From f3321c5f68744f2a4188dc49da9d279597e929fe Mon Sep 17 00:00:00 2001
From: Alexander Kornienko <alexfh@google.com>
Date: Fri, 28 Jul 2017 12:46:02 +0000
Subject: [PATCH] [clang-tidy] readability-redundant-declaration: ignore
 friends and macros

llvm-svn: 309379
---
 .../readability/RedundantDeclarationCheck.cpp | 18 ++++++++++--
 .../readability/RedundantDeclarationCheck.h   |  6 ++--
 ...ty-redundant-declaration-ignore-macros.cpp | 22 +++++++++++++++
 .../readability-redundant-declaration.cpp     | 28 ++++++++++++++++++-
 4 files changed, 68 insertions(+), 6 deletions(-)
 create mode 100644 clang-tools-extra/test/clang-tidy/readability-redundant-declaration-ignore-macros.cpp

diff --git a/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
index 29d43c7b779f..1df3f0555b89 100644
--- a/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
@@ -18,11 +18,16 @@ namespace clang {
 namespace tidy {
 namespace readability {
 
+RedundantDeclarationCheck::RedundantDeclarationCheck(StringRef Name,
+                                                     ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)) {}
+
 void RedundantDeclarationCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(
-      namedDecl(
-          anyOf(varDecl(unless(isDefinition())),
-                functionDecl(unless(anyOf(isDefinition(), isDefaulted())))))
+      namedDecl(anyOf(varDecl(unless(isDefinition())),
+                      functionDecl(unless(anyOf(isDefinition(), isDefaulted(),
+                                                hasParent(friendDecl()))))))
           .bind("Decl"),
       this);
 }
@@ -36,6 +41,13 @@ void RedundantDeclarationCheck::check(const MatchFinder::MatchResult &Result) {
     return;
   if (Prev->getLocation() == D->getLocation())
     return;
+  if (IgnoreMacros &&
+      (D->getLocation().isMacroID() || Prev->getLocation().isMacroID()))
+    return;
+  // Don't complain when the previous declaration is a friend declaration.
+  for (const auto &Parent : Result.Context->getParents(*Prev))
+    if (Parent.get<FriendDecl>())
+      return;
 
   const SourceManager &SM = *Result.SourceManager;
 
diff --git a/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.h b/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.h
index 96c483062fab..9be79b848185 100644
--- a/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.h
+++ b/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.h
@@ -22,10 +22,12 @@ namespace readability {
 /// http://clang.llvm.org/extra/clang-tidy/checks/readability-redundant-declaration.html
 class RedundantDeclarationCheck : public ClangTidyCheck {
 public:
-  RedundantDeclarationCheck(StringRef Name, ClangTidyContext *Context)
-      : ClangTidyCheck(Name, Context) {}
+  RedundantDeclarationCheck(StringRef Name, ClangTidyContext *Context);
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  const bool IgnoreMacros;
 };
 
 } // namespace readability
diff --git a/clang-tools-extra/test/clang-tidy/readability-redundant-declaration-ignore-macros.cpp b/clang-tools-extra/test/clang-tidy/readability-redundant-declaration-ignore-macros.cpp
new file mode 100644
index 000000000000..2dc86182606b
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/readability-redundant-declaration-ignore-macros.cpp
@@ -0,0 +1,22 @@
+// RUN: %check_clang_tidy %s readability-redundant-declaration %t -- \
+// RUN:   -config="{CheckOptions: \
+// RUN:             [{key: readability-redundant-declaration.IgnoreMacros, \
+// RUN:               value: 1}]}" \
+// RUN:   -- -std=c++11
+
+extern int Xyz;
+extern int Xyz; // Xyz
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: redundant 'Xyz' declaration [readability-redundant-declaration]
+// CHECK-FIXES: {{^}}// Xyz{{$}}
+
+namespace macros {
+#define DECLARE(x) extern int x
+#define DEFINE(x) extern int x; int x = 42
+DECLARE(test);
+DEFINE(test);
+// CHECK-FIXES: {{^}}#define DECLARE(x) extern int x{{$}}
+// CHECK-FIXES: {{^}}#define DEFINE(x) extern int x; int x = 42{{$}}
+// CHECK-FIXES: {{^}}DECLARE(test);{{$}}
+// CHECK-FIXES: {{^}}DEFINE(test);{{$}}
+
+} // namespace macros
diff --git a/clang-tools-extra/test/clang-tidy/readability-redundant-declaration.cpp b/clang-tools-extra/test/clang-tidy/readability-redundant-declaration.cpp
index e1b8023acbfa..83d1b5bccb25 100644
--- a/clang-tools-extra/test/clang-tidy/readability-redundant-declaration.cpp
+++ b/clang-tools-extra/test/clang-tidy/readability-redundant-declaration.cpp
@@ -1,4 +1,8 @@
-// RUN: %check_clang_tidy %s readability-redundant-declaration %t
+// RUN: %check_clang_tidy %s readability-redundant-declaration %t -- \
+// RUN:   -config="{CheckOptions: \
+// RUN:             [{key: readability-redundant-declaration.IgnoreMacros, \
+// RUN:               value: 0}]}" \
+// RUN:   -- -std=c++11
 
 extern int Xyz;
 extern int Xyz; // Xyz
@@ -42,3 +46,25 @@ struct C2 {
 
 template <class T>
 C2<T>::C2() = default;
+
+void best_friend();
+
+struct Friendly {
+  friend void best_friend();
+  friend void enemy();
+};
+
+void enemy();
+
+namespace macros {
+#define DECLARE(x) extern int x
+#define DEFINE(x) extern int x; int x = 42
+DECLARE(test);
+DEFINE(test);
+// CHECK-MESSAGES: :[[@LINE-1]]:8: warning: redundant 'test' declaration
+// CHECK-FIXES: {{^}}#define DECLARE(x) extern int x{{$}}
+// CHECK-FIXES: {{^}}#define DEFINE(x) extern int x; int x = 42{{$}}
+// CHECK-FIXES: {{^}}DECLARE(test);{{$}}
+// CHECK-FIXES: {{^}}DEFINE(test);{{$}}
+
+} // namespace macros