Sema: validate equality on store to comptime field

2 files changed, 42 insertions, 0 deletions

diff --git a/test/behavior/struct.zig b/test/behavior/struct.zig
index 5cbb8e973e..624f1609d4 100644
--- a/test/behavior/struct.zig
+++ b/test/behavior/struct.zig
@@ -1336,3 +1336,25 @@ test "packed struct field access via pointer" {
     try S.doTheTest();
     comptime try S.doTheTest();
 }
+
+test "store to comptime field" {
+    if (builtin.zig_backend == .stage1) return error.SkipZigTest;
+
+    {
+        const S = struct {
+            comptime a: [2]u32 = [2]u32{ 1, 2 },
+        };
+        var s: S = .{};
+        s.a = [2]u32{ 1, 2 };
+        s.a[0] = 1;
+    }
+    {
+        const T = struct { a: u32, b: u32 };
+        const S = struct {
+            comptime a: T = T{ .a = 1, .b = 2 },
+        };
+        var s: S = .{};
+        s.a = T{ .a = 1, .b = 2 };
+        s.a.a = 1;
+    }
+}
diff --git a/test/cases/compile_errors/invalid_store_to_comptime_field.zig b/test/cases/compile_errors/invalid_store_to_comptime_field.zig
new file mode 100644
index 0000000000..3bbd9bbaa8
--- /dev/null
+++ b/test/cases/compile_errors/invalid_store_to_comptime_field.zig
@@ -0,0 +1,20 @@
+pub export fn entry() void {
+    const S = struct {
+        comptime a: [2]u32 = [2]u32{ 1, 2 },
+    };
+    var s: S = .{};
+    s.a = [2]u32{ 2, 2 };
+}
+pub export fn entry1() void {
+    const T = struct { a: u32, b: u32 };
+    const S = struct {
+        comptime a: T = T{ .a = 1, .b = 2 },
+    };
+    var s: S = .{};
+    s.a = T{ .a = 2, .b = 2 };
+}
+// error
+// backend=stage2,llvm
+//
+// :6:19: error: value stored in comptime field does not match the default value of the field
+// :14:19: error: value stored in comptime field does not match the default value of the field