Merge pull request #23263 from mlugg/comptime-field-ptr

Sema: fix pointers to comptime fields of comptime-known aggregate pointers

test/behavior/tuple.zig

@@ -602,3 +602,21 @@ test "empty union in tuple" {
     try std.testing.expectEqualStrings("0", info.@"struct".fields[0].name);
     try std.testing.expect(@typeInfo(info.@"struct".fields[0].type) == .@"union");
 }
+
+test "field pointer of underaligned tuple" {
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
+    const S = struct {
+        fn doTheTest() !void {
+            const T = struct { u8, u32 };
+            var val: T align(2) = .{ 1, 2 };
+
+            comptime assert(@TypeOf(&val[0]) == *u8); // `u8` field pointer isn't overaligned
+            comptime assert(@TypeOf(&val[1]) == *align(2) u32); // `u32` field pointer is correctly underaligned
+
+            try expect(val[0] == 1);
+            try expect(val[1] == 2);
+        }
+    };
+    try S.doTheTest();
+    try comptime S.doTheTest();
+}