LDC crashes if imported module contains error

[redstar]

With the files thisbug.d

module thisbug;

import thisbuginc;

Foo create()
{
    return new Foo();
}

and thisbuginc.d

module thisbuginc;

//import std.algorithm;

class Foo
{
    struct Bar
    {
        int opCmp(ref const Bar rhs) const
        { return sortOrder(this, rhs); }

        private final static int sortOrder(ref const Bar a, ref const Bar b) {
            return 0;
        }
    }

    auto sortedBars(Bar[] bars) {
        return sort(bars);
    }
}

the command ldc2 -c thisbug.d prints an error message and crashes with release 0.12.0 (bad). If the merge-2.064 branch is used then ldc crashes with no error message printed (worse).

DMD compiles the module without problems.

A deeper analysis shows that the buggy types are referenced during vtable construction in the codegen phase. Because of the error, semantic3() has not been run. Then missing information leads to the crash.
DMD does not need the type information for the vtable construction and therefore compiles fine.

If you fix the bug (remove the comment) then ldc compiles the module, too.

[dnadlinger]

In Git master, this now properly produces

thisbuginc.d(18): Error: undefined identifier sort

(I don't think it is a bug that we emit an error message when an imported module is broken.)