stage2: fix returning structs byval from functions

src/AstGen.zig

@@ -6473,7 +6473,7 @@ fn ret(gz: *GenZir, scope: *Scope, node: Ast.Node.Index) InnerError!Zir.Inst.Ref
         .never => {
             // Returning a value that cannot be an error; skip error defers.
             try genDefers(gz, defer_outer, scope, .normal_only);
-            _ = try gz.addUnNode(.ret_node, operand, node);
+            try gz.addRet(rl, operand, node);
             return Zir.Inst.Ref.unreachable_value;
         },
         .always => {

test/behavior/struct.zig

@@ -129,3 +129,18 @@ const MemberFnRand = struct {
         return r.seed;
     }
 };
+
+test "return struct byval from function" {
+    const bar = makeBar2(1234, 5678);
+    try expect(bar.y == 5678);
+}
+const Bar = struct {
+    x: i32,
+    y: i32,
+};
+fn makeBar2(x: i32, y: i32) Bar {
+    return Bar{
+        .x = x,
+        .y = y,
+    };
+}

test/behavior/struct_stage1.zig

@@ -61,21 +61,6 @@ test "store member function in variable" {
     try expect(result == 1234);
 }
 
-test "return struct byval from function" {
-    const bar = makeBar2(1234, 5678);
-    try expect(bar.y == 5678);
-}
-const Bar = struct {
-    x: i32,
-    y: i32,
-};
-fn makeBar2(x: i32, y: i32) Bar {
-    return Bar{
-        .x = x,
-        .y = y,
-    };
-}
-
 test "empty struct method call" {
     const es = EmptyStruct{};
     try expect(es.method() == 1234);