[clang-tidy] Add modernize-use-equals-delete check

Summary: Fixes PR27872

Reviewers: klimek, hokein, alexfh, aaron.ballman

Subscribers: Prazek, Eugene.Zelenko, danielmarjamaki, cfe-commits, mgorny

Differential Revision: https://reviews.llvm.org/D26138

llvm-svn: 286472

9 files changed, 289 insertions, 2 deletions

diff --git a/clang-tools-extra/clang-tidy/modernize/CMakeLists.txt b/clang-tools-extra/clang-tidy/modernize/CMakeLists.txt
index 57a2b4e31b3..125c6dded25 100644
--- a/clang-tools-extra/clang-tidy/modernize/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/modernize/CMakeLists.txt
@@ -18,6 +18,7 @@ add_clang_library(clangTidyModernizeModule
   UseBoolLiteralsCheck.cpp
   UseDefaultCheck.cpp
   UseEmplaceCheck.cpp
+  UseEqualsDeleteCheck.cpp
   UseNullptrCheck.cpp
   UseOverrideCheck.cpp
   UseUsingCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp b/clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp
index 3fa23daa0ff..de8ed0aa887 100644
--- a/clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp
@@ -24,6 +24,7 @@
 #include "UseBoolLiteralsCheck.h"
 #include "UseDefaultCheck.h"
 #include "UseEmplaceCheck.h"
+#include "UseEqualsDeleteCheck.h"
 #include "UseNullptrCheck.h"
 #include "UseOverrideCheck.h"
 #include "UseUsingCheck.h"
@@ -56,6 +57,8 @@ public:
         "modernize-use-bool-literals");
     CheckFactories.registerCheck<UseDefaultCheck>("modernize-use-default");
     CheckFactories.registerCheck<UseEmplaceCheck>("modernize-use-emplace");
+    CheckFactories.registerCheck<UseEqualsDeleteCheck>(
+        "modernize-use-equals-delete");
     CheckFactories.registerCheck<UseNullptrCheck>("modernize-use-nullptr");
     CheckFactories.registerCheck<UseOverrideCheck>("modernize-use-override");
     CheckFactories.registerCheck<UseUsingCheck>("modernize-use-using");
diff --git a/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.cpp
new file mode 100644
index 00000000000..3500398ed24
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.cpp
@@ -0,0 +1,69 @@
+//===--- UseEqualsDeleteCheck.cpp - clang-tidy-----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "UseEqualsDeleteCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace modernize {
+
+static const char SpecialFunction[] = "SpecialFunction";
+static const char DeletedNotPublic[] = "DeletedNotPublic";
+
+void UseEqualsDeleteCheck::registerMatchers(MatchFinder *Finder) {
+  auto PrivateSpecialFn = cxxMethodDecl(
+      isPrivate(),
+      anyOf(cxxConstructorDecl(anyOf(isDefaultConstructor(),
+                                     isCopyConstructor(), isMoveConstructor())),
+            cxxMethodDecl(
+                anyOf(isCopyAssignmentOperator(), isMoveAssignmentOperator())),
+            cxxDestructorDecl()));
+
+  Finder->addMatcher(
+      cxxMethodDecl(
+          PrivateSpecialFn,
+          unless(anyOf(hasBody(stmt()), isDefaulted(), isDeleted(),
+                       // Ensure that all methods except private special member
+                       // functions are defined.
+                       hasParent(cxxRecordDecl(hasMethod(unless(
+                           anyOf(PrivateSpecialFn, hasBody(stmt()), isPure(),
+                                 isDefaulted(), isDeleted()))))))))
+          .bind(SpecialFunction),
+      this);
+
+  Finder->addMatcher(
+      cxxMethodDecl(isDeleted(), unless(isPublic())).bind(DeletedNotPublic),
+      this);
+}
+
+void UseEqualsDeleteCheck::check(const MatchFinder::MatchResult &Result) {
+  if (const auto *Func =
+          Result.Nodes.getNodeAs<CXXMethodDecl>(SpecialFunction)) {
+    SourceLocation EndLoc = Lexer::getLocForEndOfToken(
+        Func->getLocEnd(), 0, *Result.SourceManager, getLangOpts());
+
+    // FIXME: Improve FixItHint to make method public
+    diag(Func->getLocation(),
+         "use '= delete' to prohibit calling of a special member function")
+        << FixItHint::CreateInsertion(EndLoc, " = delete");
+  } else if (const auto *Func =
+                 Result.Nodes.getNodeAs<CXXMethodDecl>(DeletedNotPublic)) {
+    // FIXME: Add FixItHint to make method public
+    diag(Func->getLocation(), "deleted member function should be public");
+  }
+}
+
+} // namespace modernize
+} // namespace tidy
+} // namespace clang
diff --git a/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
new file mode 100644
index 00000000000..1daa1a8575e
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.h
@@ -0,0 +1,50 @@
+//===--- UseEqualsDeleteCheck.h - clang-tidy---------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_EQUALS_DELETE_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_EQUALS_DELETE_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace modernize {
+
+/// \brief Mark unimplemented private special member functions with '= delete'.
+/// \code
+///   struct A {
+///   private:
+///     A(const A&);
+///     A& operator=(const A&);
+///   };
+/// \endcode
+/// Is converted to:
+/// \code
+///   struct A {
+///   private:
+///     A(const A&) = delete;
+///     A& operator=(const A&) = delete;
+///   };
+/// \endcode
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/modernize-use-equals-delete.html
+class UseEqualsDeleteCheck : public ClangTidyCheck {
+public:
+  UseEqualsDeleteCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace modernize
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_EQUALS_DELETE_H
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 4c54d877216..f7b5cf6fd57 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -91,6 +91,11 @@ Improvements to clang-tidy
   <http://clang.llvm.org/extra/clang-tidy/checks/modernize-use-auto.html>`_ check
   now warns about variable declarations that are initialized with a cast.
 
