[cfe-commits] [PATCH] Matchers for Types, QualTypes and TypeLocs

Manuel Klimek klimek at google.com
Wed Oct 17 00:56:39 PDT 2012

Comment at: lib/ASTMatchers/ASTMatchFinder.cpp:560
@@ +559,3 @@
+  // RecursiveASTVisitor by itself would only visit the TypeLocs, not the
+  // contained types.
+  match(TypeLocNode);
Daniel Jasper wrote:
> Manuel Klimek wrote:
> > The question is: why do we want to traverse the Types here?
> We do not traverse the Types. We only match them. So basically, whenever you find a TypeLoc hierarchy in the AST, there is a corresponding Type hierarchy. The RecursiveASTVisitor does not visit both, as the TypeLoc is sort of a superset of the Type. However, when matching, we also want to match the contained types, if we happen to have a type-matcher, no?
> So, what we basically do is traverse the hierarchy once and try to match both Types and TypeLocs.
Yes, sorry, I meant "the question is: why do we want to match the Types here".

So, here's a proposal for the comment:
The RecursiveASTVisitor only visits types if they're not within TypeLocs. We still want to find those types via matchers, so we match them here. Note that the TypeLocs are structurally a shadow-hierarchy to the expressed type, so we visit all involved parts of a compound type when matching on each TypeLoc.


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