| Summary: | Inconsistent `this->` required when calling member function in a lambda capturing `this` through another function | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Vittorio Romeo <vittorio.romeo> |
| Component: | c++ | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | daniel.kruegler, jaak, webrown.cpp |
| Priority: | P3 | Keywords: | c++-lambda |
| Version: | 6.0 | ||
| Target Milestone: | 7.0 | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | ||
| Bug Depends on: | |||
| Bug Blocks: | 54367 | ||
More test cases, using minor variations to the code posted above:
With bar() = call([this](auto x){ foo(x); });
clang++ 3.6+ compiles.
g++ 5.2+ does not compile.
With bar() = call([this](auto x){ this->foo(x); });
clang++ 3.6+ compiles.
g++ 5.2+ compiles.
With bar() = call([this](int x){ foo(x); });
clang++ 3.6+ compiles.
g++ 5.2+ compiles.
With bar() = [this](auto x){ foo(x); }(1);
clang++ 3.6+ compiles.
g++ 5.2+ compiles.
Fixed in 7.1.0, we already have testcases. |
Passing a `this`-capturing generic lambda (to a template function) that calls a member function of `this` without an explicit `this->` results in an error: error: cannot call member function 'void Example::foo(int)' without object call([this](auto x){ foo(x); });` If the lambda is not generic, or if the lambda is not passed to any other function but called in place, it compiles without an explicit `this->`. For reference, clang 3.6+ is cool with the code in all situations. --- Minimal example: http://melpon.org/wandbox/permlink/M2eH3FUOentPfieM template<typename TF> void call(TF&& f) { f(1); } struct Example { void foo(int){ } void bar() { call([this](auto x){ foo(x); }); } }; int main() { Example{}.bar(); return 0; } --- StackOverflow question with more examples: http://stackoverflow.com/questions/32097759