compile errors for generic function instantiation in zig

output.txt

./test.zig:2:7: error: incompatible types: 'i32' and 'f64'
    a + b
      ^
./test.zig:6:8: note: called from here
    add(a, b)
       ^
./test.zig:10:8: note: called from here
    foo(a, b)
       ^
./test.zig:14:8: note: called from here
    bar(f64, 123, 456)
       ^
./test.zig:2:5: note: type 'i32' here
    a + b
    ^
./test.zig:2:9: note: type 'f64' here
    a + b
        ^

test.zig

fn add(a: var, b: var) -> @typeOf(a) {
    a + b
}

fn foo(a: var, b: var) -> i32 {
    add(a, b)
}

fn bar(comptime T: type, a: i32, b: T) -> i32 {
    foo(a, b)
}

fn baz() -> i32 {
    bar(f64, 123, 456)
}