overeager typechecking of generic types.

[ChrisDodd]

Consider the following program with a generic function (minor change of testdata/p4_16_samples/function.p4):

T max<T>(in T left, in T right) {
    if (left > right)
        return left;
    return right;
}

control c(out bit<16> b) {
    apply {
        b = max(16w10, 16w12);
    }
}

control ctr(out bit<16> b);
package top(ctr _c);

top(c()) main;

It fails with error message

function2.p4(2): [--Werror=type-error] error: left > right: not defined on T and T
    if (left > right)
        ^^^^^^^^^^^^

However, it would seem to be ok, as the max function is only ever instantiated with bit<16> for T, which should be ok. If you replace the explicitly typed constants as max(10, 12), you get even more errors, even though that should be ok too.