ClangTidy misc-argument-comment check: don't check arguments to template parameter packs.

[alexfh]

Summary

This disables this check for std::bind and similar functions that use
parameter packs to forward arguments to a different function. Name of the
parameter pack argument doesn't matter.

[klimek]

clang-tidy/misc/ArgumentCommentCheck.cpp

123

Can that one actually happen? Shouldn't that be an assert?

[alexfh]

clang-tidy/misc/ArgumentCommentCheck.cpp

123

Sure it can. We're looking at template parameter packs here, which can then instantiate to multiple parameters.

This is tested by the "variadic2(/*zzZ=*/0, /*xxx=*/1, /*yyy=*/2);" line. The last argument of it.

[klimek]

lg

clang-tidy/misc/ArgumentCommentCheck.cpp

123

Ah, because this is the function definition, which doesn't know how many parameters are actually given. Perhaps add a comment?

[alexfh]

clang-tidy/misc/ArgumentCommentCheck.cpp

123

Added a comment.

clang-tidy/misc/ArgumentCommentCheck.cpp

void ArgumentCommentCheck::checkCallArgs(ASTContext *Ctx,
   Callee = Callee->getFirstDecl();
   for (unsigned i = 0,
                 e = std::min<unsigned>(Args.size(), Callee->getNumParams());
        i != e; ++i) {
     const ParmVarDecl *PVD = Callee->getParamDecl(i);
     IdentifierInfo *II = PVD->getIdentifier();
     if (!II)
       continue;
+    if (auto Template = Callee->getTemplateInstantiationPattern()) {
+      if (Template->getNumParams() <= i ||
+          Template->getParamDecl(i)->isParameterPack()) {
+        continue;
+      }
+    }
 
     SourceLocation BeginSLoc, EndSLoc = Args[i]->getLocStart();
     if (i == 0)
       BeginSLoc = ArgBeginLoc;
     else
       BeginSLoc = Args[i - 1]->getLocEnd();
     if (BeginSLoc.isMacroID() || EndSLoc.isMacroID())
       continue;

test/clang-tidy/arg-comments.cpp

 // RUN: clang-tidy --checks='-*,misc-argument-comment' %s -- -std=c++11 | FileCheck %s -implicit-check-not='{{warning:|error:}}'
 
 // FIXME: clang-tidy should provide a -verify mode to make writing these checks
 // easier and more accurate.
 
 void ffff(int xxxx, int yyyy);
 
 void f(int x, int y);
 void g() {
-  // CHECK: [[@LINE+5]]:5: warning: argument name 'y' in comment does not match parameter name 'x'
+  // CHECK: [[@LINE+4]]:5: warning: argument name 'y' in comment does not match parameter name 'x'
   // CHECK: :[[@LINE-3]]:12: note: 'x' declared here
-  // CHECK: [[@LINE+3]]:14: warning: argument name 'z' in comment does not match parameter name 'y'
+  // CHECK: [[@LINE+2]]:14: warning: argument name 'z' in comment does not match parameter name 'y'
   // CHECK: :[[@LINE-5]]:19: note: 'y' declared here
-  // CHECK-NOT: warning
   f(/*y=*/0, /*z=*/0);
 }
 
 struct Closure {};
 
 template <typename T1, typename T2>
 Closure *NewCallback(void (*f)(T1, T2), T1 arg1, T2 arg2) { return nullptr; }
 
 template <typename T1, typename T2>
 Closure *NewPermanentCallback(void (*f)(T1, T2), T1 arg1, T2 arg2) { return nullptr; }
 
 void h() {
   (void)NewCallback(&ffff, /*xxxx=*/11, /*yyyy=*/22);
   (void)NewPermanentCallback(&ffff, /*xxxx=*/11, /*yyyy=*/22);
 }
+
+template<typename... Args>
+void variadic(Args&&... args);
+
+template<typename... Args>
+void variadic2(int zzz, Args&&... args);
+
+void templates() {
+  variadic(/*xxx=*/0, /*yyy=*/1);
+  variadic2(/*zzZ=*/0, /*xxx=*/1, /*yyy=*/2);
+  // CHECK: [[@LINE-1]]:13: warning: argument name 'zzZ' in comment does not match parameter name 'zzz'
+}