[clang-tidy] Simplify const params check

clang-tools-extra/clang-tidy/readability/AvoidConstParamsInDecls.h

 // them.
 class AvoidConstParamsInDecls : public ClangTidyCheck {
 public:
   AvoidConstParamsInDecls(StringRef Name, ClangTidyContext *Context)
       : ClangTidyCheck(Name, Context) {}
 
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+  llvm::Optional<TraversalKind> getCheckTraversalKind() const override {
+    return TK_IgnoreUnlessSpelledInSource;
+  }
 };
 
 } // namespace readability
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOID_CONST_PARAMS_IN_DECLS_H

clang-tools-extra/clang-tidy/readability/AvoidConstParamsInDecls.cpp

 
 } // namespace
 
 void AvoidConstParamsInDecls::registerMatchers(MatchFinder *Finder) {
   const auto ConstParamDecl =
       parmVarDecl(hasType(qualType(isConstQualified()))).bind("param");
   Finder->addMatcher(
       functionDecl(unless(isDefinition()),
-                   // Lambdas are always their own definition, but they
-                   // generate a non-definition FunctionDecl too. Ignore those.
-                   // Class template instantiations have a non-definition
-                   // CXXMethodDecl for methods that aren't used in this
-                   // translation unit. Ignore those, as the template will have
-                   // already been checked.
-                   unless(cxxMethodDecl(ofClass(cxxRecordDecl(anyOf(
-                       isLambda(), ast_matchers::isTemplateInstantiation()))))),
                    has(typeLoc(forEach(ConstParamDecl))))
           .bind("func"),
       this);
 }
 
 // Re-lex the tokens to get precise location of last 'const'
 static llvm::Optional<Token> constTok(CharSourceRange Range,
                                       const MatchFinder::MatchResult &Result) {