diff --git a/compiler/rustc_ast_passes/messages.ftl b/compiler/rustc_ast_passes/messages.ftl
index 43020a93078..d22bae816ef 100644
--- a/compiler/rustc_ast_passes/messages.ftl
+++ b/compiler/rustc_ast_passes/messages.ftl
@@ -42,6 +42,10 @@ ast_passes_const_and_async = functions cannot be both `const` and `async`
.async = `async` because of this
.label = {""}
+ast_passes_const_and_c_variadic = functions cannot be both `const` and C-variadic
+ .const = `const` because of this
+ .variadic = C-variadic because of this
+
ast_passes_const_without_body =
free constant item without body
.suggestion = provide a definition for the constant
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index f59f7d389cd..477d3732d46 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -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 {
diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs
index 579f528e20f..d14b62d6bdc 100644
--- a/compiler/rustc_ast_passes/src/errors.rs
+++ b/compiler/rustc_ast_passes/src/errors.rs
@@ -583,6 +583,17 @@ pub struct ConstAndAsync {
pub span: Span,
}
+#[derive(Diagnostic)]
+#[diag(ast_passes_const_and_c_variadic)]
+pub struct ConstAndCVariadic {
+ #[primary_span]
+ pub spans: Vec<Span>,
+ #[label(ast_passes_const)]
+ pub const_span: Span,
+ #[label(ast_passes_variadic)]
+ pub variadic_spans: Vec<Span>,
+}
+
#[derive(Diagnostic)]
#[diag(ast_passes_pattern_in_foreign, code = "E0130")]
pub struct PatternInForeign {
diff --git a/tests/ui/parser/variadic-ffi-semantic-restrictions.rs b/tests/ui/parser/variadic-ffi-semantic-restrictions.rs
index 8e382314ca2..b173e23e7a1 100644
--- a/tests/ui/parser/variadic-ffi-semantic-restrictions.rs
+++ b/tests/ui/parser/variadic-ffi-semantic-restrictions.rs
@@ -32,6 +32,18 @@ extern "C" fn f3_3(..., x: isize) {}
//~^ ERROR only foreign or `unsafe extern "C"` functions may be C-variadic
//~| ERROR `...` must be the last argument of a C-variadic function
+const unsafe extern "C" fn f4_1(x: isize, ...) {}
+//~^ ERROR functions cannot be both `const` and C-variadic
+
+const extern "C" fn f4_2(x: isize, ...) {}
+//~^ ERROR functions cannot be both `const` and C-variadic
+//~| ERROR only foreign or `unsafe extern "C"` functions may be C-variadic
+
+const extern "C" fn f4_3(..., x: isize, ...) {}
+//~^ ERROR functions cannot be both `const` and C-variadic
+//~| ERROR only foreign or `unsafe extern "C"` functions may be C-variadic
+//~| ERROR `...` must be the last argument of a C-variadic function
+
extern "C" {
fn e_f1(...);
//~^ ERROR C-variadic function must be declared with at least one named argument
@@ -53,6 +65,9 @@ impl X {
fn i_f4(..., x: isize, ...) {}
//~^ ERROR only foreign or `unsafe extern "C"` functions may be C-variadic
//~| ERROR `...` must be the last argument of a C-variadic function
+ const fn i_f5(x: isize, ...) {}
+ //~^ ERROR only foreign or `unsafe extern "C"` functions may be C-variadic
+ //~| ERROR functions cannot be both `const` and C-variadic
}
trait T {
diff --git a/tests/ui/parser/variadic-ffi-semantic-restrictions.stderr b/tests/ui/parser/variadic-ffi-semantic-restrictions.stderr
index 95e381f06fc..18526080e4c 100644
--- a/tests/ui/parser/variadic-ffi-semantic-restrictions.stderr
+++ b/tests/ui/parser/variadic-ffi-semantic-restrictions.stderr
@@ -76,119 +76,172 @@ error: only foreign or `unsafe extern "C"` functions may be C-variadic
LL | extern "C" fn f3_3(..., x: isize) {}
| ^^^
+error: functions cannot be both `const` and C-variadic
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:35:1
+ |
+LL | const unsafe extern "C" fn f4_1(x: isize, ...) {}
+ | ^^^^^ `const` because of this ^^^ C-variadic because of this
+
+error: functions cannot be both `const` and C-variadic
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:38:1
+ |
+LL | const extern "C" fn f4_2(x: isize, ...) {}
+ | ^^^^^ `const` because of this ^^^ C-variadic because of this
+
+error: only foreign or `unsafe extern "C"` functions may be C-variadic
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:38:36
+ |
+LL | const extern "C" fn f4_2(x: isize, ...) {}
+ | ^^^
+
+error: `...` must be the last argument of a C-variadic function
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:42:26
+ |
+LL | const extern "C" fn f4_3(..., x: isize, ...) {}
+ | ^^^
+
+error: functions cannot be both `const` and C-variadic
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:42:1
