bjoernager/rust
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Reject const in inherent impls

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This commit is contained in:
Dylan MacKenzie 2020-01-03 16:32:01 -08:00
parent b390fc4cf1
commit 31edbe9aca
1 changed files with 12 additions and 3 deletions
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15
src/librustc_parse/parser/item.rs
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@ -5,7 +5,7 @@ use crate::maybe_whole;
use rustc_error_codes::*;
use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, PResult, StashKey};
use rustc_span::source_map::{self, respan, Span};
use rustc_span::source_map::{self, respan, Span, Spanned};
use rustc_span::symbol::{kw, sym, Symbol};
use rustc_span::BytePos;
use syntax::ast::{self, AttrKind, AttrStyle, AttrVec, Attribute, Ident, DUMMY_NODE_ID};
@ -560,8 +560,9 @@ impl<'a> Parser<'a> {
};
let constness = if self.eat_keyword(kw::Const) {
self.sess.gated_spans.gate(sym::const_trait_impl, self.prev_span);
Some(Constness::Const)
let span = self.prev_span;
self.sess.gated_spans.gate(sym::const_trait_impl, span);
Some(respan(span, Constness::Const))
} else {
None
};
@ -626,6 +627,7 @@ impl<'a> Parser<'a> {
err_path(ty_first.span)
}
};
let constness = constness.map(|c| c.node);
let trait_ref = TraitRef { path, constness, ref_id: ty_first.id };
ItemKind::Impl(
@ -639,6 +641,13 @@ impl<'a> Parser<'a> {
)
}
None => {
// Reject `impl const Type {}` here
if let Some(Spanned { node: Constness::Const, span }) = constness {
self.struct_span_err(span, "`const` cannot modify an inherent impl")
.help("only a trait impl can be `const`")
.emit();
}
// impl Type
ItemKind::Impl(
unsafety,