[clang] [clang][ASTMatcher] Add matchers for CXXFoldExpr (PR #71245)

[Julian Schmidt via cfe-commits]

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@@ -4532,6 +4563,139 @@ AST_POLYMORPHIC_MATCHER_P2(hasArgument,
   return InnerMatcher.matches(*Arg->IgnoreParenImpCasts(), Finder, Builder);
 }
 
+/// 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
+/// \code
+///   template <typename... Args>
+///   auto sum(Args... args) {
+///       return (0 + ... + args);
+///   }
+///
+///   template <typename... Args>
+///   auto multiply(Args... args) {
+///       return (args * ... * 1);
+///   }
+/// \endcode
+AST_MATCHER_P(CXXFoldExpr, hasFoldInit, ast_matchers::internal::Matcher<Expr>,
+              InnerMacher) {
+  const auto *const Init = Node.getInit();
+  return Init && InnerMacher.matches(*Init, Finder, Builder);
+}
+
+/// Matches the operand that contains the parameter pack.
+///
+/// Example matches `(0 + ... + args)`
+///     (matcher = cxxFoldExpr(hasPattern(expr())))
+///   with hasPattern(...)
+///     matching `args`
+/// \code
+///   template <typename... Args>
+///   auto sum(Args... args) {
+///       return (0 + ... + args);
+///   }
+///
+///   template <typename... Args>
+///   auto multiply(Args... args) {
+///       return (args * ... * 1);
+///   }
+/// \endcode
+AST_MATCHER_P(CXXFoldExpr, hasPattern, ast_matchers::internal::Matcher<Expr>,
+              InnerMacher) {
+  return InnerMacher.matches(*Node.getPattern(), Finder, Builder);
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5chmidti wrote:

done

https://github.com/llvm/llvm-project/pull/71245