+ |
+LL | const extern "C" fn f4_3(..., x: isize, ...) {}
+ | ^^^^^ ^^^ ^^^ C-variadic because of this
+ | | |
+ | | C-variadic because of this
+ | `const` because of this
+
+error: only foreign or `unsafe extern "C"` functions may be C-variadic
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:42:26
+ |
+LL | const extern "C" fn f4_3(..., x: isize, ...) {}
+ | ^^^ ^^^
+
error: C-variadic function must be declared with at least one named argument
- --> $DIR/variadic-ffi-semantic-restrictions.rs:36:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:48:13
|
LL | fn e_f1(...);
| ^^^
error: `...` must be the last argument of a C-variadic function
- --> $DIR/variadic-ffi-semantic-restrictions.rs:38:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:50:13
|
LL | fn e_f2(..., x: isize);
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:45:23
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:57:23
|
LL | fn i_f1(x: isize, ...) {}
| ^^^
error: C-variadic function must be declared with at least one named argument
- --> $DIR/variadic-ffi-semantic-restrictions.rs:47:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:59:13
|
LL | fn i_f2(...) {}
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:47:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:59:13
|
LL | fn i_f2(...) {}
| ^^^
error: `...` must be the last argument of a C-variadic function
- --> $DIR/variadic-ffi-semantic-restrictions.rs:50:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:62:13
|
LL | fn i_f3(..., x: isize, ...) {}
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:50:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:62:13
|
LL | fn i_f3(..., x: isize, ...) {}
| ^^^ ^^^
error: `...` must be the last argument of a C-variadic function
- --> $DIR/variadic-ffi-semantic-restrictions.rs:53:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:65:13
|
LL | fn i_f4(..., x: isize, ...) {}
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:53:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:65:13
|
LL | fn i_f4(..., x: isize, ...) {}
| ^^^ ^^^
+error: functions cannot be both `const` and C-variadic
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:68:5
+ |
+LL | const fn i_f5(x: isize, ...) {}
+ | ^^^^^ ^^^ C-variadic because of this
+ | |
+ | `const` because of this
+
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:59:23
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:68:29
+ |
+LL | const fn i_f5(x: isize, ...) {}
+ | ^^^
+
+error: only foreign or `unsafe extern "C"` functions may be C-variadic
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:74:23
|
LL | fn t_f1(x: isize, ...) {}
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:61:23
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:76:23
|
LL | fn t_f2(x: isize, ...);
| ^^^
error: C-variadic function must be declared with at least one named argument
- --> $DIR/variadic-ffi-semantic-restrictions.rs:63:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:78:13
|
LL | fn t_f3(...) {}
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:63:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:78:13
|
LL | fn t_f3(...) {}
| ^^^
error: C-variadic function must be declared with at least one named argument
- --> $DIR/variadic-ffi-semantic-restrictions.rs:66:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:81:13
|
LL | fn t_f4(...);
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:66:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:81:13
|
LL | fn t_f4(...);
| ^^^
error: `...` must be the last argument of a C-variadic function
- --> $DIR/variadic-ffi-semantic-restrictions.rs:69:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:84:13
|
LL | fn t_f5(..., x: isize) {}
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:69:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:84:13
|
LL | fn t_f5(..., x: isize) {}
| ^^^
error: `...` must be the last argument of a C-variadic function
- --> $DIR/variadic-ffi-semantic-restrictions.rs:72:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:87:13
|
LL | fn t_f6(..., x: isize);
| ^^^
error: only foreign or `unsafe extern "C"` functions may be C-variadic
- --> $DIR/variadic-ffi-semantic-restrictions.rs:72:13
+ --> $DIR/variadic-ffi-semantic-restrictions.rs:87:13
|
LL | fn t_f6(..., x: isize);
| ^^^
-error: aborting due to 32 previous errors
+error: aborting due to 40 previous errors