[cfe-commits] [PATCH] ThisExpr matcher

[Gábor Horváth]

Hi djasper, klimek,

Given a snippet like :
struct foo {
  int i;
  int f() { return i; }
};

I know no way to determine if we match where i is used determine if i is a member of foo or not. Or if we match the fieldDecl of foo, we can not match where i is used.

For other similar cases there is declRefExpr, but it is not usable in this scenario, however thisExpr can be a solution for this case.

For example to match functor predicates that are not stateless I'm using something like:
thisExpr(hasAncestor(methodDecl(allOf(hasName("operator()"), returns(asString("_Bool")))))).bind("id")

http://llvm-reviews.chandlerc.com/D70

Files:
  include/clang/ASTMatchers/ASTMatchers.h
  unittests/ASTMatchers/ASTMatchersTest.cpp

Index: include/clang/ASTMatchers/ASTMatchers.h
===================================================================
--- include/clang/ASTMatchers/ASTMatchers.h
+++ include/clang/ASTMatchers/ASTMatchers.h
@@ -546,6 +546,18 @@
   Stmt,
   CXXConstructExpr> constructExpr;
 
+/// \brief Matches implicit and explicit this expressions.
+///
+/// Example matches "this" before i.
+///     (matcher = thisExpr())
+/// \code
+/// struct foo {
+///   int i;
+///   int f() { return i; }
+/// };
+/// \endcode
+const internal::VariadicDynCastAllOfMatcher<Stmt, CXXThisExpr> thisExpr;
+
 /// \brief Matches nodes where temporaries are created.
 ///
 /// Example matches FunctionTakesString(GetStringByValue())
Index: unittests/ASTMatchers/ASTMatchersTest.cpp
===================================================================
--- unittests/ASTMatchers/ASTMatchersTest.cpp
+++ unittests/ASTMatchers/ASTMatchersTest.cpp
@@ -1333,6 +1333,13 @@
                  Constructor1Arg));
 }
 
+TEST(Matcher,ThisExpr) {
+  EXPECT_TRUE(
+      matches("struct X { int a; int f () { return a; } };", thisExpr()));
+  EXPECT_TRUE(
+      notMatches("struct X { int f () { int a; return a; } };", thisExpr()));
+}
+
 TEST(Matcher, BindTemporaryExpression) {
   StatementMatcher TempExpression = bindTemporaryExpr();
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