Type checker fails to reject compile-time out-of-bounds access to a header stack

[jaehyun1ee]

As mentioned in Section 8.18, any reference to an element of a header stack hs[index] where index is a compile-time known value must give an error at compile time if the value of the index is out of range.

The spec disallows an out-of-bounds access to a header stack, if the index is a compile-time known value.

However, p4c fails to reject minsize.p4.

typedef bit<32> T;

header H {}

control c(out bit<32> v) {
    apply
    {
        bit<32> b;
        H[0] h;

        v = b.minSizeInBits() + T.minSizeInBits() + b.maxSizeInBits() + T.maxSizeInBits() + h[0].minSizeInBits();
        // h[0] is an out-of-bounds access
    }
}

const int w = T.maxSizeInBits();

control cproto(out bit<32> v);
package top(cproto _c);

top(c()) main;