Bug 9143 – template structs with two parameters confuse DMD on multiple instantiations

The following code does not compile. But starts compiling once the first line of function noCall is commented out and the next two line which are logically equivalent are uncommented. It seems compile time parameters of type bool are not propagated well by symbols in certain situations. struct Foo (bool S, bool L) { auto noCall() { Foo!(S, false) x; // compiles if this line commented // static if(S) Foo!(true, false) x; // else Foo!(false, false) x; } this (T) (T other) // constructor if (is (T unused == Foo!(P, Q), bool P, bool Q)) { } } void main() { Foo!(false, true) k = Foo!(false, false)(); }

Earlier I thought the problem occurs for bool parameters. But it seems to be more generic. A more interesting test case: 1. Line 7 fails to compile. 2. There is no problem with line 4, 5, and 6. 3. If we uncomment line 3, compiler does not complain even for line 7. struct Foo (bool L, size_t N) { void baaz () { // bar!(Foo!(false, 2LU))(); // line 3 // bar!(Foo!(true, 2LU))(); // line 4 // bar!(Foo!(L, N))(); // line 5 // bar!(Foo!(true, N))(); // line 6 bar!(Foo!(false, N))(); // line 7 } void bar (T) () if (is(T unused == Foo!(_L, _N), bool _L, size_t _N)) {} } void main() { auto p = Foo!(true, 2LU)(); p.baaz(); }

Since the problem seems to be more generic than I initially reported, and because I am not finding any workarounds now, I am retagging the bug as blocker.