +2,7 @@ error[E0698]: type inside `async fn` body must be known in this context
--> $DIR/unresolved_type_param.rs:9:5
|
LL | bar().await;
| ^^^ cannot infer type for `T`
| ^^^ cannot infer type for type parameter `T`
|
note: the type is part of the `async fn` body because of this `await`
--> $DIR/unresolved_type_param.rs:9:5

2
src/test/ui/const-generics/cannot-infer-const-args.stderr
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@ -10,7 +10,7 @@ error[E0282]: type annotations needed
--> $DIR/cannot-infer-const-args.rs:9:5
|
LL | foo();
| ^^^ cannot infer type for `fn() -> usize {foo::<_: usize>}`
| ^^^ cannot infer type for fn item `fn() -> usize {foo::<_: usize>}`
error: aborting due to previous error

2
src/test/ui/const-generics/fn-const-param-infer.stderr
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@ -30,7 +30,7 @@ error[E0282]: type annotations needed
--> $DIR/fn-const-param-infer.rs:22:23
|
LL | let _ = Checked::<generic>;
| ^^^^^^^ cannot infer type for `T`
| ^^^^^^^ cannot infer type for type parameter `T`
error[E0308]: mismatched types
--> $DIR/fn-const-param-infer.rs:25:40

4
src/test/ui/consts/issue-64662.stderr
View File

@ -2,13 +2,13 @@ error[E0282]: type annotations needed
--> $DIR/issue-64662.rs:2:9
|
LL | A = foo(),
| ^^^ cannot infer type for `T`
| ^^^ cannot infer type for type parameter `T`
error[E0282]: type annotations needed
--> $DIR/issue-64662.rs:3:9
|
LL | B = foo(),
| ^^^ cannot infer type for `T`
| ^^^ cannot infer type for type parameter `T`
error: aborting due to 2 previous errors

2
src/test/ui/error-codes/E0401.stderr
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@ -36,7 +36,7 @@ error[E0282]: type annotations needed
--> $DIR/E0401.rs:11:5
|
LL | bfnr(x);
| ^^^^ cannot infer type for `U`
| ^^^^ cannot infer type for type parameter `U`
error: aborting due to 4 previous errors

2
src/test/ui/issues/issue-12028.stderr
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@ -2,7 +2,7 @@ error[E0284]: type annotations needed
--> $DIR/issue-12028.rs:27:14
|
LL | self.input_stream(&mut stream);
| ^^^^^^^^^^^^ cannot infer type for `H`
| ^^^^^^^^^^^^ cannot infer type for type parameter `H`
|
= note: cannot resolve `<_ as StreamHasher>::S == <H as StreamHasher>::S`

2
src/test/ui/issues/issue-16966.stderr
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@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/issue-16966.rs:2:5
|
LL | panic!(std::default::Default::default());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for `M`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `M`
|
= note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

2
src/test/ui/issues/issue-17551.stderr
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@ -2,7 +2,7 @@ error[E0282]: type annotations needed for `B<T>`
--> $DIR/issue-17551.rs:6:15
|
LL | let foo = B(marker::PhantomData);
| --- ^ cannot infer type for `T`
| --- ^ cannot infer type for type parameter `T`
| |
| consider giving `foo` the explicit type `B<T>`, where the type parameter `T` is specified

2
src/test/ui/issues/issue-21974.stderr
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@ -11,7 +11,7 @@ LL | | {
LL | | x.foo();
LL | | y.foo();
LL | | }
| |_^ cannot infer type for `&'a T`
| |_^ cannot infer type for reference `&'a T`
|
= note: cannot resolve `&'a T: Foo`

2
src/test/ui/issues/issue-24424.stderr
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@ -5,7 +5,7 @@ LL | trait Trait0<'l0> {}
| ----------------- required by `Trait0`
LL |
LL | impl <'l0, 'l1, T0> Trait1<'l0, T0> for bool where T0 : Trait0<'l0>, T0 : Trait0<'l1> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for `T0`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T0`
|
= note: cannot resolve `T0: Trait0<'l0>`

2
src/test/ui/issues/issue-25368.stderr
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@ -5,7 +5,7 @@ LL | let (tx, rx) = channel();
| -------- consider giving this pattern the explicit type `(std::sync::mpsc::Sender<Foo<T>>, std::sync::mpsc::Receiver<Foo<T>>)`, where the type parameter `T` is specified
...
LL | tx.send(Foo{ foo: PhantomData });
| ^^^ cannot infer type for `T`
| ^^^ cannot infer type for type parameter `T`
error: aborting due to previous error

