Add new matchers for dependent names in templates

[steveire]

Update

[aaron.ballman]

clang/include/clang/ASTMatchers/ASTMatchers.h

2838

Missing full stop at the end of the comment.

2859

This will allow users to match on members that don't have identifiers -- is that intentional? If not, my recommendation is to use something like:

if (const IdentifierInfo *II = Node.getMember().getAsIdentifierInfo())
  return II->isStr(N);
return false;

Either way, we should document and test what the expected behavior is for things like constructors/destructors, overloaded operators, and the likes. (But we don't have to test every kind of odd declaration name.)

2898

Similar concerns here about matching members without identifiers.

2902

I assume this is a const auto & and not a value type? If so, please update the type.

2903

const auto *

2904

!isa<FieldDecl, CXXMethodDecl, VarDecl>(ND)

2906–2908

return ND->getName() != MemberName;

[steveire]

Update

clang/include/clang/ASTMatchers/ASTMatchers.h

2859

I was not able to demonstrate the problem with a test: https://godbolt.org/z/3Grd1b

Can you be more specific?

[aaron.ballman]

clang/include/clang/ASTMatchers/ASTMatchers.h

2859

I was thinking of something along these lines: https://godbolt.org/z/K8serj

[steveire]

Update

[steveire]

clang/include/clang/ASTMatchers/ASTMatchers.h

2859

Added a test for that.

[aaron.ballman]

LGTM!

clang/include/clang/ASTMatchers/ASTMatchers.h

2859

Thanks!

clang/docs/LibASTMatchersReference.html

Given
   S(int) -> S<true> // #5
   explicit S(double) -> S<false> // #6
 cxxConstructorDecl(isExplicit()) will match #2 and #8, but not #1, #7 or #9.
 cxxConversionDecl(isExplicit()) will match #4, but not #3.
 cxxDeductionGuideDecl(isExplicit()) will match #6, but not #5.
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXDependentScopeMemberExpr.html">CXXDependentScopeMemberExpr</a>&gt;</td><td class="name" onclick="toggle('hasMemberName0')"><a name="hasMemberName0Anchor">hasMemberName</a></td><td>std::string N</td></tr>
+<tr><td colspan="4" class="doc" id="hasMemberName0"><pre>Matches template-dependent, but known, member names
+
+In template declarations, dependent members are not resolved and so can
+not be matched to particular named declarations.
+
+This matcher allows to match on the known name of members.
+
+Given
+  template &lt;typename T&gt;
+  struct S {
+      void mem();
+  };
+  template &lt;typename T&gt;
+  void x() {
+      S&lt;T&gt; s;
+      s.mem();
+  }
+cxxDependentScopeMemberExpr(hasMemberName("mem")) matches `s.mem()`
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXDependentScopeMemberExpr.html">CXXDependentScopeMemberExpr</a>&gt;</td><td class="name" onclick="toggle('isArrow2')"><a name="isArrow2Anchor">isArrow</a></td><td></td></tr>
 <tr><td colspan="4" class="doc" id="isArrow2"><pre>Matches member expressions that are called with '-&gt;' as opposed
 to '.'.
 
 Member calls on the implicit this pointer match as called with '-&gt;'.
 
