diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index e42d716d5ae0..3dd3cc537e6f 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -339,7 +339,7 @@ impl<'a> AstValidator<'a> {
         match &*fn_decl.inputs {
             [Param { ty, span, .. }] => {
                 if let TyKind::CVarArgs = ty.kind {
-                    self.session.emit_err(CVarArgsWithoutNamedArg { span: *span });
+                    self.session.emit_err(CVarArgsIsSoleParam { span: *span });
                 }
             }
             [ps @ .., _] => {
diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs
index 2b6d3d2a39a2..d376f638bd2e 100644
--- a/compiler/rustc_ast_passes/src/errors.rs
+++ b/compiler/rustc_ast_passes/src/errors.rs
@@ -114,8 +114,8 @@ pub struct TooManyParams {
 }
 
 #[derive(SessionDiagnostic)]
-#[error(ast_passes::c_var_args_without_named_arg)]
-pub struct CVarArgsWithoutNamedArg {
+#[error(ast_passes::c_var_args_is_sole_param)]
+pub struct CVarArgsIsSoleParam {
     #[primary_span]
     pub span: Span,
 }
diff --git a/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl b/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
index bca73baea004..49ef0cc83de3 100644
--- a/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
@@ -41,7 +41,7 @@ ast_passes_forbidden_non_lifetime_param =
 ast_passes_too_many_params =
     function can not have more than {$max_num_args} arguments
 
-ast_passes_c_var_args_without_named_arg =
+ast_passes_c_var_args_is_sole_param =
     C-variadic function must be declared with at least one named argument
 
 ast_passes_c_var_args_not_last =