[clang-tidy][use-internal-linkage]fix false positives for ExportDecl

clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.cpp

@@ -101,7 +101,7 @@ void UseInternalLinkageCheck::registerMatchers(MatchFinder *Finder) {
                 // 3. template
                 isExplicitTemplateSpecialization(),
                 // 4. friend
-                hasAncestor(friendDecl()))));
+                hasAncestor(decl(anyOf(friendDecl(), exportDecl()))))));
   Finder->addMatcher(
       functionDecl(Common, hasBody(), unless(cxxMethodDecl()), unless(isMain()))
           .bind("fn"),

clang-tools-extra/docs/ReleaseNotes.rst

@@ -237,7 +237,8 @@ Changes in existing checks
 - Improved :doc:`misc-use-internal-linkage
   <clang-tidy/checks/misc/use-internal-linkage>` check to insert ``static``
   keyword before type qualifiers such as ``const`` and ``volatile`` and fix
-  false positives for function declaration without body.
+  false positives for function declaration without body and fix false positives
+  for C++20 export declarations.
 
 - Improved :doc:`modernize-avoid-c-arrays
   <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest using 

clang-tools-extra/docs/clang-tidy/checks/misc/use-internal-linkage.rst

@@ -29,6 +29,11 @@ Example:
   void fn3(); // without function body in all declaration, maybe external linkage
   void fn3();
 
+  // export declarations
+  export void fn4() {}
+  export namespace t { void fn5() {} }
+  export int v2;
+
 Options
 -------
 

clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-module.cpp

@@ -0,0 +1,20 @@
+// RUN: %check_clang_tidy -std=c++20 %s misc-use-internal-linkage %t -- -- -I%S/Inputs/use-internal-linkage
+
+module;
+
+export module test;
+
+export void single_export_fn() {}
+export int single_export_var;
+
+export {
+  void group_export_fn1() {}
+  void group_export_fn2() {}
+  int group_export_var1;
+  int group_export_var2;
+}
+
+export namespace aa {
+void namespace_export_fn() {}
+int namespace_export_var;
+} // namespace aa

clang/docs/ReleaseNotes.rst

@@ -926,6 +926,8 @@ AST Matchers
 - Ensure ``hasName`` matches template specializations across inline namespaces,
   making `matchesNodeFullSlow` and `matchesNodeFullFast` consistent.
 
+- Add ``exportDecl`` matches export declaration.
+
 clang-format
 ------------
 

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -1236,6 +1236,17 @@ AST_MATCHER_P(TemplateArgument, equalsIntegralValue,
 extern const internal::VariadicDynCastAllOfMatcher<Stmt,
        ObjCAutoreleasePoolStmt> autoreleasePoolStmt;
 
+/// Matches any export declaration.
+///
+/// Example matches following declarations.
+/// \code
+///   export void foo();
+///   export { void foo(); }
+///   export namespace { void foo(); }
+///   export int v;
+/// \endcode
+extern const internal::VariadicDynCastAllOfMatcher<Decl, ExportDecl> exportDecl;
+
 /// Matches any value declaration.
 ///
 /// Example matches A, B, C and F

clang/lib/ASTMatchers/ASTMatchersInternal.cpp

@@ -799,6 +799,7 @@ const internal::VariadicDynCastAllOfMatcher<TypeLoc, ElaboratedTypeLoc>
 
 const internal::VariadicDynCastAllOfMatcher<Stmt, UnaryExprOrTypeTraitExpr>
     unaryExprOrTypeTraitExpr;
+const internal::VariadicDynCastAllOfMatcher<Decl, ExportDecl> exportDecl;
 const internal::VariadicDynCastAllOfMatcher<Decl, ValueDecl> valueDecl;
 const internal::VariadicDynCastAllOfMatcher<Decl, CXXConstructorDecl>
     cxxConstructorDecl;