 Given
   class Y {
memberExpr(isArrow())
   matches this-&gt;x, x, y.x, a, this-&gt;b
 cxxDependentScopeMemberExpr(isArrow())
   matches this-&gt;m
 unresolvedMemberExpr(isArrow())
   matches this-&gt;f&lt;T&gt;, f&lt;T&gt;
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXDependentScopeMemberExpr.html">CXXDependentScopeMemberExpr</a>&gt;</td><td class="name" onclick="toggle('memberHasSameNameAsBoundNode0')"><a name="memberHasSameNameAsBoundNode0Anchor">memberHasSameNameAsBoundNode</a></td><td>std::string BindingID</td></tr>
+<tr><td colspan="4" class="doc" id="memberHasSameNameAsBoundNode0"><pre>Matches template-dependent, but known, member names against an already-bound
+node
+
+In template declarations, dependent members are not resolved and so can
+not be matched to particular named declarations.
+
+This matcher allows to match on the name of already-bound VarDecl, FieldDecl
+and CXXMethodDecl nodes.
+
+Given
+  template &lt;typename T&gt;
+  struct S {
+      void mem();
+  };
+  template &lt;typename T&gt;
+  void x() {
+      S&lt;T&gt; s;
+      s.mem();
+  }
+The matcher
+@code
+cxxDependentScopeMemberExpr(
+  hasObjectExpression(declRefExpr(hasType(templateSpecializationType(
+      hasDeclaration(classTemplateDecl(has(cxxRecordDecl(has(
+          cxxMethodDecl(hasName("mem")).bind("templMem")
+          )))))
+      )))),
+  memberHasSameNameAsBoundNode("templMem")
+  )
+@endcode
+first matches and binds the @c mem member of the @c S template, then
+compares its name to the usage in @c s.mem() in the @c x function template
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXMethodDecl.html">CXXMethodDecl</a>&gt;</td><td class="name" onclick="toggle('isConst0')"><a name="isConst0Anchor">isConst</a></td><td></td></tr>
 <tr><td colspan="4" class="doc" id="isConst0"><pre>Matches if the given method declaration is const.
 
 Given
 struct A {
   void foo() const;
   void bar();
 };
But given
   template &lt;&gt; class X&lt;A&gt; {}; X&lt;A&gt; x;
 cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
   does not match, as X&lt;A&gt; is an explicit template specialization.
 
 Usable as: Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html">FunctionDecl</a>&gt;, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1VarDecl.html">VarDecl</a>&gt;, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXRecordDecl.html">CXXRecordDecl</a>&gt;
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXUnresolvedConstructExpr.html">CXXUnresolvedConstructExpr</a>&gt;</td><td class="name" onclick="toggle('argumentCountIs2')"><a name="argumentCountIs2Anchor">argumentCountIs</a></td><td>unsigned N</td></tr>
+<tr><td colspan="4" class="doc" id="argumentCountIs2"><pre>Checks that a call expression or a constructor call expression has
+a specific number of arguments (including absent default arguments).
+
+Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
+  void f(int x, int y);
+  f(0, 0);
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CallExpr.html">CallExpr</a>&gt;</td><td class="name" onclick="toggle('argumentCountIs0')"><a name="argumentCountIs0Anchor">argumentCountIs</a></td><td>unsigned N</td></tr>
 <tr><td colspan="4" class="doc" id="argumentCountIs0"><pre>Checks that a call expression or a constructor call expression has
 a specific number of arguments (including absent default arguments).
 
 Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
   void f(int x, int y);
   f(0, 0);
 </pre></td></tr>

 
 
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCInterfaceDecl.html">ObjCInterfaceDecl</a>&gt;</td><td class="name" onclick="toggle('isSameOrDerivedFrom3')"><a name="isSameOrDerivedFrom3Anchor">isSameOrDerivedFrom</a></td><td>std::string BaseName</td></tr>
 <tr><td colspan="4" class="doc" id="isSameOrDerivedFrom3"><pre>Overloaded method as shortcut for
 isSameOrDerivedFrom(hasName(...)).
 </pre></td></tr>
 
 
-<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('argumentCountIs2')"><a name="argumentCountIs2Anchor">argumentCountIs</a></td><td>unsigned N</td></tr>
-<tr><td colspan="4" class="doc" id="argumentCountIs2"><pre>Checks that a call expression or a constructor call expression has
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('argumentCountIs3')"><a name="argumentCountIs3Anchor">argumentCountIs</a></td><td>unsigned N</td></tr>
+<tr><td colspan="4" class="doc" id="argumentCountIs3"><pre>Checks that a call expression or a constructor call expression has
 a specific number of arguments (including absent default arguments).
 
 Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
   void f(int x, int y);
   f(0, 0);
 </pre></td></tr>
 
 

 For ObjectiveC, given
   @interface I - (void) f:(int) y; @end
   void foo(I *i) { [i f:12]; }
 objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
   matches [i f:12]
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXUnresolvedConstructExpr.html">CXXUnresolvedConstructExpr</a>&gt;</td><td class="name" onclick="toggle('hasArgument2')"><a name="hasArgument2Anchor">hasArgument</a></td><td>unsigned N, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
+<tr><td colspan="4" class="doc" id="hasArgument2"><pre>Matches the n'th argument of a call expression or a constructor
+call expression.
+
+Example matches y in x(y)
+    (matcher = callExpr(hasArgument(0, declRefExpr())))
+  void x(int) { int y; x(y); }
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CallExpr.html">CallExpr</a>&gt;</td><td class="name" onclick="toggle('callee1')"><a name="callee1Anchor">callee</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="callee1"><pre>Matches if the call expression's callee's declaration matches the
 given matcher.
 
 Example matches y.x() (matcher = callExpr(callee(
                                    cxxMethodDecl(hasName("x")))))
   class Y { public: void x(); };
   void z() { Y y; y.x(); }

 For ObjectiveC, given
   @interface I - (void) f:(int) y; @end
   void foo(I *i) { [i f:12]; }
 objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
   matches [i f:12]
 </pre></td></tr>
 
 
-<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('hasArgument2')"><a name="hasArgument2Anchor">hasArgument</a></td><td>unsigned N, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
-<tr><td colspan="4" class="doc" id="hasArgument2"><pre>Matches the n'th argument of a call expression or a constructor
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('hasArgument3')"><a name="hasArgument3Anchor">hasArgument</a></td><td>unsigned N, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
+<tr><td colspan="4" class="doc" id="hasArgument3"><pre>Matches the n'th argument of a call expression or a constructor
 call expression.
 
 Example matches y in x(y)
     (matcher = callExpr(hasArgument(0, declRefExpr())))
   void x(int) { int y; x(y); }
 </pre></td></tr>
 
 

clang/include/clang/ASTMatchers/ASTMatchers.h

 ///   anyOf(hasOverloadedOperatorName("+"), hasOverloadedOperatorName("-"))
 extern const internal::VariadicFunction<
     internal::PolymorphicMatcherWithParam1<
         internal::HasOverloadedOperatorNameMatcher, std::vector<std::string>,
         AST_POLYMORPHIC_SUPPORTED_TYPES(CXXOperatorCallExpr, FunctionDecl)>,
     StringRef, internal::hasAnyOverloadedOperatorNameFunc>
     hasAnyOverloadedOperatorName;
 
