Fix Issue 19661 - DMD 2.084.0 SIGSEGV in std.traits.isFunction

[RazvanN7]

module test;

public immutable bool testModule = testFunctionMembers!"test";    // line 3

public void testFunctionMembers(string module_)() {
    import std.traits : isFunction;
    mixin(`import dmodule = ` ~ module_ ~ `;`);
    foreach(member; __traits(allMembers, dmodule)) {
        const bool isfunc = isFunction!(__traits(getMember, dmodule, member));
    }
}

Fixing the regression for this code led to outputting the error message : "Error: cannot implicitly convert expression of type void to immutable(bool)" ; the line number is missing, but it refers to line 3.
I wanted to fix that also by adding the line number to the error, but noticed that this code compiles fine:

immutable bool b = void;

In light of this example, I modified the code so that when an ExpInitializer that is evaluated to a VoidExpression is encountered, a VoidInitializer is returned. This made the code in the original bug post compile successfully, which I believe is the right fix.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	19661	regression	DMD 2.084.0 SIGSEGV in std.traits.isFunction

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub fetch digger
dub run digger -- build "master + dmd#9652"

[wilzbach]

stable?

[RazvanN7]

Tried to, but I get conflicts.

[ghost]

In light of this example, I modified the code so that when an ExpInitializer that is evaluated to a VoidExpression is encountered, a VoidInitializer is returned. This made the code in the original bug post compile successfully, which I believe is the right fix.

No error message is not good at all. Also this is not like a void init, the test case is more like

immutable bool b = test();
void test(){}

which outputs the impl. conv error I managed to get in the previous fix attempt.

[Geod24]

void initialization != initialization with an expression of type void

[RazvanN7]

@Geod24 @Basile-z I updated the patch. Now if any expressions are evaluated to void after ctfe an error will be issued.

[ghost]

I see a small progress compared to my fix, i.e the line numbers, so this is good to my eyes

[RazvanN7]

ping @Geod24

void init problem fixed.

[RazvanN7]

The Out of memory error is unrelated to this PR, although this should be a sign that dmd is using waaaaaaay too much memory; I just compiled the vibe.d unittests and my computer froze for 1-2 minutes; I have 4GB, I know it's not that much, but still...