2
src/test/ui/issues/issue-29147.stderr
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@ -5,7 +5,7 @@ LL | trait Foo { fn xxx(&self); }
| -------------- required by `Foo::xxx`
...
LL | let _ = <S5<_>>::xxx;
| ^^^^^^^^^^^^ cannot infer type for `S5<_>`
| ^^^^^^^^^^^^ cannot infer type for struct `S5<_>`
|
= note: cannot resolve `S5<_>: Foo`

2
src/test/ui/issues/issue-5062.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/issue-5062.rs:1:29
|
LL | fn main() { format!("{:?}", None); }
| ^^^^ cannot infer type for `T`
| ^^^^ cannot infer type for type parameter `T`
error: aborting due to previous error

2
src/test/ui/issues/issue-6458-2.stderr
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@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/issue-6458-2.rs:3:21
|
LL | format!("{:?}", None);
| ^^^^ cannot infer type for `T`
| ^^^^ cannot infer type for type parameter `T`
error: aborting due to previous error

2
src/test/ui/issues/issue-6458-3.stderr
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@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/issue-6458-3.rs:4:5
|
LL | mem::transmute(0);
| ^^^^^^^^^^^^^^ cannot infer type for `U`
| ^^^^^^^^^^^^^^ cannot infer type for type parameter `U`
error: aborting due to previous error

2
src/test/ui/issues/issue-6458.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/issue-6458.rs:9:4
|
LL | foo(TypeWithState(marker::PhantomData));
| ^^^ cannot infer type for `State`
| ^^^ cannot infer type for type parameter `State`
error: aborting due to previous error

2
src/test/ui/issues/issue-65611.stderr
View File

@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | let x = buffer.last().unwrap().0.clone();
| -------^^^^--
| | |
| | cannot infer type for `T`
| | cannot infer type for type parameter `T`
| this method call resolves to `std::option::Option<&T>`
|
= note: type must be known at this point

2
src/test/ui/methods/method-ambig-one-trait-unknown-int-type.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed for `std::vec::Vec<T>`
--> $DIR/method-ambig-one-trait-unknown-int-type.rs:24:17
|
LL | let mut x = Vec::new();
| ----- ^^^^^^^^ cannot infer type for `T`
| ----- ^^^^^^^^ cannot infer type for type parameter `T`
| |
| consider giving `x` the explicit type `std::vec::Vec<T>`, where the type parameter `T` is specified

2
src/test/ui/missing/missing-items/missing-type-parameter.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/missing-type-parameter.rs:4:5
|
LL | foo();
| ^^^ cannot infer type for `X`
| ^^^ cannot infer type for type parameter `X`
error: aborting due to previous error

2
src/test/ui/span/issue-42234-unknown-receiver-type.stderr
View File

@ -4,7 +4,7 @@ error[E0282]: type annotations needed for `std::option::Option<_>`
LL | let x: Option<_> = None;
| - consider giving `x` the explicit type `std::option::Option<_>`, where the type parameter `T` is specified
LL | x.unwrap().method_that_could_exist_on_some_type();
| ^^^^^^ cannot infer type for `T`
| ^^^^^^ cannot infer type for type parameter `T`
|
= note: type must be known at this point

2
src/test/ui/span/type-annotations-needed-expr.stderr
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@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | let _ = (vec![1,2,3]).into_iter().sum() as f64;
| ^^^
| |
| cannot infer type for `S`
| cannot infer type for type parameter `S`
| help: consider specifying the type argument in the method call: `sum::<S>`
|
= note: type must be known at this point

2
src/test/ui/traits/traits-multidispatch-convert-ambig-dest.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/traits-multidispatch-convert-ambig-dest.rs:26:5
|
LL | test(22, std::default::Default::default());
| ^^^^ cannot infer type for `U`
| ^^^^ cannot infer type for type parameter `U`
error: aborting due to previous error

2
src/test/ui/type-inference/or_else-multiple-type-params.stderr
View File

@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | .or_else(|err| {
| ^^^^^^^
| |
| cannot infer type for `F`
| cannot infer type for type parameter `F`
| help: consider specifying the type arguments in the method call: `or_else::<F, O>`
error: aborting due to previous error

2
src/test/ui/type-inference/sort_by_key.stderr
View File

@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | lst.sort_by_key(|&(v, _)| v.iter().sum());
| ^^^^^^^^^^^ --- help: consider specifying the type argument in the method call: `sum::<S>`
| |
| cannot infer type for `K`
| cannot infer type for type parameter `K`
error: aborting due to previous error

16
src/test/ui/type-inference/unbounded-associated-type.rs Normal file
View File

@ -0,0 +1,16 @@
trait T {
type A;
fn foo(&self) -> Self::A {
panic!()
}
}
struct S<X>(std::marker::PhantomData<X>);
impl<X> T for S<X> {
type A = X;
}
fn main() {
S(std::marker::PhantomData).foo(); //~ ERROR type annotations needed
}

15
src/test/ui/type-inference/unbounded-associated-type.stderr Normal file
View File

@ -0,0 +1,15 @@
error[E0282]: type annotations needed
--> $DIR/unbounded-associated-type.rs:15:5
|
LL | type A;
| ------- `<Self as T>::A` defined here
...
LL | S(std::marker::PhantomData).foo();
| ^--------------------------------
| |
| this method call resolves to `<Self as T>::A`
| cannot infer type for type parameter `X`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0282`.

