comptime-known `undefined` values can coerce to any type, even when not of type `@Type(.Undefined)`

[mlugg]

Zig Version

0.11.0-dev.811+8ff9284c4

Steps to Reproduce and Observed Behavior

pub fn main() void {
    const x: []u8 = undefined;
    const y: f32 = x;
    _ = y;
}

The compilation completes successfully. Adding @compileLog(@TypeOf(x)) (and the same for y) shows that the types are as expected (nothing has become @Type(.Undefined)):

[mlugg@vega test]$ zig run test.zig
test.zig:3:5: error: found compile log statement
    @compileLog(@TypeOf(x));
    ^~~~~~~~~~~~~~~~~~~~~~~

Compile Log Output:
@as(type, []u8)
@as(type, f32)

Expected Behavior

The compilation should fail with this error:

test.zig:3:20: error: expected type 'f32', found '[]u8'
    const y: f32 = x;