[ASTMatchers] Overload isConstexpr for ifStmts

[xazax.hun]

Summary

The HTML is the result of running the dump_ast_matchers.py script. There are more changes than I expected, looks like some link disappeared. I do not know if that is intentional.

[alexfh]

docs/LibASTMatchersReference.html

179

The changes don't look nice. It looks like either dump_ast_matchers.py can't access network on your machine. Can this be the case? The URLs (e.g. http://clang.llvm.org/doxygen/classclang_1_1CXXMethodDecl.html) seem to work for me.

[alexfh]

docs/LibASTMatchersReference.html

179

Just checked that the script still works fine.

[aaron.ballman]

Aside from the issue @alexfh raised, this LGTM.

[xazax.hun]

• Rerun script

[xazax.hun]

docs/LibASTMatchersReference.html

179

Thanks! I think this is the result of my or the doxygen host's network being unreliable. I was unable to generate a good documentation after the first few trials, the links for a few (but not all) node were always missing. I ended up pruning those changes from the diff manually.

[alexfh]

LG

docs/LibASTMatchersReference.html

 Example matches Foo::~Foo()
   class Foo {
    public:
     virtual ~Foo();
   };
 </pre></td></tr>
 
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('cxxMethodDecl0')"><a name="cxxMethodDecl0Anchor">cxxMethodDecl</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1CXXMethodDecl.html">CXXMethodDecl</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="cxxMethodDecl0"><pre>Matches method declarations.
 
 Example matches y
   class X { void y(); };
 </pre></td></tr>
 
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('cxxRecordDecl0')"><a name="cxxRecordDecl0Anchor">cxxRecordDecl</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1CXXRecordDecl.html">CXXRecordDecl</a>&gt;...</td></tr>

 
 Example matches Y (matcher = functionDecl(hasTrailingReturn()))
 int X() {}
 auto Y() -&gt; int {}
 </pre></td></tr>
 
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html">FunctionDecl</a>&gt;</td><td class="name" onclick="toggle('isConstexpr1')"><a name="isConstexpr1Anchor">isConstexpr</a></td><td></td></tr>
-<tr><td colspan="4" class="doc" id="isConstexpr1"><pre>Matches constexpr variable and function declarations.
+<tr><td colspan="4" class="doc" id="isConstexpr1"><pre>Matches constexpr variable and function declarations,
+       and if constexpr.
 
 Given:
   constexpr int foo = 42;
   constexpr int bar();
+  void baz() { if constexpr(1 &gt; 0) {} }
 varDecl(isConstexpr())
   matches the declaration of foo.
 functionDecl(isConstexpr())
   matches the declaration of bar.
+ifStmt(isConstexpr())
+  matches the if statement in baz.
 </pre></td></tr>
 
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html">FunctionDecl</a>&gt;</td><td class="name" onclick="toggle('isDefaulted0')"><a name="isDefaulted0Anchor">isDefaulted</a></td><td></td></tr>
 <tr><td colspan="4" class="doc" id="isDefaulted0"><pre>Matches defaulted function declarations.
 
 Given:
   class A { ~A(); };
functionDecl(parameterCountIs(2))
   matches g and h
 functionProtoType(parameterCountIs(2))
   matches g and h
 functionProtoType(parameterCountIs(3))
   matches k
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1IfStmt.html">IfStmt</a>&gt;</td><td class="name" onclick="toggle('isConstexpr2')"><a name="isConstexpr2Anchor">isConstexpr</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isConstexpr2"><pre>Matches constexpr variable and function declarations,
+       and if constexpr.
+
+Given:
+  constexpr int foo = 42;
+  constexpr int bar();
+  void baz() { if constexpr(1 &gt; 0) {} }
+varDecl(isConstexpr())
+  matches the declaration of foo.
+functionDecl(isConstexpr())
+  matches the declaration of bar.
+ifStmt(isConstexpr())
+  matches the if statement in baz.
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1IntegerLiteral.html">IntegerLiteral</a>&gt;</td><td class="name" onclick="toggle('equals6')"><a name="equals6Anchor">equals</a></td><td>bool Value</td></tr>
 <tr><td colspan="4" class="doc" id="equals6"><pre></pre></td></tr>
 
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1IntegerLiteral.html">IntegerLiteral</a>&gt;</td><td class="name" onclick="toggle('equals0')"><a name="equals0Anchor">equals</a></td><td>const ValueT  Value</td></tr>
 <tr><td colspan="4" class="doc" id="equals0"><pre>Matches literals that are equal to the given value of type ValueT.
 
