Use duck-typing to get pair type

Author: flovent

clang-tools-extra/clang-tidy/modernize/UseStructuredBindingCheck.cpp

@@ -8,14 +8,12 @@
 
 #include "UseStructuredBindingCheck.h"
 #include "../utils/DeclRefExprUtils.h"
-#include "../utils/OptionsUtils.h"
 #include "clang/Lex/Lexer.h"
 
 using namespace clang::ast_matchers;
 
 namespace clang::tidy::modernize {
 
-static constexpr const char *DefaultPairTypes = "std::pair";
 static constexpr llvm::StringLiteral PairDeclName = "PairVarD";
 static constexpr llvm::StringLiteral PairVarTypeName = "PairVarType";
 static constexpr llvm::StringLiteral FirstVarDeclName = "FirstVarDecl";
@@ -178,16 +176,15 @@ AST_MATCHER_P(Expr, ignoringCopyCtorAndImplicitCast,
   return InnerMatcher.matches(*Node.IgnoreImpCasts(), Finder, Builder);
 }
 
-} // namespace
-
-UseStructuredBindingCheck::UseStructuredBindingCheck(StringRef Name,
-                                                     ClangTidyContext *Context)
-    : ClangTidyCheck(Name, Context),
-      PairTypes(utils::options::parseStringList(
-          Options.get("PairTypes", DefaultPairTypes))) {
-  ;
+AST_MATCHER(CXXRecordDecl, isPairType) {
+  return llvm::all_of(Node.fields(), [](const FieldDecl *FD) {
+    return FD->getAccess() == AS_public &&
+           (FD->getName() == "first" || FD->getName() == "second");
+  });
 }
 
+} // namespace
+
 static auto getVarInitWithMemberMatcher(
     StringRef PairName, StringRef MemberName, StringRef TypeName,
     StringRef BindingName,
@@ -204,10 +201,9 @@ static auto getVarInitWithMemberMatcher(
 }
 
 void UseStructuredBindingCheck::registerMatchers(MatchFinder *Finder) {
-  auto PairType =
-      qualType(unless(isVolatileQualified()),
-               hasUnqualifiedDesugaredType(recordType(
-                   hasDeclaration(cxxRecordDecl(hasAnyName(PairTypes))))));
+  auto PairType = qualType(unless(isVolatileQualified()),
+                           hasUnqualifiedDesugaredType(recordType(
+                               hasDeclaration(cxxRecordDecl(isPairType())))));
 
   auto UnlessShouldBeIgnored =
       unless(anyOf(hasAnySpecifiersShouldBeIgnored(), isInMarco()));

clang-tools-extra/clang-tidy/modernize/UseStructuredBindingCheck.h

@@ -20,15 +20,13 @@ namespace clang::tidy::modernize {
 /// http://clang.llvm.org/extra/clang-tidy/checks/modernize/use-structured-binding.html
 class UseStructuredBindingCheck : public ClangTidyCheck {
 public:
-  UseStructuredBindingCheck(StringRef Name, ClangTidyContext *Context);
+  UseStructuredBindingCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
     return LangOpts.CPlusPlus17;
   }
-
-private:
-  const std::vector<StringRef> PairTypes;
 };
 
 } // namespace clang::tidy::modernize

clang-tools-extra/docs/clang-tidy/checks/modernize/use-structured-binding.rst

@@ -84,12 +84,3 @@ and:
   if (results.second) {
       handle_inserted(results.first);
   }
-
-Options
--------
-
-.. option:: PairTypes
-
-   A semicolon-separated list of type names to be treated as pair-like for
-   structured binding suggestions. Example: `MyPairType;OtherPairType`. 
-   Default is `std::pair`.

clang-tools-extra/test/clang-tidy/checkers/modernize/use-structured-binding-custom.cpp

@@ -388,3 +388,46 @@ void stdTieNotWarn() {
     x = 1;
   };
 }
+
+struct otherPair {
+  int first;
+  int second;
+};
+
+void OtherPairTest() {
+  {
+    auto P = otherPair();
+    // CHECK-MESSAGES-ALL: :[[@LINE-1]]:5: warning: use a structured binding to decompose a pair [modernize-use-structured-binding]
+    // CHECK-FIXES-ALL: auto [x, y] = otherPair();
+    int x = P.first;
+    int y = P.second;
+  }
+}
+
+struct otherNonPair1 {
+  int first;
+  int second;
+
+private:
+  int third;
+};
+
+struct otherNonPair2 {
+  int first;
+  int second;
+  int third;
+};
+
+void OtherNonPairTest() {
+  {
+    auto P = otherNonPair1();
+    int x = P.first;
+    int y = P.second;
+  }
+
+  {
+    auto P = otherNonPair2();
+    int x = P.first;
+    int y = P.second;
+  }
+}