I'm not sure whether the following a compiler/language bug or a Phobos bug, but it's definitely some kind of bug:
auto s = "abc"; immutable t = "def"; writeln(typeid(s)); // immutable(char)[] writeln(typeid(t)); // immutable(immutable(char)[]) // (what is this supposed to mean?!) char ch = 'c'; bool b = canFind(s, ch); // OK bool c = canFind(t, ch); // Compile error?? The compile error is: test.d:11: Error: template std.algorithm.canFind(alias pred = "a == b",Range,V) if (is(typeof(find!(pred)(range,value)))) does not match any function template declaration test.d:11: Error: template std.algorithm.canFind(alias pred = "a == b",Range,V) if (is(typeof(find!(pred)(range,value)))) cannot deduce template function from argument types !()(immutable(char[]),char) Can somebody explain what's going on here? T -- There are two ways to write error-free programs; only the third one works.