The following program compiles (bar uses a default type for T, baz relies on IFTI):
---
void bar(T = double)(int i) {}
void baz(T)(int i, T t) {}
void main() {
    bar(2);
    baz(3, "baz");
}
---

But if typeof() is used instead of explicitly specifying int, neither calls to bar and baz work any longer:
---
int a;
void bar(T = double)(typeof(a) i) {}
void baz(T)(typeof(a) i, T t) {}
void main() {
    bar(2);  // Does not compile.
    baz(3, "baz"); // Does not compile.
}
---

The respective error messages are:
Error: template test.bar(T = double) does not match any function template declaration
Error: template test.bar(T = double) cannot deduce template function from argument types !()(int)
and
Error: template test.baz(T) does not match any function template declaration
Error: template test.baz(T) cannot deduce template function from argument types !()(int,string).

If the template parameter is specified explicitly, however, both of the examples work again:
---
int a;
void bar(T = double)(typeof(a) i) {}
void baz(T)(typeof(a) i, T t) {}
void main() {
    bar!double(2);
    baz!string(3, "baz");
}
---

DMD from Git master at b7133502.