Bug 2676 – alias parameters not matched in concept if clause

Consider this code: struct A1(T) { } void foo1(X)(X x) if (is(X Y == A1!(U), U)) { static if (is(X Y == A!(U), U)) writeln(U.stringof); } // struct A2(alias T) { } void foo2(X)(X x) if (is(X Y == A2!(U), alias U)) { // static if (is(X Y == A!(U), U)) // writeln(U.stringof); } void bar() {} void main() { A1!(int) a1; foo1(a1); A2!(bar) a2; foo2(a2); } The code with A1 and foo1 illustrates how concept-if works for type template parameters. Similar code that uses aliases instead of types should be matched the same, but it never is. The code compiles A1/foo1 but fails on A2/foo2) with: template test.foo2(X) if (is(X Y == A2!(U),alias U)) cannot deduce template function from argument types !()(A2!(bar))

Fixed dmd 2.026