Commit f92e7bed7b6b83b2cdfe2bfed047e3a7bcdd2116 | zig

Closes #13398

2 files changed, 18 insertions(+), 7 deletions(-)

src/type.zig+5-7

 @@ -3574,15 +3574,13 @@ pub const Type = extern union {
             .u128, .i128, .f128 => return 128,
             .@"struct" => {
-                if (sema_kit) |sk| _ = try sk.sema.resolveTypeFields(sk.block, sk.src, ty);
+                const struct_obj = ty.castTag(.@"struct").?.data;
-                if (ty.containerLayout() != .Packed) {
+                if (struct_obj.layout != .Packed) {
                     return (try ty.abiSizeAdvanced(target, if (sema_kit) |sk| .{ .sema_kit = sk } else .eager)).scalar * 8;
                 }
-                var total: u64 = 0;
+                if (sema_kit) |sk| _ = try sk.sema.resolveTypeLayout(sk.block, sk.src, ty);
-                for (ty.structFields().values()) |field| {
+                assert(struct_obj.haveLayout());
-                    total += try bitSizeAdvanced(field.ty, target, sema_kit);
+                return try struct_obj.backing_int_ty.bitSizeAdvanced(target, sema_kit);
-                }
-                return total;
             },
             .tuple, .anon_struct => {

test/cases/compile_errors/bitsize_of_packed_struct_checks_backing_int_ty.zig created+13

...	@@ -0,0 +1,13 @@
1	const Foo = packed struct(u32) {
2	x: u1,
3	};
4	fn bar(_: Foo) callconv(.C) void {}
5	pub export fn entry() void {
6	bar(.{ .x = 0 });
7	}
8
9	// error
10	// backend=stage2
11	// target=native
12	//
13	// :1:27: error: backing integer type 'u32' has bit size 32 but the struct fields have a total bit size of 1