TheRealAdamKemp added inline comments.
================
Comment at: include/clang/Basic/AttrDocs.td:122
+* Cannot be returned from a function
+* Cannot be captured by a block
+* Cannot be assigned to a variable
----------------
This may be too restrictive in some cases. Consider this:
```
typedef void (^BlockTy)();
void nonescapingFunc(__attribute__((noescape)) BlockTy);
void callerFunc(__attribute__((noescape)) BlockTy block) {
nonescapingFunc(^{ block(); });
}
```
It sounds like the above code would give an error, but the capturing block is
also nonescaping, which means it should be allowed. This is a useful pattern,
and disallowing it would make these attributes very cumbersome.
The code could also be written like this:
```
typedef void (^BlockTy)();
void nonescapingFunc(__attribute__((noescape)) BlockTy);
void callerFunc(__attribute__((noescape)) BlockTy block) {
BlockTy wrapBlock = ^{
block();
};
nonescapingFunc(wrapBlock);
}
```
Again, I would expect that to not give an error or at least be able to decorate
the declaration of `wrapBlock` to indicate that it is also nonescaping (can
this attribute be applied to locals or only function arguments?).
https://reviews.llvm.org/D32210
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