[PATCH] D146904: [clang-tidy] Fix extern fixes in readability-redundant-declaration

[Piotr Zegar via Phabricator via cfe-commits]

PiotrZSL created this revision.
Herald added subscribers: carlosgalvezp, xazax.hun.
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Herald added a project: clang-tools-extra.
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Currently check does not look into LinkageSpecDecl
when removing redundant variable re-declarations.
This were leaving code in non-compiling state.
Fix patch fixes this and adds removal also of 'extern C'.

Fixes: https://github.com/llvm/llvm-project/issues/42068


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D146904

Files:
  clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
  clang-tools-extra/test/clang-tidy/checkers/readability/redundant-declaration.cpp


Index: clang-tools-extra/test/clang-tidy/checkers/readability/redundant-declaration.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/readability/redundant-declaration.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/readability/redundant-declaration.cpp
@@ -120,3 +120,9 @@
 // CHECK-MESSAGES-NOMSCOMPAT: :[[@LINE-1]]:20: warning: redundant 'g' declaration
 // CHECK-FIXES-NOMSCOMPAT: {{^}}// extern g{{$}}
 #endif
+
+// PR42068
+extern "C" int externX;
+int dumyBegin;extern "C" int externX;int dummyEnd;
+// CHECK-MESSAGES: :[[@LINE-1]]:30: warning: redundant 'externX' declaration [readability-redundant-declaration]
+// CHECK-FIXES: {{^}}int dumyBegin;int dummyEnd;{{$}}
Index: clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
+++ clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
@@ -35,7 +35,8 @@
                       functionDecl(unless(anyOf(
                           isDefinition(), isDefaulted(),
                           doesDeclarationForceExternallyVisibleDefinition(),
-                          hasAncestor(friendDecl()))))))
+                          hasAncestor(friendDecl()))))),
+                optionally(hasParent(linkageSpecDecl().bind("extern"))))
           .bind("Decl"),
       this);
 }
@@ -78,9 +79,17 @@
       D->getSourceRange().getEnd(), 0, SM, Result.Context->getLangOpts());
   {
     auto Diag = diag(D->getLocation(), "redundant %0 declaration") << D;
-    if (!MultiVar && !DifferentHeaders)
-      Diag << FixItHint::CreateRemoval(
-          SourceRange(D->getSourceRange().getBegin(), EndLoc));
+    if (!MultiVar && !DifferentHeaders) {
+      SourceLocation BeginLoc;
+      if (const LinkageSpecDecl *Extern =
+              Result.Nodes.getNodeAs<LinkageSpecDecl>("extern");
+          Extern && !Extern->hasBraces())
+        BeginLoc = Extern->getExternLoc();
+      else
+        BeginLoc = D->getSourceRange().getBegin();
+
+      Diag << FixItHint::CreateRemoval(SourceRange(BeginLoc, EndLoc));
+    }
   }
   diag(Prev->getLocation(), "previously declared here", DiagnosticIDs::Note);
 }


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