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Point at individual type arguments on arg count mismatch

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estebank committed Jun 1, 2019
1 parent 8e595f5 commit 28859472f71cea497dbea12523e69dc23daaff76
@@ -16,7 +16,7 @@ use crate::util::nodemap::{NodeMap, FxHashSet};
use crate::mir::mono::Linkage;

use errors::FatalError;
use syntax_pos::{Span, DUMMY_SP, symbol::InternedString};
use syntax_pos::{Span, DUMMY_SP, symbol::InternedString, MultiSpan};
use syntax::source_map::Spanned;
use rustc_target::spec::abi::Abi;
use syntax::ast::{self, CrateSugar, Ident, Name, NodeId, AsmDialect};
@@ -624,6 +624,14 @@ impl Generics {
}
None
}

pub fn spans(&self) -> MultiSpan {
if self.params.is_empty() {
self.span.into()
} else {
self.params.iter().map(|p| p.span).collect::<Vec<Span>>().into()
}
}
}

/// Synthetic type parameters are converted to another form during lowering; this allows
@@ -583,7 +583,7 @@ fn compare_self_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
fn compare_number_of_generics<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
impl_: &ty::AssocItem,
impl_span: Span,
_impl_span: Span,
trait_: &ty::AssocItem,
trait_span: Option<Span>,
) -> Result<(), ErrorReported> {
@@ -600,17 +600,25 @@ fn compare_number_of_generics<'a, 'tcx>(
if impl_count != trait_count {
err_occurred = true;

let impl_hir_id = tcx.hir().as_local_hir_id(impl_.def_id).unwrap();
let impl_item = tcx.hir().expect_impl_item(impl_hir_id);
let span = if impl_item.generics.params.is_empty()
|| impl_item.generics.span.is_dummy() { // argument position impl Trait (#55374)
impl_span
let trait_spans = if let Some(trait_hir_id) = tcx.hir().as_local_hir_id(trait_.def_id) {
let trait_item = tcx.hir().expect_trait_item(trait_hir_id);
Some(if trait_item.generics.params.is_empty() {
vec![trait_item.generics.span]
} else {
trait_item.generics.params.iter().map(|p| p.span).collect::<Vec<Span>>()
})
} else {
impl_item.generics.span
trait_span.map(|s| vec![s])
};

let impl_hir_id = tcx.hir().as_local_hir_id(impl_.def_id).unwrap();
let impl_item = tcx.hir().expect_impl_item(impl_hir_id);
// let span = impl_item.generics.span;
let spans = impl_item.generics.spans();
let span = spans.primary_span();

let mut err = tcx.sess.struct_span_err_with_code(
span,
spans,
&format!(
"method `{}` has {} {kind} parameter{} but its trait \
declaration has {} {kind} parameter{}",
@@ -626,22 +634,32 @@ fn compare_number_of_generics<'a, 'tcx>(

let mut suffix = None;

if let Some(span) = trait_span {
err.span_label(
span,
format!("expected {} {} parameter{}", trait_count, kind,
if trait_count != 1 { "s" } else { "" })
);
if let Some(spans) = trait_spans {
let mut spans = spans.iter();
if let Some(span) = spans.next() {
err.span_label(*span, format!(
"expected {} {} parameter{}",
trait_count,
kind,
if trait_count != 1 { "s" } else { "" },
));
}
for span in spans {
err.span_label(*span, "");
}
} else {
suffix = Some(format!(", expected {}", trait_count));
}

err.span_label(
span,
format!("found {} {} parameter{}{}", impl_count, kind,
if let Some(span) = span {
err.span_label(span, format!(
"found {} {} parameter{}{}",
impl_count,
kind,
if impl_count != 1 { "s" } else { "" },
suffix.unwrap_or_else(|| String::new())),
);
suffix.unwrap_or_else(|| String::new()),
));
}

err.emit();
}
@@ -8,5 +8,15 @@ impl Foo for Bar {
fn foo(x: bool) -> Self { Bar } //~ ERROR E0049
}

trait Fuzz {
fn fuzz<A: Default, B>(x: A, y: B) -> Self;
}

struct Baz;

impl Fuzz for Baz {
fn fuzz(x: bool, y: bool) -> Self { Baz } //~ ERROR E0049
}

fn main() {
}
@@ -1,12 +1,23 @@
error[E0049]: method `foo` has 0 type parameters but its trait declaration has 1 type parameter
--> $DIR/E0049.rs:8:5
--> $DIR/E0049.rs:8:11
|
LL | fn foo<T: Default>(x: T) -> Self;
| --------------------------------- expected 1 type parameter
| - expected 1 type parameter
...
LL | fn foo(x: bool) -> Self { Bar }
| ^^^^^^^^^^^^^^^^^^^^^^^ found 0 type parameters
| ^ found 0 type parameters

error: aborting due to previous error
error[E0049]: method `fuzz` has 0 type parameters but its trait declaration has 2 type parameters
--> $DIR/E0049.rs:18:12
|
LL | fn fuzz<A: Default, B>(x: A, y: B) -> Self;
| - -
| |
| expected 2 type parameters
...
LL | fn fuzz(x: bool, y: bool) -> Self { Baz }
| ^ found 0 type parameters

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0049`.
@@ -1,8 +1,8 @@
error[E0049]: method `foo` has 1 type parameter but its trait declaration has 0 type parameters
--> $DIR/issue-36708.rs:8:11
--> $DIR/issue-36708.rs:8:12
|
LL | fn foo<T>() {}
| ^^^ found 1 type parameter, expected 0
| ^ found 1 type parameter, expected 0

error: aborting due to previous error

@@ -1,11 +1,11 @@
error[E0049]: method `foo` has 1 type parameter but its trait declaration has 0 type parameters
--> $DIR/type-arg-mismatch-due-to-impl-trait.rs:10:11
--> $DIR/type-arg-mismatch-due-to-impl-trait.rs:10:22
|
LL | fn foo(&self, t: Self::T);
| -------------------------- expected 0 type parameters
| - expected 0 type parameters
...
LL | fn foo(&self, t: impl Clone) {}
| ^ found 1 type parameter
| ^^^^^^^^^^ found 1 type parameter

error: aborting due to previous error

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