gcc/testsuite/gdc.test/fail_compilation/fail11163.d

/*
TEST_OUTPUT:
---
fail_compilation/fail11163.d(12): Error: cannot implicitly convert expression `foo()` of type `int[]` to `immutable(int[])`
fail_compilation/fail11163.d(13):        while evaluating pragma(msg, a)
---
*/
int[] foo() {
    return [1];
}
void main() {
    immutable a = foo();
    pragma(msg, a);
}