[clang][ASTMatcher] Add matchers for CXXFoldExpr

Author: 5chmidti

clang/docs/LibASTMatchersReference.html

@@ -1629,6 +1629,17 @@ <h2 id="decl-matchers">Node Matchers</h2>
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('cxxFoldExpr0')"><a name="cxxFoldExpr0Anchor">cxxFoldExpr</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="cxxFoldExpr0"><pre>Matches C++17 fold expressions.
+
+Example matches `(0 + ... + args)`:
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('cxxForRangeStmt0')"><a name="cxxForRangeStmt0Anchor">cxxForRangeStmt</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXForRangeStmt.html">CXXForRangeStmt</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="cxxForRangeStmt0"><pre>Matches range-based for statements.
 
@@ -3430,6 +3441,92 @@ <h2 id="narrowing-matchers">Narrowing Matchers</h2>
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('hasOperator0')"><a name="hasOperator0Anchor">hasOperator</a></td><td>BinaryOperatorKind Op</td></tr>
+<tr><td colspan="4" class="doc" id="hasOperator0"><pre>Matches the operator kind of the fold expression.
+
+Example matches `(0 + ... + args)`
+    (matcher = cxxFoldExpr(hasOperator(BO_Add)))
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ... * 1);
+  }
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('isBinaryFold0')"><a name="isBinaryFold0Anchor">isBinaryFold</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isBinaryFold0"><pre>Matches binary fold expressions, i.e. fold expressions with an initializer.
+
+Example matches `(0 + ... + args)`
+    (matcher = cxxFoldExpr(isBinaryFold()))
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ...);
+  }
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('isLeftFold0')"><a name="isLeftFold0Anchor">isLeftFold</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isLeftFold0"><pre>Matches left-folding fold expressions.
+
+Example matches `(0 + ... + args)`
+    (matcher = cxxFoldExpr(isLeftFold()))
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ... * 1);
+  }
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('isRightFold0')"><a name="isRightFold0Anchor">isRightFold</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isRightFold0"><pre>Matches right-folding fold expressions.
+
+Example matches `(args * ... * 1)`
+    (matcher = cxxFoldExpr(isRightFold()))
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ... * 1);
+  }
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('isUnaryFold0')"><a name="isUnaryFold0Anchor">isUnaryFold</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isUnaryFold0"><pre>Matches unary fold expressions, i.e. fold expressions without an
+initializer.
+
+Example matches `(args * ...)`
+    (matcher = cxxFoldExpr(isUnaryFold()))
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ...);
+  }
+</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.
 
