Teach RAV to visit parameter variable declarations of implicit functions. Fixes PR16182.

Normally RAV visits parameter variable declarations of a function by traversing the TypeLoc of
the parameter declarations. However, for implicit functions, their parameters don't have any
TypeLoc, because they are implicit.

So for implicit functions, we visit their parameter variable declarations by traversing them through
the function declaration, and visit them accordingly.

Reviewed by Richard Smith and Manuel Klimek.

llvm-svn: 190528

1 files changed, 25 insertions, 0 deletions

diff --git a/clang/unittests/Tooling/RecursiveASTVisitorTest.cpp b/clang/unittests/Tooling/RecursiveASTVisitorTest.cpp
index b1d6f4a37c0..b3a8915a59d 100644
--- a/clang/unittests/Tooling/RecursiveASTVisitorTest.cpp
+++ b/clang/unittests/Tooling/RecursiveASTVisitorTest.cpp
@@ -37,6 +37,17 @@ public:
  }
 };
 
+class ParmVarDeclVisitorForImplicitCode :
+  public ExpectedLocationVisitor<ParmVarDeclVisitorForImplicitCode> {
+public:
+  bool shouldVisitImplicitCode() const { return true; }
+
+  bool VisitParmVarDecl(ParmVarDecl *ParamVar) {
+    Match(ParamVar->getNameAsString(), ParamVar->getLocStart());
+    return true;
+  }
+};
+
 class CXXMemberCallVisitor
   : public ExpectedLocationVisitor<CXXMemberCallVisitor> {
 public:
@@ -144,6 +155,20 @@ public:
   }
 };
 
+// Test RAV visits parameter variable declaration of the implicit
+// copy assignment operator.
+TEST(RecursiveASTVisitor, VisitsParmVarDeclForImplicitCode) {
+  ParmVarDeclVisitorForImplicitCode Visitor;
+  // Match parameter variable name of implicit copy assignment operator.
+  // This parameter name does not have a valid IdentifierInfo, and shares
+  // same SourceLocation with its class declaration, so we match an empty name
+  // with the class' source location.
+  Visitor.ExpectMatch("", 1, 7);
+  EXPECT_TRUE(Visitor.runOver(
+    "class X {};\n"
+    "void foo(X a, X b) {a = b;}"));
+}
+
 TEST(RecursiveASTVisitor, VisitsBaseClassDeclarations) {
   TypeLocVisitor Visitor;
   Visitor.ExpectMatch("class X", 1, 30);