From 963fdbc8521839baf833e007e8135794fd1d49d2 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Fri, 13 Jun 2025 17:18:26 +0200
Subject: variadic functions: remove list of supported ABIs from error

---
 compiler/rustc_hir_analysis/messages.ftl  |  2 +-
 compiler/rustc_hir_analysis/src/errors.rs |  2 +-
 compiler/rustc_hir_analysis/src/lib.rs    | 18 +++++-------------
 3 files changed, 7 insertions(+), 15 deletions(-)

(limited to 'compiler')

diff --git a/compiler/rustc_hir_analysis/messages.ftl b/compiler/rustc_hir_analysis/messages.ftl
index 4fcd9f8a646..7c14a055763 100644
--- a/compiler/rustc_hir_analysis/messages.ftl
+++ b/compiler/rustc_hir_analysis/messages.ftl
@@ -595,7 +595,7 @@ hir_analysis_value_of_associated_struct_already_specified =
     .label = re-bound here
     .previous_bound_label = `{$item_name}` bound here first
 
-hir_analysis_variadic_function_compatible_convention = C-variadic function must have a compatible calling convention, like {$conventions}
+hir_analysis_variadic_function_compatible_convention = C-variadic functions with the {$convention} calling convention are not supported
     .label = C-variadic function must have a compatible calling convention
 
 hir_analysis_variances_of = {$variances}
diff --git a/compiler/rustc_hir_analysis/src/errors.rs b/compiler/rustc_hir_analysis/src/errors.rs
index a27d1ed6c53..c47c9cb2848 100644
--- a/compiler/rustc_hir_analysis/src/errors.rs
+++ b/compiler/rustc_hir_analysis/src/errors.rs
@@ -633,7 +633,7 @@ pub(crate) struct VariadicFunctionCompatibleConvention<'a> {
     #[primary_span]
     #[label]
     pub span: Span,
-    pub conventions: &'a str,
+    pub convention: &'a str,
 }
 
 #[derive(Diagnostic)]
diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index 007f3a6abf6..4f699462ac3 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -115,12 +115,6 @@ fn require_c_abi_if_c_variadic(
     abi: ExternAbi,
     span: Span,
 ) {
-    const CONVENTIONS_UNSTABLE: &str =
-        "`C`, `cdecl`, `system`, `aapcs`, `win64`, `sysv64` or `efiapi`";
-    const CONVENTIONS_STABLE: &str = "`C` or `cdecl`";
-    const UNSTABLE_EXPLAIN: &str =
-        "using calling conventions other than `C` or `cdecl` for varargs functions is unstable";
-
     // ABIs which can stably use varargs
     if !decl.c_variadic || matches!(abi, ExternAbi::C { .. } | ExternAbi::Cdecl { .. }) {
         return;
@@ -140,20 +134,18 @@ fn require_c_abi_if_c_variadic(
 
     // Looks like we need to pick an error to emit.
     // Is there any feature which we could have enabled to make this work?
+    let unstable_explain =
+        format!("C-variadic functions with the {abi} calling convention are unstable");
     match abi {
         ExternAbi::System { .. } => {
-            feature_err(&tcx.sess, sym::extern_system_varargs, span, UNSTABLE_EXPLAIN)
+            feature_err(&tcx.sess, sym::extern_system_varargs, span, unstable_explain)
         }
         abi if abi.supports_varargs() => {
-            feature_err(&tcx.sess, sym::extended_varargs_abi_support, span, UNSTABLE_EXPLAIN)
+            feature_err(&tcx.sess, sym::extended_varargs_abi_support, span, unstable_explain)
         }
         _ => tcx.dcx().create_err(errors::VariadicFunctionCompatibleConvention {
             span,
-            conventions: if tcx.sess.opts.unstable_features.is_nightly_build() {
-                CONVENTIONS_UNSTABLE
-            } else {
-                CONVENTIONS_STABLE
-            },
+            convention: &format!("{abi}"),
         }),
     }
     .emit();
-- 
cgit 1.4.1-3-g733a5