[ASTMatchers] Add argumentCountAtLeast narrowing matcher

[mikecrowe]

Summary

This will be used by the modernize-use-std-print clang-tidy check and
related checks later.

[mikecrowe]

clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

1671

I'm not sure if this is the best way to trigger testing of the ignoring default argument path in the implementation of argumentCountAtLeast, but it does seem to work. I added explicit TK_AsIs to the tests above to make it clear that they are not testing that path.

[PiotrZSL]

LGTM, Personally probably I wouldn't extract this to this level, and I would leave it private to a check, but it's fine.

[PiotrZSL]

NOTE: Registry.cpp were not changed, I will add it there during commit if all tests locally pass. If tests fail, I will just add this matcher as private in clang-tidy check.

[PiotrZSL]

Rebase + Added change to Registry.cpp

clang/docs/LibASTMatchersReference.html

try {
     // ...
   } catch (...) {
     // ...
   }
 cxxCatchStmt(isCatchAll()) matches catch(...) but not catch(int).
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXConstructExpr.html">CXXConstructExpr</a>&gt;</td><td class="name" onclick="toggle('argumentCountAtLeast1')"><a name="argumentCountAtLeast1Anchor">argumentCountAtLeast</a></td><td>unsigned N</td></tr>
+<tr><td colspan="4" class="doc" id="argumentCountAtLeast1"><pre>Checks that a call expression or a constructor call expression has
+at least the specified number of arguments (including absent default arguments).
+
+Example matches f(0, 0) and g(0, 0, 0) (matcher = callExpr(argumentCountAtLeast(2)))
+  void f(int x, int y);
+  void g(int x, int y, int z);
+  f(0, 0);
+  g(0, 0, 0);
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXConstructExpr.html">CXXConstructExpr</a>&gt;</td><td class="name" onclick="toggle('argumentCountIs1')"><a name="argumentCountIs1Anchor">argumentCountIs</a></td><td>unsigned N</td></tr>
 <tr><td colspan="4" class="doc" id="argumentCountIs1"><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>

 
 Example 2: matches s1 &lt; s2
            (matcher = cxxOperatorCallExpr(isComparisonOperator()))
   struct S { bool operator&lt;(const S&amp; other); };
   void x(S s1, S s2) { bool b1 = s1 &lt; s2; }
 </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('argumentCountAtLeast2')"><a name="argumentCountAtLeast2Anchor">argumentCountAtLeast</a></td><td>unsigned N</td></tr>
+<tr><td colspan="4" class="doc" id="argumentCountAtLeast2"><pre>Checks that a call expression or a constructor call expression has
+at least the specified number of arguments (including absent default arguments).
+
+Example matches f(0, 0) and g(0, 0, 0) (matcher = callExpr(argumentCountAtLeast(2)))
+  void f(int x, int y);
+  void g(int x, int y, int z);
+  f(0, 0);
+  g(0, 0, 0);
+</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('argumentCountAtLeast0')"><a name="argumentCountAtLeast0Anchor">argumentCountAtLeast</a></td><td>unsigned N</td></tr>
+<tr><td colspan="4" class="doc" id="argumentCountAtLeast0"><pre>Checks that a call expression or a constructor call expression has
+at least the specified number of arguments (including absent default arguments).
+
+Example matches f(0, 0) and g(0, 0, 0) (matcher = callExpr(argumentCountAtLeast(2)))
+  void f(int x, int y);
+  void g(int x, int y, int z);
+  f(0, 0);
+  g(0, 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('argumentCountAtLeast3')"><a name="argumentCountAtLeast3Anchor">argumentCountAtLeast</a></td><td>unsigned N</td></tr>
+<tr><td colspan="4" class="doc" id="argumentCountAtLeast3"><pre>Checks that a call expression or a constructor call expression has
+at least the specified number of arguments (including absent default arguments).
+
+Example matches f(0, 0) and g(0, 0, 0) (matcher = callExpr(argumentCountAtLeast(2)))
+  void f(int x, int y);
+  void g(int x, int y, int z);
+  f(0, 0);
+  g(0, 0, 0);
+</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('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>

clang/include/clang/ASTMatchers/ASTMatchers.h

AST_POLYMORPHIC_MATCHER_P(argumentCountIs,
   while (NumArgs) {
     if (!isa<CXXDefaultArgExpr>(Node.getArg(NumArgs - 1)))
       break;
     --NumArgs;
   }
   return NumArgs == N;
 }
 
