Brush Up Language Features

Mangling Scheme

Consistently stop encoding return type of parent functions

Currently, for function local symbols, the return types of their parent functions are normally mangled into the name.

module test;
int foo()
{
    void bar() {
        struct S {}
        pragma(msg, S.mangleof);
        // S 4test 3fooFZi 3barMFZv 1S
        //               |        |
        //      int of foo        |
        //              void of bar
    }
    return 0;
}

But, for voldemort types, we already has an exception of the rule.

module test;
auto foo()
{
    auto bar() {
        struct S {}
        pragma(msg, S.mangleof);
        //         S 4test 3fooFZ 3barMFZ 1S
        //                      |       |
        // no return type for foo       |
        //         no return type for bar
        return S();
    }
    return 0;
}

The change was introduced to fix Issue 8847. https://d.puremagic.com/issues/show_bug.cgi?id=8847

In D, functions cannot be overloaded based on the return types.

void foo() {}
int foo() {}   // wrong overloading of foo

So the return type mangling is essentially redundant.

module test;
void foo()    { struct S {}  pragma(msg, "1: ", S.mangleof); }
void foo(int) { struct S {}  pragma(msg, "2: ", S.mangleof); }

Current result;

1: S4test3fooFZv1S
2: S4test3fooFiZv1S

Modified result:

1: S4test3fooFZ1S
2: S4test3fooFiZ1S
// --> The two local symbols S still have unique mangled names.