import std.conv;
void main()
{
    int x = to!int("7");
}

On v2.045, v2.046 and v2.047:
phobos\std\format.d(1882): Error: template std.array.Appender!(string).Appender.put(U) if (isImplicitlyConvertible!(U,T) || isSomeChar!(T) && isSomeChar!(U)) does not match any function template declaration
phobos\std\format.d(1882): Error: template std.array.Appender!(string).Appender.put(U) if (isImplicitlyConvertible!(U,T) || isSomeChar!(T) && isSomeChar!(U)) cannot deduce template function from argument types !()(char[])

On v2.048:
phobos\std\algorithm.d(2890): Error: cast(string)_param_1 is not an lvalue