fix @bitCast of packed struct literal

closes #3042

src/ir.cpp

@@ -14802,6 +14802,9 @@ static IrInstruction *ir_resolve_result_raw(IrAnalyze *ira, IrInstruction *suspe
                 return ira->codegen->invalid_instruction;
             }
             uint64_t parent_ptr_align = get_ptr_align(ira->codegen, parent_ptr_type);
+            if ((err = type_resolve(ira->codegen, value_type, ResolveStatusAlignmentKnown))) {
+                return ira->codegen->invalid_instruction;
+            }
             ZigType *ptr_type = get_pointer_to_type_extra(ira->codegen, value_type,
                     parent_ptr_type->data.pointer.is_const, parent_ptr_type->data.pointer.is_volatile, PtrLenSingle,
                     parent_ptr_align, 0, 0, parent_ptr_type->data.pointer.allow_zero);

test/stage1/behavior/bitcast.zig

@@ -131,3 +131,11 @@ test "bitcast literal [4]u8 param to u32" {
     const ip = @bitCast(u32, [_]u8{ 255, 255, 255, 255 });
     expect(ip == maxInt(u32));
 }
+
+test "bitcast packed struct literal to byte" {
+    const Foo = packed struct {
+        value: u8,
+    };
+    const casted = @bitCast(u8, Foo{ .value = 0xF });
+    expect(casted == 0xf);
+}