@@ -6885,6 +6982,93 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</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_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
+<tr><td colspan="4" class="doc" id="callee1"><pre>Matches if the call or fold expression's callee expression matches.
+
+Given
+  class Y { void x() { this-&gt;x(); x(); Y y; y.x(); } };
+  void f() { f(); }
+callExpr(callee(expr()))
+  matches this-&gt;x(), x(), y.x(), f()
+with callee(...)
+  matching this-&gt;x, x, y.x, f respectively
+
+Given
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ... * 1);
+  }
+cxxFoldExpr(callee(expr()))
+  matches (args * ... * 1)
+with callee(...)
+  matching *
+
+Note: Callee cannot take the more general internal::Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt;
+because this introduces ambiguous overloads with calls to Callee taking a
+internal::Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;, as the matcher hierarchy is purely
+implemented in terms of implicit casts.
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('hasFoldInit0')"><a name="hasFoldInit0Anchor">hasFoldInit</a></td><td>ast_matchers::Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMacher</td></tr>
+<tr><td colspan="4" class="doc" id="hasFoldInit0"><pre>Matches the operand that does not contain the parameter pack.
+
+Example matches `(0 + ... + args)` and `(args * ... * 1)`
+    (matcher = cxxFoldExpr(hasFoldInit(expr())))
+  with hasFoldInit(...)
+    matching `0` and `1` respectively
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ... * 1);
+  }
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('hasLHS4')"><a name="hasLHS4Anchor">hasLHS</a></td><td>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="hasLHS4"><pre>Matches the left hand side of binary operator expressions.
+
+Example matches a (matcher = binaryOperator(hasLHS()))
+  a || b
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('hasPattern0')"><a name="hasPattern0Anchor">hasPattern</a></td><td>ast_matchers::Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMacher</td></tr>
+<tr><td colspan="4" class="doc" id="hasPattern0"><pre>Matches the operand that contains the parameter pack.
+
+Example matches `(0 + ... + args)`
+    (matcher = cxxFoldExpr(hasPattern(expr())))
+  with hasPattern(...)
+    matching `args`
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ... * 1);
+  }
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXFoldExpr.html">CXXFoldExpr</a>&gt;</td><td class="name" onclick="toggle('hasRHS4')"><a name="hasRHS4Anchor">hasRHS</a></td><td>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="hasRHS4"><pre>Matches the right hand side of binary operator expressions.
+
+Example matches b (matcher = binaryOperator(hasRHS()))
+  a || b
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXForRangeStmt.html">CXXForRangeStmt</a>&gt;</td><td class="name" onclick="toggle('hasBody3')"><a name="hasBody3Anchor">hasBody</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="hasBody3"><pre>Matches a 'for', 'while', 'while' statement or a function or coroutine
 definition that has a given body. Note that in case of functions or
@@ -7436,8 +7620,8 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 </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('callee2')"><a name="callee2Anchor">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="callee2"><pre>Matches 1) if the call expression's callee's declaration matches the
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CallExpr.html">CallExpr</a>&gt;</td><td class="name" onclick="toggle('callee3')"><a name="callee3Anchor">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="callee3"><pre>Matches 1) if the call expression's callee's declaration matches the
 given matcher; or 2) if the Obj-C message expression's callee's method
 declaration matches the given matcher.
 
@@ -7458,7 +7642,7 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 
 
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CallExpr.html">CallExpr</a>&gt;</td><td class="name" onclick="toggle('callee0')"><a name="callee0Anchor">callee</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
-<tr><td colspan="4" class="doc" id="callee0"><pre>Matches if the call expression's callee expression matches.
+<tr><td colspan="4" class="doc" id="callee0"><pre>Matches if the call or fold expression's callee expression matches.
 
 Given
   class Y { void x() { this-&gt;x(); x(); Y y; y.x(); } };
@@ -7468,6 +7652,21 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 with callee(...)
   matching this-&gt;x, x, y.x, f respectively
 
+Given
+  template &lt;typename... Args&gt;
+  auto sum(Args... args) {
+      return (0 + ... + args);
+  }
+
+  template &lt;typename... Args&gt;
+  auto multiply(Args... args) {
+      return (args * ... * 1);
+  }
+cxxFoldExpr(callee(expr()))
+  matches (args * ... * 1)
+with callee(...)
+  matching *
+
 Note: Callee cannot take the more general internal::Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt;
 because this introduces ambiguous overloads with calls to Callee taking a
 internal::Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;, as the matcher hierarchy is purely
@@ -9087,8 +9286,8 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 </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('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 1) if the call expression's callee's declaration matches the
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('callee2')"><a name="callee2Anchor">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="callee2"><pre>Matches 1) if the call expression's callee's declaration matches the
 given matcher; or 2) if the Obj-C message expression's callee's method
 declaration matches the given matcher.
 

clang/docs/ReleaseNotes.rst

@@ -830,6 +830,9 @@ AST Matchers
 - Add ``convertVectorExpr``.
 - Add ``dependentSizedExtVectorType``.
 - Add ``macroQualifiedType``.
+- Add ``CXXFoldExpr`` related matchers: ``cxxFoldExpr``, ``callee``,
+  ``hasInit``, ``hasPattern``, ``isRightFold``, ``isLeftFold``,
+  ``isUnaryFold``, ``isBinaryFold``, ``hasOperator``, ``hasLHS``, ``hasRHS``.
 
 clang-format
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