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Fix bad diagnostics for anon params with ref
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@JohnTitor
JohnTitor committed Mar 16, 2021
1 parent f5d8117 commit ea355bc
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Showing 4 changed files with 96 additions and 35 deletions.
85 changes: 54 additions & 31 deletions compiler/rustc_parse/src/parser/diagnostics.rs
View file
Expand Up @@ -1613,42 +1613,65 @@ 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,
);
}
// 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,
);
} else if require_name
&& (self.token == token::Comma
|| self.token == token::Lt
|| self.token == token::CloseDelim(token::Paren))
{
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 let PatKind::Ident(_, ident, _) = pat.clone().into_inner().kind {
let mutab = mutab.prefix_str();
(
ident,
format!("self: &{}{}", mutab, ident),
format!("{}: &{}TypeName", ident, mutab),
format!("_: &{}{}", mutab, ident),
)
} else {
return None;
}
}
// Ignore other `PatKind`.
_ => 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,
);
}
// 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.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) };
}
err.span_suggestion(
pat.span,
"if this is a type, explicitly ignore the parameter name",
type_sugg,
Applicability::MachineApplicable,
);
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) };
}
None
}
Expand Down
4 changes: 4 additions & 0 deletions src/test/ui/anon-params/anon-params-denied-2018.rs
View file
Expand Up @@ -5,6 +5,10 @@
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 bar_with_default_impl(String, String) {}
//~^ ERROR expected one of `:`
//~| ERROR expected one of `:`
Expand Down
28 changes: 24 additions & 4 deletions src/test/ui/anon-params/anon-params-denied-2018.stderr
View file
Expand Up @@ -18,8 +18,28 @@ 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:8:36
--> $DIR/anon-params-denied-2018.rs:12:36
|
LL | fn bar_with_default_impl(String, String) {}
| ^ expected one of `:`, `@`, or `|`
Expand All @@ -39,7 +59,7 @@ 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:12:44
|
LL | fn bar_with_default_impl(String, String) {}
| ^ expected one of `:`, `@`, or `|`
Expand All @@ -55,7 +75,7 @@ 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:17:22
|
LL | fn baz(a:usize, b, c: usize) -> usize {
| ^ expected one of `:`, `@`, or `|`
Expand All @@ -70,5 +90,5 @@ 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 5 previous errors

14 changes: 14 additions & 0 deletions src/test/ui/parser/lifetime-in-pattern.stderr
View file
Expand Up @@ -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

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