[clang-tidy] Fix DanglingHandleCheck for the correct conversion opera…

…tion between basic_string and basic_string_view.

Summary:
Fix DanglingHandleCheck to handle the final implementation of std::string and std::string_view.
These use a conversion operator instead of a conversion constructor.

Reviewers: hokein

Subscribers: klimek, xazax.hun, cfe-commits

Differential Revision: https://reviews.llvm.org/D41779

llvm-svn: 322002

clang-tools-extra/clang-tidy/bugprone/DanglingHandleCheck.cpp

@@ -25,8 +25,12 @@ namespace {
 ast_matchers::internal::BindableMatcher<Stmt>
 handleFrom(const ast_matchers::internal::Matcher<RecordDecl> &IsAHandle,
            const ast_matchers::internal::Matcher<Expr> &Arg) {
-  return cxxConstructExpr(hasDeclaration(cxxMethodDecl(ofClass(IsAHandle))),
-                          hasArgument(0, Arg));
+  return expr(
+      anyOf(cxxConstructExpr(hasDeclaration(cxxMethodDecl(ofClass(IsAHandle))),
+                             hasArgument(0, Arg)),
+            cxxMemberCallExpr(hasType(cxxRecordDecl(IsAHandle)),
+                              callee(memberExpr(member(cxxConversionDecl()))),
+                              on(Arg))));
 }
 
 ast_matchers::internal::Matcher<Stmt> handleFromTemporaryValue(

clang-tools-extra/test/clang-tidy/bugprone-dangling-handle.cpp

@@ -45,10 +45,15 @@ class map {
   value_type& operator[](Key&& key);
 };
 
+class basic_string_view;
+
 class basic_string {
  public:
   basic_string();
   basic_string(const char*);
+
+  operator basic_string_view() const noexcept;
+
   ~basic_string();
 };
 
@@ -57,7 +62,6 @@ typedef basic_string string;
 class basic_string_view {
  public:
   basic_string_view(const char*);
-  basic_string_view(const basic_string&);
 };
 
 typedef basic_string_view string_view;