[PATCH] D42426: [clang-tidy] Handle bitfields in cppcoreguidelines-pro-type-member-init if using C++2a

[Malcolm Parsons via Phabricator via cfe-commits]

malcolm.parsons created this revision.
malcolm.parsons added reviewers: aaron.ballman, alexfh.
Herald added subscribers: cfe-commits, kbarton, xazax.hun, nemanjai, klimek.

C++2a allows bitfields to have default member initializers.
Add support for this to clang-tidy's cppcoreguidelines-pro-type-member-init check.


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D42426

Files:
  clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
  test/clang-tidy/cppcoreguidelines-pro-type-member-init-cxx2a.cpp
  test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp


Index: test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
===================================================================
--- test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
+++ test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
@@ -474,6 +474,7 @@
   PositiveBitfieldMember() {}
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these fields: F
   unsigned F : 5;
+  // CHECK-FIXES-NOT: unsigned F : 5{};
 };
 
 struct NegativeUnnamedBitfieldMember {
Index: test/clang-tidy/cppcoreguidelines-pro-type-member-init-cxx2a.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/cppcoreguidelines-pro-type-member-init-cxx2a.cpp
@@ -0,0 +1,19 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-pro-type-member-init %t -- -- -std=c++2a -fno-delayed-template-parsing
+
+struct PositiveBitfieldMember {
+  PositiveBitfieldMember() {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these fields: F
+  unsigned F : 5;
+  // CHECK-FIXES: unsigned F : 5{};
+};
+
+struct NegativeUnnamedBitfieldMember {
+  NegativeUnnamedBitfieldMember() {}
+  unsigned : 5;
+};
+
+struct NegativeInitializedBitfieldMembers {
+  NegativeInitializedBitfieldMembers() : F(3) { G = 2; }
+  unsigned F : 5;
+  unsigned G : 5;
+};
Index: clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
===================================================================
--- clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
+++ clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
@@ -404,8 +404,9 @@
       return;
     // Don't suggest fixes for enums because we don't know a good default.
     // Don't suggest fixes for bitfields because in-class initialization is not
-    // possible.
-    if (F->getType()->isEnumeralType() || F->isBitField())
+    // possible until C++2a.
+    if (F->getType()->isEnumeralType() ||
+        (!getLangOpts().CPlusPlus2a && F->isBitField()))
       return;
     if (!F->getParent()->isUnion() || UnionsSeen.insert(F->getParent()).second)
       FieldsToFix.insert(F);


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