[cfe-dev] hasAncestor() hasDescendant() matchers scope

[Manuel Klimek via cfe-dev]

On Wed, 4 Jul 2018, 17:24 Michael Jabbour via cfe-dev, <
cfe-dev at lists.llvm.org> wrote:

> Hello all,
>
> I am new to clang and I am trying to write a check to familiarize myself
> with AST matchers. I am just looking for a confirmation here. When I
> bind a node within a hasAncestor() matcher, am I guaranteed to get the
> most direct (nearest) ancestor from the current node?
>
> Consider the following example:
>
> class MyClass {
> public:
>   void myClassOp() {         //<-- another parent CXXMemberDecl
>     class NestedClass {
>       void nestedClassOp() { //<-- parent CXXMemberDecl
>         (void) this;         //<-- CXXThisExpr
>       }
>     };
>   }
> };
>
> I get the most direct ancestor (the desired behavior) when using a
> matcher like:
>
>  cxxThisExpr(hasAncestor(cxxMethodDecl().bind("method"))).bind("this")
>
> My question is: Is this behavior always guaranteed? or am I just being
> lucky here?
>

It's guaranteed if there is a single line of ancestry, but keep in mind
that nodes can have multiple parents :)


>
> Thanks,
>
> Mike
>
>
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