9
src/test/ui/type-inference/unbounded-type-param-in-fn-with-assoc-type.rs Normal file
View File

@ -0,0 +1,9 @@
#[allow(invalid_type_param_default)]
fn foo<T, U = u64>() -> (T, U) {
panic!()
}
fn main() {
foo(); //~ ERROR type annotations needed
}

9
src/test/ui/type-inference/unbounded-type-param-in-fn-with-assoc-type.stderr Normal file
View File

@ -0,0 +1,9 @@
error[E0282]: type annotations needed
--> $DIR/unbounded-type-param-in-fn-with-assoc-type.rs:8:5
|
LL | foo();
| ^^^ cannot infer type for type parameter `T`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0282`.

7
src/test/ui/type-inference/unbounded-type-param-in-fn.rs Normal file
View File

@ -0,0 +1,7 @@
fn foo<T>() -> T {
panic!()
}
fn main() {
foo(); //~ ERROR type annotations needed
}

9
src/test/ui/type-inference/unbounded-type-param-in-fn.stderr Normal file
View File

@ -0,0 +1,9 @@
error[E0282]: type annotations needed
--> $DIR/unbounded-type-param-in-fn.rs:6:5
|
LL | foo();
| ^^^ cannot infer type for type parameter `T`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0282`.

2
src/test/ui/type/type-annotation-needed.stderr
View File

@ -7,7 +7,7 @@ LL | fn foo<T: Into<String>>(x: i32) {}
LL | foo(42);
| ^^^
| |
| cannot infer type for `T`
| cannot infer type for type parameter `T`
| help: consider specifying the type argument in the function call: `foo::<T>`
|
= note: cannot resolve `_: std::convert::Into<std::string::String>`

2
src/test/ui/type/type-check/cannot_infer_local_or_vec.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed for `std::vec::Vec<T>`
--> $DIR/cannot_infer_local_or_vec.rs:2:13
|
LL | let x = vec![];
| - ^^^^^^ cannot infer type for `T`
| - ^^^^^^ cannot infer type for type parameter `T`
| |
| consider giving `x` the explicit type `std::vec::Vec<T>`, where the type parameter `T` is specified
|

2
src/test/ui/type/type-check/cannot_infer_local_or_vec_in_tuples.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed for `(std::vec::Vec<T>,)`
--> $DIR/cannot_infer_local_or_vec_in_tuples.rs:2:18
|
LL | let (x, ) = (vec![], );
| ----- ^^^^^^ cannot infer type for `T`
| ----- ^^^^^^ cannot infer type for type parameter `T`
| |
| consider giving this pattern the explicit type `(std::vec::Vec<T>,)`, where the type parameter `T` is specified
|

2
src/test/ui/type/type-check/issue-22897.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/issue-22897.rs:4:5
|
LL | [];
| ^^ cannot infer type for `[_; 0]`
| ^^ cannot infer type for array `[_; 0]`
error: aborting due to previous error

2
src/test/ui/type/type-check/issue-40294.stderr
View File

@ -11,7 +11,7 @@ LL | | {
LL | | x.foo();
LL | | y.foo();
LL | | }
| |_^ cannot infer type for `&'a T`
| |_^ cannot infer type for reference `&'a T`
|
= note: cannot resolve `&'a T: Foo`

2
src/test/ui/unconstrained-none.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/unconstrained-none.rs:4:5
|
LL | None;
| ^^^^ cannot infer type for `T`
| ^^^^ cannot infer type for type parameter `T`
error: aborting due to previous error

2
src/test/ui/unconstrained-ref.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/unconstrained-ref.rs:6:5
|
LL | S { o: &None };
| ^ cannot infer type for `T`
| ^ cannot infer type for type parameter `T`
error: aborting due to previous error

2
src/test/ui/vector-no-ann.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed for `std::vec::Vec<T>`
--> $DIR/vector-no-ann.rs:2:16
|
LL | let _foo = Vec::new();
| ---- ^^^^^^^^ cannot infer type for `T`
| ---- ^^^^^^^^ cannot infer type for type parameter `T`
| |
| consider giving `_foo` the explicit type `std::vec::Vec<T>`, where the type parameter `T` is specified