Fix #10151 FP eraseDereference when returning iterator from loop (#3787)

lib/checkstl.cpp

@@ -1370,7 +1370,7 @@ void CheckStl::eraseCheckLoopVar(const Scope &scope, const Variable *var)
         // Vector erases are handled by invalidContainer check
         if (isVector(tok->tokAt(-3)))
             continue;
-        if (Token::simpleMatch(tok->astParent(), "="))
+        if (Token::Match(tok->astParent(), "=|return"))
             continue;
         // Iterator is invalid..
         int indentlevel = 0U;

test/teststl.cpp

@@ -4285,6 +4285,15 @@ private:
               "}\n");
         ASSERT_EQUALS("[test.cpp:9]: (error) Out of bounds access in expression 'e[d].begin()' because 'e[d]' is empty.\n",
                       errout.str());
+
+        // #10151
+        check("std::set<int>::iterator f(std::set<int>& s) {\n"
+              "for (auto it = s.begin(); it != s.end(); ++it)\n"
+              "    if (*it == 42)\n"
+              "        return s.erase(it);\n"
+              "    return s.end();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void dereferenceInvalidIterator2() {