+- New `modernize-use-equals-delete
+  <http://clang.llvm.org/extra/clang-tidy/checks/modernize-use-equals-delete.html>`_ check
+
+  Adds ``= delete`` to unimplemented private special member functions.
+
 - New `mpi-buffer-deref
   <http://clang.llvm.org/extra/clang-tidy/checks/mpi-buffer-deref.html>`_ check
 
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index c9069a7f102..e22f2dc5049 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -111,6 +111,7 @@ Clang-Tidy Checks
    modernize-use-bool-literals
    modernize-use-default
    modernize-use-emplace
+   modernize-use-equals-delete
    modernize-use-nullptr
    modernize-use-override
    modernize-use-using
diff --git a/clang-tools-extra/docs/clang-tidy/checks/modernize-use-default.rst b/clang-tools-extra/docs/clang-tidy/checks/modernize-use-default.rst
index 157a337c97b..a041ce76b53 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/modernize-use-default.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/modernize-use-default.rst
@@ -25,5 +25,4 @@ defaulted functions as trivial.
   A::~A() = default;
 
 .. note::
-  Copy-constructor, copy-assignment operator, move-constructor and
-  move-assignment operator are not supported yet.
+  Move-constructor and move-assignment operator are not supported yet.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/modernize-use-equals-delete.rst b/clang-tools-extra/docs/clang-tidy/checks/modernize-use-equals-delete.rst
new file mode 100644
index 00000000000..bfa54e4e8e9
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/modernize-use-equals-delete.rst
@@ -0,0 +1,25 @@
+.. title:: clang-tidy - modernize-use-equals-delete
+
+modernize-use-equals-delete
+===========================
+
+This check marks unimplemented private special member functions with ``= delete``.
+To avoid false-positives, this check only applies in a translation unit that has
+all other member functions implemented.
+
+.. code-block:: c++
+
+  struct A {
+  private:
+    A(const A&);
+    A& operator=(const A&);
+  };
+
+  // becomes
+
+  struct A {
+  private:
+    A(const A&) = delete;
+    A& operator=(const A&) = delete;
+  };
+
diff --git a/clang-tools-extra/test/clang-tidy/modernize-use-equals-delete.cpp b/clang-tools-extra/test/clang-tidy/modernize-use-equals-delete.cpp
new file mode 100644
index 00000000000..f6cc3102274
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/modernize-use-equals-delete.cpp
@@ -0,0 +1,134 @@
+// RUN: %check_clang_tidy %s modernize-use-equals-delete %t
+
+struct PositivePrivate {
+private:
+  PositivePrivate();
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositivePrivate() = delete;
+  PositivePrivate(const PositivePrivate &);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositivePrivate(const PositivePrivate &) = delete;
+  PositivePrivate &operator=(const PositivePrivate &);
+  // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositivePrivate &operator=(const PositivePrivate &) = delete;
+  PositivePrivate(PositivePrivate &&);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositivePrivate(PositivePrivate &&) = delete;
+  PositivePrivate &operator=(PositivePrivate &&);
