Don't accidentally promote union access in MIR

rust-lang · Aug 7, 2018 · 07e2dd7 · 07e2dd7
1 parent c0aedc0
commit 07e2dd7
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Showing 2 changed files with 1 addition and 12 deletions.
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
@@ -515,7 +515,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                             if let Some(def) = base_ty.ty_adt_def() {
                                 if def.is_union() {
                                     match this.mode {
-                                        Mode::Fn => {},
+                                        Mode::Fn => this.not_const(),
                                         Mode::ConstFn => {
                                             if !this.tcx.sess.features_untracked().const_fn_union {
                                                 emit_feature_err(

diff --git a/src/test/ui/const-eval/union_promotion.nll.stderr b/src/test/ui/const-eval/union_promotion.nll.stderr