+/// Matches template-dependent, but known, member names.
+///
+/// In template declarations, dependent members are not resolved and so can
+/// not be matched to particular named declarations.
+///
+/// This matcher allows to match on the known name of members.
+///
+/// Given
+/// \code
+///   template <typename T>
+///   struct S {
+///       void mem();
+///   };
+///   template <typename T>
+///   void x() {
+///       S<T> s;
+///       s.mem();
+///   }
+/// \endcode
+/// \c cxxDependentScopeMemberExpr(hasMemberName("mem")) matches `s.mem()`
+AST_MATCHER_P(CXXDependentScopeMemberExpr, hasMemberName, std::string, N) {
+  return Node.getMember().getAsString() == N;
+}
+
+/// Matches template-dependent, but known, member names against an already-bound
+/// node
+///
+/// In template declarations, dependent members are not resolved and so can
+/// not be matched to particular named declarations.
+///
+/// This matcher allows to match on the name of already-bound VarDecl, FieldDecl
+/// and CXXMethodDecl nodes.
+///
+/// Given
+/// \code
+///   template <typename T>
+///   struct S {
+///       void mem();
+///   };
+///   template <typename T>
+///   void x() {
+///       S<T> s;
+///       s.mem();
+///   }
+/// \endcode
+/// The matcher
+/// @code
+/// \c cxxDependentScopeMemberExpr(
+///   hasObjectExpression(declRefExpr(hasType(templateSpecializationType(
+///       hasDeclaration(classTemplateDecl(has(cxxRecordDecl(has(
+///           cxxMethodDecl(hasName("mem")).bind("templMem")
+///           )))))
+///       )))),
+///   memberHasSameNameAsBoundNode("templMem")
+///   )
+/// @endcode
+/// first matches and binds the @c mem member of the @c S template, then
+/// compares its name to the usage in @c s.mem() in the @c x function template
+AST_MATCHER_P(CXXDependentScopeMemberExpr, memberHasSameNameAsBoundNode,
+              std::string, BindingID) {
+  auto MemberName = Node.getMember().getAsString();
+
+  return Builder->removeBindings(
+      [this, MemberName](const BoundNodesMap &Nodes) {
+        const auto &BN = Nodes.getNode(this->BindingID);
+        if (const auto *ND = BN.get<NamedDecl>()) {
+          if (!isa<FieldDecl, CXXMethodDecl, VarDecl>(ND))
+            return true;
+          return ND->getName() != MemberName;
+        }
+        return true;
+      });
+}
+
 /// Matches C++ classes that are directly or indirectly derived from a class
 /// matching \c Base, or Objective-C classes that directly or indirectly
 /// subclass a class matching \c Base.
 ///
 /// Note that a class is not considered to be derived from itself.
 ///
 /// Example matches Y, Z, C (Base == hasName("X"))
 /// \code

clang/lib/ASTMatchers/Dynamic/Registry.cpp

RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(hasInitializer);
   REGISTER_MATCHER(hasInitStatement);
   REGISTER_MATCHER(hasKeywordSelector);
   REGISTER_MATCHER(hasLHS);
   REGISTER_MATCHER(hasLocalQualifiers);
   REGISTER_MATCHER(hasLocalStorage);
   REGISTER_MATCHER(hasLoopInit);
   REGISTER_MATCHER(hasLoopVariable);
+  REGISTER_MATCHER(hasMemberName);
   REGISTER_MATCHER(hasMethod);
   REGISTER_MATCHER(hasName);
   REGISTER_MATCHER(hasNullSelector);
   REGISTER_MATCHER(hasObjectExpression);
   REGISTER_MATCHER(hasOperands);
   REGISTER_MATCHER(hasOperatorName);
   REGISTER_MATCHER(hasOverloadedOperatorName);
   REGISTER_MATCHER(hasParameter);
RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(lValueReferenceType);
   REGISTER_MATCHER(labelDecl);
   REGISTER_MATCHER(labelStmt);
   REGISTER_MATCHER(lambdaExpr);
   REGISTER_MATCHER(linkageSpecDecl);
   REGISTER_MATCHER(materializeTemporaryExpr);
   REGISTER_MATCHER(member);
   REGISTER_MATCHER(memberExpr);
+  REGISTER_MATCHER(memberHasSameNameAsBoundNode);
   REGISTER_MATCHER(memberPointerType);
   REGISTER_MATCHER(namedDecl);
   REGISTER_MATCHER(namesType);
   REGISTER_MATCHER(namespaceAliasDecl);
   REGISTER_MATCHER(namespaceDecl);
   REGISTER_MATCHER(nestedNameSpecifier);
   REGISTER_MATCHER(nestedNameSpecifierLoc);
   REGISTER_MATCHER(nonTypeTemplateParmDecl);

clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

EXPECT_TRUE(matches("class X { public: X(int); }; void x() { X x = X(0); }",
                       Constructor1Arg));
   EXPECT_TRUE(matches("class X { public: X(int); }; void x() { X x = 0; }",
                       Constructor1Arg));
   EXPECT_TRUE(
       notMatches("class X { public: X(int, int); }; void x() { X x(0, 0); }",
                  Constructor1Arg));
 }
 