+  // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositivePrivate &operator=(PositivePrivate &&) = delete;
+  ~PositivePrivate();
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: ~PositivePrivate() = delete;
+};
+
+struct NegativePublic {
+  NegativePublic(const NegativePublic &);
+};
+
+struct NegativeProtected {
+protected:
+  NegativeProtected(const NegativeProtected &);
+};
+
+struct PositiveInlineMember {
+  int foo() { return 0; }
+
+private:
+  PositiveInlineMember(const PositiveInlineMember &);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositiveInlineMember(const PositiveInlineMember &) = delete;
+};
+
+struct PositiveOutOfLineMember {
+  int foo();
+
+private:
+  PositiveOutOfLineMember(const PositiveOutOfLineMember &);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositiveOutOfLineMember(const PositiveOutOfLineMember &) = delete;
+};
+
+int PositiveOutOfLineMember::foo() { return 0; }
+
+struct PositiveAbstractMember {
+  virtual int foo() = 0;
+
+private:
+  PositiveAbstractMember(const PositiveAbstractMember &);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositiveAbstractMember(const PositiveAbstractMember &) = delete;
+};
+
+struct NegativeMemberNotImpl {
+  int foo();
+
+private:
+  NegativeMemberNotImpl(const NegativeMemberNotImpl &);
+};
+
+struct NegativeStaticMemberNotImpl {
+  static int foo();
+
+private:
+  NegativeStaticMemberNotImpl(const NegativeStaticMemberNotImpl &);
+};
+
+struct NegativeInline {
+private:
+  NegativeInline(const NegativeInline &) {}
+};
+
+struct NegativeOutOfLine {
+private:
+  NegativeOutOfLine(const NegativeOutOfLine &);
+};
+
+NegativeOutOfLine::NegativeOutOfLine(const NegativeOutOfLine &) {}
+
+struct NegativeConstructNotImpl {
+  NegativeConstructNotImpl();
+
+private:
+  NegativeConstructNotImpl(const NegativeConstructNotImpl &);
+};
+
+struct PositiveDefaultedConstruct {
+  PositiveDefaultedConstruct() = default;
+
+private:
+  PositiveDefaultedConstruct(const PositiveDefaultedConstruct &);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositiveDefaultedConstruct(const PositiveDefaultedConstruct &) = delete;
+};
+
+struct PositiveDeletedConstruct {
+  PositiveDeletedConstruct() = delete;
+
+private:
+  PositiveDeletedConstruct(const PositiveDeletedConstruct &);
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use '= delete' to prohibit calling of a special member function [modernize-use-equals-delete]
+  // CHECK-FIXES: PositiveDeletedConstruct(const PositiveDeletedConstruct &) = delete;
+};
+
+struct NegativeDefaulted {
+private:
+  NegativeDefaulted(const NegativeDefaulted &) = default;
+};
+
+struct PrivateDeleted {
+private:
+  PrivateDeleted(const PrivateDeleted &) = delete;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: deleted member function should be public [modernize-use-equals-delete]
+};
+
+struct ProtectedDeleted {
+protected:
+  ProtectedDeleted(const ProtectedDeleted &) = delete;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: deleted member function should be public [modernize-use-equals-delete]
+};
+
+struct PublicDeleted {
+public:
+  PublicDeleted(const PublicDeleted &) = delete;
+};