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Rollup merge of #82774 - JohnTitor:bad-diag-for-anon-params-with-ref, r=estebank 

Fix bad diagnostics for anon params with ref and/or qualified paths

Fixes #82729
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This commit is contained in:
Yuki Okushi 2021-03-17 15:20:48 +09:00 committed by GitHub
parent e655fb6221 55bdf7f188
commit a16db3dcda
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 172 additions and 36 deletions
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104
compiler/rustc_parse/src/parser/diagnostics.rs
View File

@ -640,7 +640,7 @@ impl<'a> Parser<'a> {
}
}
Err(mut err) => {
// We could't parse generic parameters, unlikely to be a turbofish. Rely on
// We couldn't parse generic parameters, unlikely to be a turbofish. Rely on
// generic parse error instead.
err.cancel();
*self = snapshot;
@ -1242,7 +1242,7 @@ impl<'a> Parser<'a> {
let is_question = self.eat(&token::Question); // Handle `await? <expr>`.
let expr = if self.token == token::OpenDelim(token::Brace) {
// Handle `await { <expr> }`.
// This needs to be handled separatedly from the next arm to avoid
// This needs to be handled separately from the next arm to avoid
// interpreting `await { <expr> }?` as `<expr>?.await`.
self.parse_block_expr(None, self.token.span, BlockCheckMode::Default, AttrVec::new())
} else {
@ -1613,42 +1613,82 @@ impl<'a> Parser<'a> {
Applicability::HasPlaceholders,
);
return Some(ident);
} else if let PatKind::Ident(_, ident, _) = pat.kind {
if require_name
&& (self.token == token::Comma
|| self.token == token::Lt
|| self.token == token::CloseDelim(token::Paren))
{
// `fn foo(a, b) {}`, `fn foo(a<x>, b<y>) {}` or `fn foo(usize, usize) {}`
if first_param {
err.span_suggestion(
pat.span,
"if this is a `self` type, give it a parameter name",
format!("self: {}", ident),
Applicability::MaybeIncorrect,
);
} else if require_name
&& (self.token == token::Comma
|| self.token == token::Lt
|| self.token == token::CloseDelim(token::Paren))
{
let rfc_note = "anonymous parameters are removed in the 2018 edition (see RFC 1685)";
let (ident, self_sugg, param_sugg, type_sugg) = match pat.kind {
PatKind::Ident(_, ident, _) => (
ident,
format!("self: {}", ident),
format!("{}: TypeName", ident),
format!("_: {}", ident),
),
// Also catches `fn foo(&a)`.
PatKind::Ref(ref pat, mutab)
if matches!(pat.clone().into_inner().kind, PatKind::Ident(..)) =>
{
match pat.clone().into_inner().kind {
PatKind::Ident(_, ident, _) => {
let mutab = mutab.prefix_str();
(
ident,
format!("self: &{}{}", mutab, ident),
format!("{}: &{}TypeName", ident, mutab),
format!("_: &{}{}", mutab, ident),
)
}
_ => unreachable!(),
}
}
// Avoid suggesting that `fn foo(HashMap<u32>)` is fixed with a change to
// `fn foo(HashMap: TypeName<u32>)`.
if self.token != token::Lt {
err.span_suggestion(
pat.span,
"if this is a parameter name, give it a type",
format!("{}: TypeName", ident),
Applicability::HasPlaceholders,
);
_ => {
// Otherwise, try to get a type and emit a suggestion.
if let Some(ty) = pat.to_ty() {
err.span_suggestion_verbose(
pat.span,
"explicitly ignore the parameter name",
format!("_: {}", pprust::ty_to_string(&ty)),
Applicability::MachineApplicable,
);
err.note(rfc_note);
}
return None;
}
};
// `fn foo(a, b) {}`, `fn foo(a<x>, b<y>) {}` or `fn foo(usize, usize) {}`
if first_param {
err.span_suggestion(
pat.span,
"if this is a type, explicitly ignore the parameter name",
format!("_: {}", ident),
Applicability::MachineApplicable,
"if this is a `self` type, give it a parameter name",
self_sugg,
Applicability::MaybeIncorrect,
);
err.note("anonymous parameters are removed in the 2018 edition (see RFC 1685)");
// Don't attempt to recover by using the `X` in `X<Y>` as the parameter name.
return if self.token == token::Lt { None } else { Some(ident) };
}
// Avoid suggesting that `fn foo(HashMap<u32>)` is fixed with a change to
// `fn foo(HashMap: TypeName<u32>)`.
if self.token != token::Lt {
err.span_suggestion(
pat.span,
"if this is a parameter name, give it a type",
param_sugg,
Applicability::HasPlaceholders,
);
}
err.span_suggestion(
pat.span,
"if this is a type, explicitly ignore the parameter name",
type_sugg,
Applicability::MachineApplicable,
);
err.note(rfc_note);
// Don't attempt to recover by using the `X` in `X<Y>` as the parameter name.
return if self.token == token::Lt { None } else { Some(ident) };
}
None
}