+/// Checks that a call expression or a constructor call expression has at least
+/// the specified number of arguments (including absent default arguments).
+///
+/// Example matches f(0, 0) and g(0, 0, 0)
+/// (matcher = callExpr(argumentCountAtLeast(2)))
+/// \code
+///   void f(int x, int y);
+///   void g(int x, int y, int z);
+///   f(0, 0);
+///   g(0, 0, 0);
+/// \endcode
+AST_POLYMORPHIC_MATCHER_P(argumentCountAtLeast,
+                          AST_POLYMORPHIC_SUPPORTED_TYPES(
+                              CallExpr, CXXConstructExpr,
+                              CXXUnresolvedConstructExpr, ObjCMessageExpr),
+                          unsigned, N) {
+  unsigned NumArgs = Node.getNumArgs();
+  if (!Finder->isTraversalIgnoringImplicitNodes())
+    return NumArgs >= N;
+  while (NumArgs) {
+    if (!isa<CXXDefaultArgExpr>(Node.getArg(NumArgs - 1)))
+      break;
+    --NumArgs;
+  }
+  return NumArgs >= N;
+}
+
 /// 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())))
 /// \code
 ///   void x(int) { int y; x(y); }
 /// \endcode

clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

EXPECT_TRUE(
       notMatches("template<bool b> struct S { explicit(b) operator int(); };",
                  cxxConversionDecl(isExplicit())));
   EXPECT_TRUE(matches("struct S { explicit(true) operator int(); };",
                       cxxConversionDecl(isExplicit())));
   EXPECT_TRUE(notMatches("struct S { explicit(false) operator int(); };",
                          cxxConversionDecl(isExplicit())));
 }
 
