[Modules] EvaluateAsInitializer executed in every importer when a variable template depends on a conversion operator

[davidstone]

Given the following two module files

export module a;

struct integer {
	explicit operator int() const {
		return 0;
	}
};

template<typename>
int a = static_cast<int>(integer());

void aa() {
	a<void>;
}

import a;

int main() {
}

And compiling them with

clang++ -std=c++20 -x c++-module -fmodule-output=a.pcm --precompile -c a.cpp
clang++ -ftime-trace -std=c++20 -fmodule-file=a=a.pcm -c b.cpp

We see one additional entry in the b.json time trace compared to the output if we delete the line that instantiates the variable template:

{
	"pid": 53878,
	"tid": 53889,
	"ph": "X",
	"ts": 0,
	"dur": 60,
	"name": "Total EvaluateAsInitializer",
	"args": {
		"count": 1,
		"avg ms": 0
	}
}

[llvmbot]

@llvm/issue-subscribers-clang-modules