[clang-tidy] Now adding correct misc-move-const-arg documentation ;]

+ brushed the code a bit and renamed the test file to match the check name

llvm-svn: 267592

3 files changed, 20 insertions, 21 deletions

diff --git a/clang-tools-extra/clang-tidy/misc/MoveConstantArgumentCheck.cpp b/clang-tools-extra/clang-tidy/misc/MoveConstantArgumentCheck.cpp
index f38b49be8ea..d8e817523b8 100644
--- a/clang-tools-extra/clang-tidy/misc/MoveConstantArgumentCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/MoveConstantArgumentCheck.cpp
@@ -20,16 +20,15 @@ using namespace ast_matchers;
 void MoveConstantArgumentCheck::registerMatchers(MatchFinder *Finder) {
   if (!getLangOpts().CPlusPlus)
     return;
-  Finder->addMatcher(callExpr(unless(isInTemplateInstantiation()),
-                              callee(functionDecl(hasName("::std::move"))))
+  Finder->addMatcher(callExpr(callee(functionDecl(hasName("::std::move"))),
+                              argumentCountIs(1),
+                              unless(isInTemplateInstantiation()))
                          .bind("call-move"),
                      this);
 }
 
 void MoveConstantArgumentCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *CallMove = Result.Nodes.getNodeAs<CallExpr>("call-move");
-  if (CallMove->getNumArgs() != 1)
-    return;
   const Expr *Arg = CallMove->getArg(0);
   SourceManager &SM = Result.Context->getSourceManager();
 
@@ -43,12 +42,12 @@ void MoveConstantArgumentCheck::check(const MatchFinder::MatchResult &Result) {
     if (!FileMoveRange.isValid())
       return;
     bool IsVariable = isa<DeclRefExpr>(Arg);
-    auto Diag =
-        diag(FileMoveRange.getBegin(), "std::move of the %select{|const }0"
-                                       "%select{expression|variable}1 "
-                                       "%select{|of trivially-copyable type }2"
-                                       "has no effect; remove std::move()")
-        << IsConstArg << IsVariable << IsTriviallyCopyable;
+    auto Diag = diag(FileMoveRange.getBegin(),
+                     "std::move of the %select{|const }0"
+                     "%select{expression|variable}1 "
+                     "%select{|of a trivially-copyable type }2"
+                     "has no effect; remove std::move()")
+                << IsConstArg << IsVariable << IsTriviallyCopyable;
 
     auto BeforeArgumentsRange = Lexer::makeFileCharRange(
         CharSourceRange::getCharRange(CallMove->getLocStart(),
diff --git a/clang-tools-extra/docs/clang-tidy/checks/misc-move-const-arg.rst b/clang-tools-extra/docs/clang-tidy/checks/misc-move-const-arg.rst
index b09e0a1cf23..86dd9fa0670 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/misc-move-const-arg.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/misc-move-const-arg.rst
@@ -3,13 +3,13 @@
 misc-move-const-arg
 ===================
 
-The check warns if the result of ``std::move(x)`` is bound to a constant
-reference argument, e.g.:
+The check warns if ``std::move()`` is called with a constant argument or an
+argument of a trivially-copyable type, e.g.:
 
 .. code:: c++
 
-  void f(const string&);
-  void g() {
-    string s;
-    F(std::move(s));  // Warning here. std::move() is not moving anything.
-  }
+  const string s;
+  return std::move(s);  // Warning: std::move of the const variable has no effect
+
+  int x;
+  return std::move(x);  // Warning: std::move of the variable of a trivially-copyable type has no effect
diff --git a/clang-tools-extra/test/clang-tidy/move-const-arg.cpp b/clang-tools-extra/test/clang-tidy/misc-move-const-arg.cpp
index 015c1a39049..beb4078bdbe 100644
--- a/clang-tools-extra/test/clang-tidy/move-const-arg.cpp
+++ b/clang-tools-extra/test/clang-tidy/misc-move-const-arg.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s misc-move-const-arg %t -- -- -std=c++11
+// RUN: %check_clang_tidy %s misc-move-const-arg %t
 
 namespace std {
 template <typename> struct remove_reference;
@@ -23,19 +23,19 @@ public:
 
 int f1() {
   return std::move(42);
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the expression of trivially-copyable type has no effect; remove std::move() [misc-move-const-arg]
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the expression of a trivially-copyable type has no effect; remove std::move() [misc-move-const-arg]
   // CHECK-FIXES: return 42;
 }
 
 int f2(int x2) {
   return std::move(x2);
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable of trivially-copyable type
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable of a trivially-copyable type
   // CHECK-FIXES: return x2;
 }
 
 int *f3(int *x3) {
   return std::move(x3);
-  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable of trivially-copyable type
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: std::move of the variable of a trivially-copyable type
   // CHECK-FIXES: return x3;
 }