 Given
void f() {
   static int y;
   thread_local int z;
 }
 int a;
 </pre></td></tr>
 
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1VarDecl.html">VarDecl</a>&gt;</td><td class="name" onclick="toggle('isConstexpr0')"><a name="isConstexpr0Anchor">isConstexpr</a></td><td></td></tr>
-<tr><td colspan="4" class="doc" id="isConstexpr0"><pre>Matches constexpr variable and function declarations.
+<tr><td colspan="4" class="doc" id="isConstexpr0"><pre>Matches constexpr variable and function declarations,
+       and if constexpr.
 
 Given:
   constexpr int foo = 42;
   constexpr int bar();
+  void baz() { if constexpr(1 &gt; 0) {} }
 varDecl(isConstexpr())
   matches the declaration of foo.
 functionDecl(isConstexpr())
   matches the declaration of bar.
+ifStmt(isConstexpr())
+  matches the if statement in baz.
 </pre></td></tr>
 
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1VarDecl.html">VarDecl</a>&gt;</td><td class="name" onclick="toggle('isDefinition1')"><a name="isDefinition1Anchor">isDefinition</a></td><td></td></tr>
 <tr><td colspan="4" class="doc" id="isDefinition1"><pre>Matches if a declaration has a body attached.
 
 Example matches A, va, fa
   class A {};

include/clang/ASTMatchers/ASTMatchers.h

AST_POLYMORPHIC_MATCHER(isNoThrow,
 
   // Assume the best for any unresolved exception specification.
   if (isUnresolvedExceptionSpec(FnTy->getExceptionSpecType()))
     return true;
 
   return FnTy->isNothrow();
 }
 
-/// \brief Matches constexpr variable and function declarations.
+/// \brief Matches constexpr variable and function declarations,
+///        and if constexpr.
 ///
 /// Given:
 /// \code
 ///   constexpr int foo = 42;
 ///   constexpr int bar();
+///   void baz() { if constexpr(1 > 0) {} }
 /// \endcode
 /// varDecl(isConstexpr())
 ///   matches the declaration of foo.
 /// functionDecl(isConstexpr())
 ///   matches the declaration of bar.
+/// ifStmt(isConstexpr())
+///   matches the if statement in baz.
 AST_POLYMORPHIC_MATCHER(isConstexpr,
                         AST_POLYMORPHIC_SUPPORTED_TYPES(VarDecl,
-                                                        FunctionDecl)) {
+                                                        FunctionDecl,
+                                                        IfStmt)) {
   return Node.isConstexpr();
 }
 
 /// \brief Matches the condition expression of an if statement, for loop,
 /// switch statement or conditional operator.
 ///
 /// Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
 /// \code

unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

TEST(IsNoThrow, MatchesNoThrowFunctionDeclarations) {
   EXPECT_TRUE(matches("void f() noexcept;", functionProtoType(isNoThrow())));
 }
 
 TEST(isConstexpr, MatchesConstexprDeclarations) {
   EXPECT_TRUE(matches("constexpr int foo = 42;",
                       varDecl(hasName("foo"), isConstexpr())));
   EXPECT_TRUE(matches("constexpr int bar();",
                       functionDecl(hasName("bar"), isConstexpr())));
+  EXPECT_TRUE(matchesConditionally("void baz() { if constexpr(1 > 0) {} }",
+                                   ifStmt(isConstexpr()), true, "-std=c++17"));
+  EXPECT_TRUE(matchesConditionally("void baz() { if (1 > 0) {} }",
+                                   ifStmt(isConstexpr()), false, "-std=c++17"));
 }
 
 TEST(TemplateArgumentCountIs, Matches) {
   EXPECT_TRUE(
     matches("template<typename T> struct C {}; C<int> c;",
             classTemplateSpecializationDecl(templateArgumentCountIs(1))));
   EXPECT_TRUE(
     notMatches("template<typename T> struct C {}; C<int> c;",