Commit 587ef60a28

@@ -7580,7 +7580,8 @@ fn zirEnumToInt(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!A
     const enum_tag: Air.Inst.Ref = switch (operand_ty.zigTypeTag()) {
         .Enum => operand,
         .Union => blk: {
-            const tag_ty = operand_ty.unionTagType() orelse {
+            const union_ty = try sema.resolveTypeFields(operand_ty);
+            const tag_ty = union_ty.unionTagType() orelse {
                 return sema.fail(
                     block,
                     operand_src,
@@ -22713,7 +22714,8 @@ fn fieldPtr(
                             return inst;
                         }
                     }
-                    if (child_type.unionTagType()) |enum_ty| {
+                    const union_ty = try sema.resolveTypeFields(child_type);
+                    if (union_ty.unionTagType()) |enum_ty| {
                         if (enum_ty.enumFieldIndex(field_name)) |field_index| {
                             const field_index_u32 = @intCast(u32, field_index);
                             var anon_decl = try block.startAnonDecl();

@@ -0,0 +1,16 @@
+const T = union(enum) {
+    a,
+    pub fn f(self: T) void {
+        _ = self;
+    }
+};
+pub export fn entry() void {
+    T.a.f();
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :8:8: error: no field or member function named 'f' in '@typeInfo(tmp.T).Union.tag_type.?'
+// :1:11: note: enum declared here