14
src/test/ui/anon-params/anon-params-denied-2018.rs
View File

@ -5,6 +5,20 @@
trait T {
fn foo(i32); //~ expected one of `:`, `@`, or `|`, found `)`
// Also checks with `&`
fn foo_with_ref(&mut i32);
//~^ ERROR expected one of `:`, `@`, or `|`, found `)`
fn foo_with_qualified_path(<Bar as T>::Baz);
//~^ ERROR expected one of `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)`
fn foo_with_qualified_path_and_ref(&<Bar as T>::Baz);
//~^ ERROR expected one of `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)`
fn foo_with_multiple_qualified_paths(<Bar as T>::Baz, <Bar as T>::Baz);
//~^ ERROR expected one of `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `,`
//~| ERROR expected one of `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)`
fn bar_with_default_impl(String, String) {}
//~^ ERROR expected one of `:`
//~| ERROR expected one of `:`

76
src/test/ui/anon-params/anon-params-denied-2018.stderr
View File

@ -18,8 +18,76 @@ help: if this is a type, explicitly ignore the parameter name
LL | fn foo(_: i32);
| ^^^^^^
error: expected one of `:`, `@`, or `|`, found `)`
--> $DIR/anon-params-denied-2018.rs:9:29
|
LL | fn foo_with_ref(&mut i32);
| ^ expected one of `:`, `@`, or `|`
|
= note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: if this is a `self` type, give it a parameter name
|
LL | fn foo_with_ref(self: &mut i32);
| ^^^^^^^^^^^^^^
help: if this is a parameter name, give it a type
|
LL | fn foo_with_ref(i32: &mut TypeName);
| ^^^^^^^^^^^^^^^^^^
help: if this is a type, explicitly ignore the parameter name
|
LL | fn foo_with_ref(_: &mut i32);
| ^^^^^^^^^^^
error: expected one of `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)`
--> $DIR/anon-params-denied-2018.rs:12:47
|
LL | fn foo_with_qualified_path(<Bar as T>::Baz);
| ^ expected one of 8 possible tokens
|
= note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: explicitly ignore the parameter name
|
LL | fn foo_with_qualified_path(_: <Bar as T>::Baz);
| ^^^^^^^^^^^^^^^^^^
error: expected one of `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)`
--> $DIR/anon-params-denied-2018.rs:15:56
|
LL | fn foo_with_qualified_path_and_ref(&<Bar as T>::Baz);
| ^ expected one of 8 possible tokens
|
= note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: explicitly ignore the parameter name
|
LL | fn foo_with_qualified_path_and_ref(_: &<Bar as T>::Baz);
| ^^^^^^^^^^^^^^^^^^^
error: expected one of `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `,`
--> $DIR/anon-params-denied-2018.rs:18:57
|
LL | fn foo_with_multiple_qualified_paths(<Bar as T>::Baz, <Bar as T>::Baz);
| ^ expected one of 8 possible tokens
|
= note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: explicitly ignore the parameter name
|
LL | fn foo_with_multiple_qualified_paths(_: <Bar as T>::Baz, <Bar as T>::Baz);
| ^^^^^^^^^^^^^^^^^^
error: expected one of `(`, `...`, `..=`, `..`, `::`, `:`, `{`, or `|`, found `)`
--> $DIR/anon-params-denied-2018.rs:18:74
|
LL | fn foo_with_multiple_qualified_paths(<Bar as T>::Baz, <Bar as T>::Baz);
| ^ expected one of 8 possible tokens
|
= note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: explicitly ignore the parameter name
|
LL | fn foo_with_multiple_qualified_paths(<Bar as T>::Baz, _: <Bar as T>::Baz);
| ^^^^^^^^^^^^^^^^^^
error: expected one of `:`, `@`, or `|`, found `,`
--> $DIR/anon-params-denied-2018.rs:8:36
--> $DIR/anon-params-denied-2018.rs:22:36
|
LL | fn bar_with_default_impl(String, String) {}
| ^ expected one of `:`, `@`, or `|`
@ -39,7 +107,7 @@ LL | fn bar_with_default_impl(_: String, String) {}
| ^^^^^^^^^
error: expected one of `:`, `@`, or `|`, found `)`
--> $DIR/anon-params-denied-2018.rs:8:44
--> $DIR/anon-params-denied-2018.rs:22:44
|
LL | fn bar_with_default_impl(String, String) {}
| ^ expected one of `:`, `@`, or `|`
@ -55,7 +123,7 @@ LL | fn bar_with_default_impl(String, _: String) {}
| ^^^^^^^^^
error: expected one of `:`, `@`, or `|`, found `,`
--> $DIR/anon-params-denied-2018.rs:13:22
--> $DIR/anon-params-denied-2018.rs:27:22
|
LL | fn baz(a:usize, b, c: usize) -> usize {
| ^ expected one of `:`, `@`, or `|`
@ -70,5 +138,5 @@ help: if this is a type, explicitly ignore the parameter name
LL | fn baz(a:usize, _: b, c: usize) -> usize {
| ^^^^
error: aborting due to 4 previous errors
error: aborting due to 9 previous errors

14
src/test/ui/parser/lifetime-in-pattern.stderr
View File

@ -9,6 +9,20 @@ error: expected one of `:`, `@`, or `|`, found `)`
|
LL | fn test(&'a str) {
| ^ expected one of `:`, `@`, or `|`
|
= note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
help: if this is a `self` type, give it a parameter name
|
LL | fn test(self: &str) {
| ^^^^^^^^^^
help: if this is a parameter name, give it a type
|
LL | fn test(str: &TypeName) {
| ^^^^^^^^^^^^^^
help: if this is a type, explicitly ignore the parameter name
|
LL | fn test(_: &str) {
| ^^^^^^^
error: aborting due to 2 previous errors