Recover upon encountering mistyped Const in const param def

This commit is contained in:
许杰友 Jieyou Xu (Joe) 2023-05-28 01:18:51 +00:00
parent b9c5fdc888
commit 41f5a30690
No known key found for this signature in database
GPG Key ID: C5FD5D32014FDB47
3 changed files with 106 additions and 0 deletions

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@ -43,6 +43,15 @@ impl<'a> Parser<'a> {
fn parse_ty_param(&mut self, preceding_attrs: AttrVec) -> PResult<'a, GenericParam> {
let ident = self.parse_ident()?;
// We might have a typo'd `Const` that was parsed as a type parameter.
if self.may_recover()
&& ident.name.as_str().to_ascii_lowercase() == kw::Const.as_str()
&& self.check_ident()
// `Const` followed by IDENT
{
return Ok(self.recover_const_param_with_mistyped_const(preceding_attrs, ident)?);
}
// Parse optional colon and param bounds.
let mut colon_span = None;
let bounds = if self.eat(&token::Colon) {
@ -120,6 +129,41 @@ impl<'a> Parser<'a> {
})
}
pub(crate) fn recover_const_param_with_mistyped_const(
&mut self,
preceding_attrs: AttrVec,
mistyped_const_ident: Ident,
) -> PResult<'a, GenericParam> {
let ident = self.parse_ident()?;
self.expect(&token::Colon)?;
let ty = self.parse_ty()?;
// Parse optional const generics default value.
let default = if self.eat(&token::Eq) { Some(self.parse_const_arg()?) } else { None };
let mut err = self.struct_span_err(
mistyped_const_ident.span,
format!("`const` keyword was mistyped as `{}`", mistyped_const_ident.as_str()),
);
err.span_suggestion_verbose(
mistyped_const_ident.span,
"use the `const` keyword",
kw::Const.as_str(),
Applicability::MachineApplicable,
);
err.emit();
Ok(GenericParam {
ident,
id: ast::DUMMY_NODE_ID,
attrs: preceding_attrs,
bounds: Vec::new(),
kind: GenericParamKind::Const { ty, kw_span: mistyped_const_ident.span, default },
is_placeholder: false,
colon_span: None,
})
}
/// Parses a (possibly empty) list of lifetime and type parameters, possibly including
/// a trailing comma and erroneous trailing attributes.
pub(super) fn parse_generic_params(&mut self) -> PResult<'a, ThinVec<ast::GenericParam>> {

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@ -0,0 +1,16 @@
pub fn foo<Const N: u8>() {}
//~^ ERROR `const` keyword was mistyped as `Const`
pub fn bar<Const>() {}
// OK
pub fn baz<Const N: u8, T>() {}
//~^ ERROR `const` keyword was mistyped as `Const`
pub fn qux<T, Const N: u8>() {}
//~^ ERROR `const` keyword was mistyped as `Const`
pub fn quux<T, Const N: u8, U>() {}
//~^ ERROR `const` keyword was mistyped as `Const`
fn main() {}

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@ -0,0 +1,46 @@
error: `const` keyword was mistyped as `Const`
--> $DIR/typod-const-in-const-param-def.rs:1:12
|
LL | pub fn foo<Const N: u8>() {}
| ^^^^^
|
help: use the `const` keyword
|
LL | pub fn foo<const N: u8>() {}
| ~~~~~
error: `const` keyword was mistyped as `Const`
--> $DIR/typod-const-in-const-param-def.rs:7:12
|
LL | pub fn baz<Const N: u8, T>() {}
| ^^^^^
|
help: use the `const` keyword
|
LL | pub fn baz<const N: u8, T>() {}
| ~~~~~
error: `const` keyword was mistyped as `Const`
--> $DIR/typod-const-in-const-param-def.rs:10:15
|
LL | pub fn qux<T, Const N: u8>() {}
| ^^^^^
|
help: use the `const` keyword
|
LL | pub fn qux<T, const N: u8>() {}
| ~~~~~
error: `const` keyword was mistyped as `Const`
--> $DIR/typod-const-in-const-param-def.rs:13:16
|
LL | pub fn quux<T, Const N: u8, U>() {}
| ^^^^^
|
help: use the `const` keyword
|
LL | pub fn quux<T, const N: u8, U>() {}
| ~~~~~
error: aborting due to 4 previous errors