[PATCH] D24892: [clang-tidy] Add option "LiteralInitializers" to cppcoreguidelines-pro-type-member-init

[Matthias Gehre via cfe-commits]

mgehre created this revision.
mgehre added reviewers: alexfh, aaron.ballman, hokein.
mgehre added a subscriber: cfe-commits.
Herald added a subscriber: nemanjai.

Adds the option "LiteralInitializers" to
cppcoreguidelines-pro-type-member-init.
If set to non-zero, the check will provide fix-its with literal
initializers (``int i = 0;``) instead of curly braces (``int i{};``).

If find that more readable. Of course, this is purely a question of style,
thus the option is disabled by default.

https://reviews.llvm.org/D24892

Files:
  clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
  clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.h
  docs/clang-tidy/checks/cppcoreguidelines-pro-type-member-init.rst
  test/clang-tidy/cppcoreguidelines-pro-type-member-init-literal-initializers.cpp

Index: test/clang-tidy/cppcoreguidelines-pro-type-member-init-literal-initializers.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/cppcoreguidelines-pro-type-member-init-literal-initializers.cpp
@@ -0,0 +1,15 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-pro-type-member-init %t -- -config="{CheckOptions: [{key: "cppcoreguidelines-pro-type-member-init.LiteralInitializers", value: 1}]}" -- -std=c++11
+
+struct S {
+  bool b;
+  // CHECK-FIXES: bool b = false;
+  int i;
+  // CHECK-FIXES: int i = 0;
+  float f;
+  // CHECK-FIXES: float f = 0.0;
+  int* ptr;
+  // CHECK-FIXES: int* ptr = nullptr;
+  S() {};
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these fields:
+};
+
Index: docs/clang-tidy/checks/cppcoreguidelines-pro-type-member-init.rst
===================================================================
--- docs/clang-tidy/checks/cppcoreguidelines-pro-type-member-init.rst
+++ docs/clang-tidy/checks/cppcoreguidelines-pro-type-member-init.rst
@@ -33,6 +33,10 @@
    zero-initialized during construction. For performance critical code, it may
    be important to not initialize fixed-size array members.  Default is `0`.
 
+.. option:: LiteralInitializers
+   If set to non-zero, the check will provide fix-its with literal initializers
+   (``int i = 0;``) instead of curly braces (``int i{};``).
+
 This rule is part of the "Type safety" profile of the C++ Core
 Guidelines, corresponding to rule Type.6. See
 https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-memberinit.
Index: clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.h
===================================================================
--- clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.h
+++ clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.h
@@ -63,6 +63,9 @@
 
   // Whether arrays need to be initialized or not. Default is false.
   bool IgnoreArrays;
+  // Whether fix-its for initializers of fundamental type use literals. Only
+  // effective in C++11 mode. Default is false.
+  bool LiteralInitializers;
 };
 
 } // namespace cppcoreguidelines
Index: clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
===================================================================
--- clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
+++ clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
@@ -251,7 +251,8 @@
 ProTypeMemberInitCheck::ProTypeMemberInitCheck(StringRef Name,
                                                ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IgnoreArrays(Options.get("IgnoreArrays", false)) {}
+      IgnoreArrays(Options.get("IgnoreArrays", false)),
+      LiteralInitializers(Options.get("LiteralInitializers", false)) {}
 
 void ProTypeMemberInitCheck::registerMatchers(MatchFinder *Finder) {
   if (!getLangOpts().CPlusPlus)
@@ -296,6 +297,7 @@
 
 void ProTypeMemberInitCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "IgnoreArrays", IgnoreArrays);
+  Options.store(Opts, "LiteralInitializers", LiteralInitializers);
 }
 
 void ProTypeMemberInitCheck::checkMissingMemberInitializer(
@@ -366,9 +368,21 @@
   // Use in-class initialization if possible.
   if (Context.getLangOpts().CPlusPlus11) {
     for (const FieldDecl *Field : FieldsToFix) {
+      QualType type = Field->getType();
+      const char *Initializer = "{}";
+      if (LiteralInitializers) {
+        if (type->isBooleanType())
+          Initializer = " = false";
+        else if (type->isIntegerType())
+          Initializer = " = 0";
+        else if (type->isFloatingType())
+          Initializer = " = 0.0";
+        else if (type->isPointerType())
+          Initializer = " = nullptr";
+      }
       Diag << FixItHint::CreateInsertion(
           getLocationForEndOfToken(Context, Field->getSourceRange().getEnd()),
-          "{}");
+          Initializer);
     }
   } else {
     // Otherwise, rewrite the constructor's initializer list.


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