[clang-tidy] Add new modernize use unary assert check

Patch by: Lilla Barancsuk

Differential Revision: https://reviews.llvm.org/D35257

llvm-svn: 307791

clang-tools-extra/clang-tidy/modernize/CMakeLists.txt

@@ -16,6 +16,7 @@ add_clang_library(clangTidyModernizeModule
   ReplaceRandomShuffleCheck.cpp
   ReturnBracedInitListCheck.cpp
   ShrinkToFitCheck.cpp
+  UnaryStaticAssertCheck.cpp
   UseAutoCheck.cpp
   UseBoolLiteralsCheck.cpp
   UseDefaultMemberInitCheck.cpp

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

@@ -22,6 +22,7 @@
 #include "ReplaceRandomShuffleCheck.h"
 #include "ReturnBracedInitListCheck.h"
 #include "ShrinkToFitCheck.h"
+#include "UnaryStaticAssertCheck.h"
 #include "UseAutoCheck.h"
 #include "UseBoolLiteralsCheck.h"
 #include "UseDefaultMemberInitCheck.h"
@@ -61,6 +62,8 @@ public:
     CheckFactories.registerCheck<ReturnBracedInitListCheck>(
         "modernize-return-braced-init-list");
     CheckFactories.registerCheck<ShrinkToFitCheck>("modernize-shrink-to-fit");
+    CheckFactories.registerCheck<UnaryStaticAssertCheck>(
+        "modernize-unary-static-assert");
     CheckFactories.registerCheck<UseAutoCheck>("modernize-use-auto");
     CheckFactories.registerCheck<UseBoolLiteralsCheck>(
         "modernize-use-bool-literals");

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

@@ -0,0 +1,45 @@
+//===--- UnaryStaticAssertCheck.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 "UnaryStaticAssertCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace modernize {
+
+void UnaryStaticAssertCheck::registerMatchers(MatchFinder *Finder) {
+  if (!getLangOpts().CPlusPlus1z)
+    return;
+
+  Finder->addMatcher(staticAssertDecl().bind("static_assert"), this);
+}
+
+void UnaryStaticAssertCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *MatchedDecl =
+      Result.Nodes.getNodeAs<StaticAssertDecl>("static_assert");
+  const StringLiteral *AssertMessage = MatchedDecl->getMessage();
+
+  SourceLocation Loc = MatchedDecl->getLocation();
+
+  if (!AssertMessage || AssertMessage->getLength() ||
+      AssertMessage->getLocStart().isMacroID() || Loc.isMacroID())
+    return;
+
+  diag(Loc,
+       "use unary 'static_assert' when the string literal is an empty string")
+      << FixItHint::CreateRemoval(AssertMessage->getSourceRange());
+}
+
+} // namespace modernize
+} // namespace tidy
+} // namespace clang

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

@@ -0,0 +1,36 @@
+//===--- UnaryStaticAssertCheck.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_UNARY_STATIC_ASSERT_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_UNARY_STATIC_ASSERT_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace modernize {
+
+/// Replaces a static_assert declaration with an empty message
+/// with the unary version.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/modernize-unary-static-assert.html
+class UnaryStaticAssertCheck : public ClangTidyCheck {
+public:
+  UnaryStaticAssertCheck(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_UNARY_STATIC_ASSERT_H

clang-tools-extra/docs/ReleaseNotes.rst

@@ -108,6 +108,12 @@ Improvements to clang-tidy
   Finds and replaces explicit calls to the constructor in a return statement by
   a braced initializer list so that the return type is not needlessly repeated.
 
+- New `modernize-unary-static-assert-check
+  <http://clang.llvm.org/extra/clang-tidy/checks/modernize-unary-static-assert.html>`_ check
+
+  The check diagnoses any ``static_assert`` declaration with an empty string literal
+  and provides a fix-it to replace the declaration with a single-argument ``static_assert`` declaration.
+
 - Improved `modernize-use-emplace
   <http://clang.llvm.org/extra/clang-tidy/checks/modernize-use-emplace.html>`_ check
 

clang-tools-extra/docs/clang-tidy/checks/list.rst

@@ -132,6 +132,7 @@ Clang-Tidy Checks
    modernize-replace-random-shuffle
    modernize-return-braced-init-list
    modernize-shrink-to-fit
+   modernize-unary-static-assert
    modernize-use-auto
    modernize-use-bool-literals
    modernize-use-default-member-init

clang-tools-extra/docs/clang-tidy/checks/modernize-unary-static-assert.rst

@@ -0,0 +1,25 @@
+.. title:: clang-tidy - modernize-unary-static-assert
+
+modernize-unary-static-assert
+=============================
+
+The check diagnoses any ``static_assert`` declaration with an empty string literal
+and provides a fix-it to replace the declaration with a single-argument ``static_assert`` declaration.
+
+The check is only applicable for C++17 and later code.
+
+The following code:
+
+.. code-block:: c++
+
+  void f_textless(int a) {
+    static_assert(sizeof(a) <= 10, "");
+  }
+
+is replaced by:
+
+.. code-block:: c++
+
+  void f_textless(int a) {
+    static_assert(sizeof(a) <= 10);
+  }

clang-tools-extra/test/clang-tidy/modernize-unary-static-assert.cpp

@@ -0,0 +1,25 @@
+// RUN: %check_clang_tidy %s modernize-unary-static-assert %t -- -- -std=c++1z
+
+#define FOO static_assert(sizeof(a) <= 15, "");
+#define MSG ""
+
+void f_textless(int a) {
+  static_assert(sizeof(a) <= 10, "");
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use unary 'static_assert' when the string literal is an empty string [modernize-unary-static-assert]
+  // CHECK-FIXES: {{^}}  static_assert(sizeof(a) <= 10 );{{$}}
+  static_assert(sizeof(a) <= 12, L"");
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use unary 'static_assert' when
+  // CHECK-FIXES: {{^}}  static_assert(sizeof(a) <= 12 );{{$}}
+  FOO
+  // CHECK-FIXES: {{^}}  FOO{{$}}
+  static_assert(sizeof(a) <= 17, MSG);
+  // CHECK-FIXES: {{^}}  static_assert(sizeof(a) <= 17, MSG);{{$}}
+}
+
+void f_with_tex(int a) {
+  static_assert(sizeof(a) <= 10, "Size of variable a is out of range!");
+}
+
+void f_unary(int a) { static_assert(sizeof(a) <= 10); }
+
+void f_incorrect_assert() { static_assert(""); }