bjoernager/rust
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Improve diagnostic for E0178 (bad + in type)

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Namely, use a more sensical primary span.
Don't pretty-print AST nodes for the diagnostic message. Why:
* It's lossy (e.g., it doesn't replicate trailing `+`s in trait objects.
* It's prone to leak error nodes (printed as `(/*ERROR*/)`) since
  the LHS can easily represent recovered code (e.g., `fn(i32?) + T`).
This commit is contained in:
León Orell Valerian Liehr 2025-04-15 07:44:24 +02:00
parent 8887af72a0
commit 6242335fdb
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GPG key ID: D17A07215F68E713
14 changed files with 51 additions and 52 deletions
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1
compiler/rustc_parse/src/errors.rs
View file

@ -30,7 +30,6 @@ pub(crate) struct AmbiguousPlus {
#[derive(Diagnostic)]
#[diag(parse_maybe_recover_from_bad_type_plus, code = E0178)]
pub(crate) struct BadTypePlus {
pub ty: String,
#[primary_span]
pub span: Span,
#[subdiagnostic]

10
compiler/rustc_parse/src/parser/diagnostics.rs
View file

@ -1636,19 +1636,19 @@ impl<'a> Parser<'a> {
self.bump(); // `+`
let _bounds = self.parse_generic_bounds()?;
let sum_span = ty.span.to(self.prev_token.span);
let sub = match &ty.kind {
TyKind::Ref(_lifetime, mut_ty) => {
let lo = mut_ty.ty.span.shrink_to_lo();
let hi = self.prev_token.span.shrink_to_hi();
BadTypePlusSub::AddParen { suggestion: AddParen { lo, hi } }
}
TyKind::Ptr(..) | TyKind::BareFn(..) => BadTypePlusSub::ForgotParen { span: sum_span },
_ => BadTypePlusSub::ExpectPath { span: sum_span },
TyKind::Ptr(..) | TyKind::BareFn(..) => {
BadTypePlusSub::ForgotParen { span: ty.span.to(self.prev_token.span) }
}
_ => BadTypePlusSub::ExpectPath { span: ty.span },
};
self.dcx().emit_err(BadTypePlus { ty: pprust::ty_to_string(ty), span: sum_span, sub });
self.dcx().emit_err(BadTypePlus { span: ty.span, sub });
Ok(())
}