Add option to restrict check to POD types

Author: SimplyDanny

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

@@ -26,6 +26,9 @@ static const char *IgnoreSingleElementAggregatesName =
     "IgnoreSingleElementAggregates";
 static const bool IgnoreSingleElementAggregatesDefault = true;
 
+static const char *RestrictToPODTypesName = "RestrictToPODTypes";
+static const bool RestrictToPODTypesDefault = false;
+
 static std::vector<Stmt *>
 getUndesignatedComponents(const InitListExpr *SyntacticInitList) {
   std::vector<Stmt *> Result;
@@ -37,13 +40,16 @@ getUndesignatedComponents(const InitListExpr *SyntacticInitList) {
 
 UseDesignatedInitializersCheck::UseDesignatedInitializersCheck(
     StringRef Name, ClangTidyContext *Context)
-    : ClangTidyCheck(Name, Context),
-      IgnoreSingleElementAggregates(
-          Options.get(IgnoreSingleElementAggregatesName,
-                      IgnoreSingleElementAggregatesDefault)) {}
+    : ClangTidyCheck(Name, Context), IgnoreSingleElementAggregates(Options.get(
+                                         IgnoreSingleElementAggregatesName,
+                                         IgnoreSingleElementAggregatesDefault)),
+      RestrictToPODTypes(
+          Options.get(RestrictToPODTypesName, RestrictToPODTypesDefault)) {}
 
 AST_MATCHER(CXXRecordDecl, isAggregate) { return Node.isAggregate(); }
 
+AST_MATCHER(CXXRecordDecl, isPOD) { return Node.isPOD(); }
+
 AST_MATCHER(InitListExpr, isFullyDesignated) {
   return getUndesignatedComponents(&Node).empty();
 }
@@ -65,7 +71,8 @@ AST_MATCHER(FieldDecl, isAnonymousDecl) {
 void UseDesignatedInitializersCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(
       initListExpr(
-          hasType(cxxRecordDecl(isAggregate(), unless(hasBaseWithFields()),
+          hasType(cxxRecordDecl(RestrictToPODTypes ? isPOD() : isAggregate(),
+                                unless(hasBaseWithFields()),
                                 unless(has(fieldDecl(isAnonymousDecl()))))
                       .bind("type")),
           unless(IgnoreSingleElementAggregates ? hasSingleElement()
@@ -98,6 +105,7 @@ void UseDesignatedInitializersCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, IgnoreSingleElementAggregatesName,
                 IgnoreSingleElementAggregates);
+  Options.store(Opts, RestrictToPODTypesName, RestrictToPODTypes);
 }
 
 } // namespace clang::tidy::modernize

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

@@ -32,6 +32,7 @@ class UseDesignatedInitializersCheck : public ClangTidyCheck {
 
 private:
   bool IgnoreSingleElementAggregates;
+  bool RestrictToPODTypes;
 };
 
 } // namespace clang::tidy::modernize

clang-tools-extra/docs/clang-tidy/checks/modernize/use-designated-initializers.rst

@@ -46,3 +46,9 @@ Options
 
     The value `false` specifies that even initializers for aggregate types
     with only a single element should be checked. The default value is `true`.
+
+.. option:: RestrictToPODTypes
+
+    The value `true` specifies that only Plain Old Data (POD) types shall be
+    checked. This makes the check applicable to even older C++ standards.
+    The default value is `false`.

clang-tools-extra/test/clang-tidy/checkers/modernize/use-designated-initializers.cpp

@@ -2,6 +2,9 @@
 // RUN: %check_clang_tidy -check-suffixes=,SINGLE-ELEMENT -std=c++17 %s modernize-use-designated-initializers %t \
 // RUN:     -- -config="{CheckOptions: [{key: modernize-use-designated-initializers.IgnoreSingleElementAggregates, value: false}]}" \
 // RUN:     --
+// RUN: %check_clang_tidy -check-suffixes=POD -std=c++17 %s modernize-use-designated-initializers %t \
+// RUN:     -- -config="{CheckOptions: [{key: modernize-use-designated-initializers.RestrictToPODTypes, value: true}]}" \
+// RUN:     --
 
 struct S1 {};
 
@@ -16,14 +19,17 @@ S2 s21{.i=1, .j =2};
 
 S2 s22 = {1, 2};
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use designated initializer list [modernize-use-designated-initializers]
+// CHECK-MESSAGES-POD: :[[@LINE-2]]:10: warning: use designated initializer list [modernize-use-designated-initializers]
 
 S2 s23{1};
 // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: use designated initializer list [modernize-use-designated-initializers]
+// CHECK-MESSAGES-POD: :[[@LINE-2]]:7: warning: use designated initializer list [modernize-use-designated-initializers]
 
 S2 s24{.i = 1};
 
 S2 s25 = {.i=1, 2};
 // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: use designated init expression [modernize-use-designated-initializers]
+// CHECK-MESSAGES-POD: :[[@LINE-2]]:17: warning: use designated init expression [modernize-use-designated-initializers]
 
 class S3 {
   public:
@@ -34,10 +40,14 @@ class S3 {
 S3 s31 = {.s2 = 1, 2, 3.1};
 // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use designated init expression [modernize-use-designated-initializers]
 // CHECK-MESSAGES: :[[@LINE-2]]:23: warning: use designated init expression [modernize-use-designated-initializers]
+// CHECK-MESSAGES-POD: :[[@LINE-3]]:20: warning: use designated init expression [modernize-use-designated-initializers]
+// CHECK-MESSAGES-POD: :[[@LINE-4]]:23: warning: use designated init expression [modernize-use-designated-initializers]
 
 S3 s32 = {{.i = 1, 2}};
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use designated initializer list [modernize-use-designated-initializers]
 // CHECK-MESSAGES: :[[@LINE-2]]:20: warning: use designated init expression [modernize-use-designated-initializers]
+// CHECK-MESSAGES-POD: :[[@LINE-3]]:10: warning: use designated initializer list [modernize-use-designated-initializers]
+// CHECK-MESSAGES-POD: :[[@LINE-4]]:20: warning: use designated init expression [modernize-use-designated-initializers]
 
 struct S4 {
     double d;
@@ -81,3 +91,11 @@ S7 s71 {1};
 struct S8: S7 { int i; };
 
 S8 s81{1, 2};
+
+struct S9 {
+    int i, j;
+    S9 &operator=(S9);
+};
+
+S9 s91{1, 2};
+// CHECK-MESSAGES: :[[@LINE-1]]:7: warning: use designated initializer list [modernize-use-designated-initializers]