[PATCH] D25437: [clang-tidy] Fix template agrument false positives in unused-using-decls.

[Haojian Wu via cfe-commits]

hokein created this revision.
hokein added a subscriber: cfe-commits.

- Fix a false postive when an using class is used in an explicit template 
instantiation.
- Fix a false postive when an using template class is used as template argument.


https://reviews.llvm.org/D25437

Files:
  clang-tidy/misc/UnusedUsingDeclsCheck.cpp
  test/clang-tidy/misc-unused-using-decls.cpp


Index: test/clang-tidy/misc-unused-using-decls.cpp
===================================================================
--- test/clang-tidy/misc-unused-using-decls.cpp
+++ test/clang-tidy/misc-unused-using-decls.cpp
@@ -21,6 +21,13 @@
 class G;
 class H;
 
+template <typename T> class K {};
+template <template <typename> class S>
+class L {};
+
+template <typename T> class M {};
+class N {};
+
 class Base {
  public:
   void f();
@@ -150,6 +157,10 @@
 using ns::AA;
 using ns::ff;
 
+using n::K;
+
+using n::N;
+
 // ----- Usages -----
 void f(B b);
 void g() {
@@ -170,4 +181,11 @@
   int t3 = 0;
   a.func1<AA>(&t3);
   a.func2<int, ff>(t3);
+
+  n::L<K> l;
 }
+
+template<class T>
+void h(n::M<T>* t) {}
+// n::N is using in the explicit template instantiations.
+template void h(n::M<N>* t);
Index: clang-tidy/misc/UnusedUsingDeclsCheck.cpp
===================================================================
--- clang-tidy/misc/UnusedUsingDeclsCheck.cpp
+++ clang-tidy/misc/UnusedUsingDeclsCheck.cpp
@@ -42,6 +42,8 @@
           anyOf(refersToTemplate(templateName().bind("used")),
                 refersToDeclaration(functionDecl().bind("used"))))))),
       this);
+  Finder->addMatcher(loc(templateSpecializationType(
+      hasAnyTemplateArgument(templateArgument().bind("used")))), this);
 }
 
 void UnusedUsingDeclsCheck::check(const MatchFinder::MatchResult &Result) {
@@ -91,6 +93,17 @@
     return;
   }
 
+  if (const auto *Used = Result.Nodes.getNodeAs<TemplateArgument>("used")) {
+    if (Used->getKind() == TemplateArgument::Template) {
+      if (const auto *TD = Used->getAsTemplate().getAsTemplateDecl())
+        removeFromFoundDecls(TD);
+    } else if (Used->getKind() == TemplateArgument::Type) {
+      if (auto *RD = Used->getAsType()->getAsCXXRecordDecl())
+        removeFromFoundDecls(RD);
+    }
+    return;
+  }
+
   if (const auto *Used = Result.Nodes.getNodeAs<TemplateName>("used")) {
     removeFromFoundDecls(Used->getAsTemplateDecl());
     return;



Index: test/clang-tidy/misc-unused-using-decls.cpp
===================================================================
--- test/clang-tidy/misc-unused-using-decls.cpp
+++ test/clang-tidy/misc-unused-using-decls.cpp
@@ -21,6 +21,13 @@
 class G;
 class H;
 
+template <typename T> class K {};
+template <template <typename> class S>
+class L {};
+
+template <typename T> class M {};
+class N {};
+
 class Base {
  public:
   void f();
@@ -150,6 +157,10 @@
 using ns::AA;
 using ns::ff;
 
+using n::K;
+
+using n::N;
+
 // ----- Usages -----
 void f(B b);
 void g() {
@@ -170,4 +181,11 @@
   int t3 = 0;
   a.func1<AA>(&t3);
   a.func2<int, ff>(t3);
+
+  n::L<K> l;
 }
+
+template<class T>
+void h(n::M<T>* t) {}
+// n::N is using in the explicit template instantiations.
+template void h(n::M<N>* t);
Index: clang-tidy/misc/UnusedUsingDeclsCheck.cpp
===================================================================
--- clang-tidy/misc/UnusedUsingDeclsCheck.cpp
+++ clang-tidy/misc/UnusedUsingDeclsCheck.cpp
@@ -42,6 +42,8 @@
           anyOf(refersToTemplate(templateName().bind("used")),
                 refersToDeclaration(functionDecl().bind("used"))))))),
       this);
+  Finder->addMatcher(loc(templateSpecializationType(
+      hasAnyTemplateArgument(templateArgument().bind("used")))), this);
 }
 
 void UnusedUsingDeclsCheck::check(const MatchFinder::MatchResult &Result) {
@@ -91,6 +93,17 @@
     return;
   }
 
+  if (const auto *Used = Result.Nodes.getNodeAs<TemplateArgument>("used")) {
+    if (Used->getKind() == TemplateArgument::Template) {
+      if (const auto *TD = Used->getAsTemplate().getAsTemplateDecl())
+        removeFromFoundDecls(TD);
+    } else if (Used->getKind() == TemplateArgument::Type) {
+      if (auto *RD = Used->getAsType()->getAsCXXRecordDecl())
+        removeFromFoundDecls(RD);
+    }
+    return;
+  }
+
   if (const auto *Used = Result.Nodes.getNodeAs<TemplateName>("used")) {
     removeFromFoundDecls(Used->getAsTemplateDecl());
     return;

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