bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Explicitly reject const C-variadic functions

Browse source 
Trying to use C-variadics in a const function would previously fail with
an error like "destructor of `VaListImpl<'_>` cannot be evaluated at
compile-time".

Add an explicit check for const C-variadics to provide a clearer error:
"functions cannot be both `const` and C-variadic".
This commit is contained in:
Nicholas Bishop 2023-10-29 17:28:56 -04:00
parent 8508e65895
commit f91b5ceaf2
5 changed files with 120 additions and 22 deletions
Download patch file Download diff file Expand all files Collapse all files

19
compiler/rustc_ast_passes/src/ast_validation.rs
View file

@ -482,8 +482,11 @@ impl<'a> AstValidator<'a> {
}
}
/// Reject C-variadic type unless the function is foreign,
/// or free and `unsafe extern "C"` semantically.
/// Reject invalid C-variadic types.
///
/// C-variadics must be:
/// - Non-const
/// - Either foreign, or free and `unsafe extern "C"` semantically
fn check_c_variadic_type(&self, fk: FnKind<'a>) {
let variadic_spans: Vec<_> = fk
.decl()
@ -497,6 +500,18 @@ impl<'a> AstValidator<'a> {
return;
}
if let Some(header) = fk.header() {
if let Const::Yes(const_span) = header.constness {
let mut spans = variadic_spans.clone();
spans.push(const_span);
self.err_handler().emit_err(errors::ConstAndCVariadic {
spans,
const_span,
variadic_spans: variadic_spans.clone(),
});
}
}
match (fk.ctxt(), fk.header()) {
(Some(FnCtxt::Foreign), _) => return,
(Some(FnCtxt::Free), Some(header)) => match header.ext {