+TEST(ASTMatchersTest, NamesMember_CXXDependentScopeMemberExpr) {
+
+  // Member functions:
+  {
+    auto Code = "template <typename T> struct S{ void mem(); }; template "
+                "<typename T> void x() { S<T> s; s.mem(); }";
+
+    EXPECT_TRUE(matches(
+        Code,
+        cxxDependentScopeMemberExpr(
+            hasObjectExpression(declRefExpr(hasType(templateSpecializationType(
+                hasDeclaration(classTemplateDecl(has(cxxRecordDecl(
+                    has(cxxMethodDecl(hasName("mem")).bind("templMem")))))))))),
+            memberHasSameNameAsBoundNode("templMem"))));
+
+    EXPECT_TRUE(
+        matches(Code, cxxDependentScopeMemberExpr(hasMemberName("mem"))));
+  }
+
+  // Member variables:
+  {
+    auto Code = "template <typename T> struct S{ int mem; }; template "
+                "<typename T> void x() { S<T> s; s.mem; }";
+
+    EXPECT_TRUE(
+        matches(Code, cxxDependentScopeMemberExpr(hasMemberName("mem"))));
+
+    EXPECT_TRUE(matches(
+        Code,
+        cxxDependentScopeMemberExpr(
+            hasObjectExpression(declRefExpr(hasType(templateSpecializationType(
+                hasDeclaration(classTemplateDecl(has(cxxRecordDecl(
+                    has(fieldDecl(hasName("mem")).bind("templMem")))))))))),
+            memberHasSameNameAsBoundNode("templMem"))));
+  }
+
+  // static member variables:
+  {
+    auto Code = "template <typename T> struct S{ static int mem; }; template "
+                "<typename T> void x() { S<T> s; s.mem; }";
+
+    EXPECT_TRUE(
+        matches(Code, cxxDependentScopeMemberExpr(hasMemberName("mem"))));
+
+    EXPECT_TRUE(matches(
+        Code,
+        cxxDependentScopeMemberExpr(
+            hasObjectExpression(declRefExpr(hasType(templateSpecializationType(
+                hasDeclaration(classTemplateDecl(has(cxxRecordDecl(
+                    has(varDecl(hasName("mem")).bind("templMem")))))))))),
+            memberHasSameNameAsBoundNode("templMem"))));
+  }
+  {
+    auto Code = R"cpp(
+template <typename T>
+struct S {
+  bool operator==(int) const { return true; }
+};
+
+template <typename T>
+void func(T t) {
+  S<T> s;
+  s.operator==(1);
+}
+)cpp";
+
+    EXPECT_TRUE(matches(
+        Code, cxxDependentScopeMemberExpr(hasMemberName("operator=="))));
+  }
+
+  // other named decl:
+  {
+    auto Code = "template <typename T> struct S{ static int mem; }; struct "
+                "mem{}; template "
+                "<typename T> void x() { S<T> s; s.mem; }";
+
+    EXPECT_TRUE(matches(
+        Code,
+        translationUnitDecl(has(cxxRecordDecl(hasName("mem"))),
+                            hasDescendant(cxxDependentScopeMemberExpr()))));
+
+    EXPECT_FALSE(matches(
+        Code,
+        translationUnitDecl(has(cxxRecordDecl(hasName("mem")).bind("templMem")),
+                            hasDescendant(cxxDependentScopeMemberExpr(
+                                memberHasSameNameAsBoundNode("templMem"))))));
+  }
+}
+
 TEST(ASTMatchersTest, ArgumentCountIs_CXXUnresolvedConstructExpr) {
   const auto *Code =
       "template <typename T> struct S{}; template <typename T> void "
       "x() { auto s = S<T>(); }";
 
   EXPECT_TRUE(matches(Code, cxxUnresolvedConstructExpr(argumentCountIs(0))));
   EXPECT_TRUE(notMatches(Code, cxxUnresolvedConstructExpr(argumentCountIs(1))));
 }