+TEST_P(ASTMatchersTest, ArgumentCountAtLeast_CallExpr) {
+  StatementMatcher Call2PlusArgs = callExpr(argumentCountAtLeast(2));
+
+  EXPECT_TRUE(notMatches("void x(void) { x(); }", Call2PlusArgs));
+  EXPECT_TRUE(notMatches("void x(int) { x(0); }", Call2PlusArgs));
+  EXPECT_TRUE(matches("void x(int, int) { x(0, 0); }", Call2PlusArgs));
+  EXPECT_TRUE(matches("void x(int, int, int) { x(0, 0, 0); }", Call2PlusArgs));
+
+  if (!GetParam().isCXX()) {
+    return;
+  }
+
+  EXPECT_TRUE(
+      notMatches("void x(int = 1) { x(); }", traverse(TK_AsIs, Call2PlusArgs)));
+  EXPECT_TRUE(matches("void x(int, int = 1) { x(0); }",
+                      traverse(TK_AsIs, Call2PlusArgs)));
+  EXPECT_TRUE(matches("void x(int, int = 1, int = 1) { x(0); }",
+                      traverse(TK_AsIs, Call2PlusArgs)));
+  EXPECT_TRUE(matches("void x(int, int, int = 1) { x(0, 0); }",
+                      traverse(TK_AsIs, Call2PlusArgs)));
+  EXPECT_TRUE(matches("void x(int, int, int, int = 1) { x(0, 0, 0); }",
+                      traverse(TK_AsIs, Call2PlusArgs)));
+
+  EXPECT_TRUE(
+      notMatches("void x(int = 1) { x(); }",
+                 traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+  EXPECT_TRUE(
+      notMatches("void x(int, int = 1) { x(0); }",
+                 traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+  EXPECT_TRUE(
+      notMatches("void x(int, int = 1, int = 1) { x(0); }",
+                 traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+  EXPECT_TRUE(matches("void x(int, int, int = 1) { x(0, 0); }",
+                      traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+  EXPECT_TRUE(matches("void x(int, int, int, int = 1) { x(0, 0, 0); }",
+                      traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+}
+
+TEST_P(ASTMatchersTest, ArgumentCountAtLeast_CallExpr_CXX) {
+  if (!GetParam().isCXX()) {
+    return;
+  }
+
+  StatementMatcher Call2PlusArgs = callExpr(argumentCountAtLeast(2));
+  EXPECT_TRUE(notMatches("class X { void x() { x(); } };", Call2PlusArgs));
+  EXPECT_TRUE(notMatches("class X { void x(int) { x(0); } };", Call2PlusArgs));
+  EXPECT_TRUE(
+      matches("class X { void x(int, int) { x(0, 0); } };", Call2PlusArgs));
+  EXPECT_TRUE(matches("class X { void x(int, int, int) { x(0, 0, 0); } };",
+                      Call2PlusArgs));
+
+  EXPECT_TRUE(notMatches("class X { void x(int = 1) { x(0); } };",
+                         traverse(TK_AsIs, Call2PlusArgs)));
+  EXPECT_TRUE(matches("class X { void x(int, int = 1) { x(0); } };",
+                      traverse(TK_AsIs, Call2PlusArgs)));
+  EXPECT_TRUE(matches("class X { void x(int, int = 1, int = 1) { x(0); } };",
+                      traverse(TK_AsIs, Call2PlusArgs)));
+  EXPECT_TRUE(matches("class X { void x(int, int, int = 1) { x(0, 0); } };",
+                      traverse(TK_AsIs, Call2PlusArgs)));
+  EXPECT_TRUE(
+      matches("class X { void x(int, int, int, int = 1) { x(0, 0, 0); } };",
+              traverse(TK_AsIs, Call2PlusArgs)));
+
+  EXPECT_TRUE(
+      notMatches("class X { void x(int = 1) { x(0); } };",
+                 traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+  EXPECT_TRUE(
+      notMatches("class X { void x(int, int = 1) { x(0); } };",
+                 traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+  EXPECT_TRUE(
+      notMatches("class X { void x(int, int = 1, int = 1) { x(0); } };",
+                 traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+  EXPECT_TRUE(matches("class X { void x(int, int, int = 1) { x(0, 0); } };",
+                      traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+  EXPECT_TRUE(
+      matches("class X { void x(int, int, int, int = 1) { x(0, 0, 0); } };",
+              traverse(TK_IgnoreUnlessSpelledInSource, Call2PlusArgs)));
+
+  EXPECT_TRUE(
+      notMatches("class X { static void x() { x(); } };", Call2PlusArgs));
+  EXPECT_TRUE(
+      notMatches("class X { static void x(int) { x(0); } };", Call2PlusArgs));
+  EXPECT_TRUE(matches("class X { static void x(int, int) { x(0, 0); } };",
+                      Call2PlusArgs));
+  EXPECT_TRUE(
+      matches("class X { static void x(int, int, int) { x(0, 0, 0); } };",
+              Call2PlusArgs));
+}
+
 TEST_P(ASTMatchersTest, ArgumentCountIs_CallExpr) {
   StatementMatcher Call1Arg = callExpr(argumentCountIs(1));
 
   EXPECT_TRUE(matches("void x(int) { x(0); }", Call1Arg));
   EXPECT_TRUE(notMatches("void x(int, int) { x(0, 0); }", Call1Arg));
 }
 
 TEST_P(ASTMatchersTest, ArgumentCountIs_CallExpr_CXX) {