Fix #13199 nullptr dereference in checkInnerScope() (danmar#6878)

Author: chrchr-github

lib/checkother.cpp

@@ -1254,10 +1254,12 @@ bool CheckOther::checkInnerScope(const Token *tok, const Variable* var, bool& us
                     }
                     if (ftok->function()) {
                         const std::list<Variable> &argvars = ftok->function()->argumentList;
-                        const Variable *argvar = ftok->function()->getArgumentVar(argn);
-                        if (!std::all_of(argvars.cbegin(), argvars.cend(), [&](const Variable &other) {
-                            return &other == argvar || !mayDependOn(other.valueType(), argvar->valueType());
-                        })) return false;
+                        if (const Variable* argvar = ftok->function()->getArgumentVar(argn)) {
+                            if (!std::all_of(argvars.cbegin(), argvars.cend(), [&](const Variable& other) {
+                                return &other == argvar || !mayDependOn(other.valueType(), argvar->valueType());
+                            }))
+                                return false;
+                        }
                     }
                 }
             }

test/testother.cpp

@@ -1843,6 +1843,14 @@ class TestOther : public TestFixture {
               "    printf(\"result: %d\\n\", msg);\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("void g(const char* format, ...);\n"
+              "void f(bool b) {\n"
+              "    const char* s = \"abc\";\n"
+              "    if (b)\n"
+              "       g(\"%d %s\", 1, s);\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3]: (style) The scope of the variable 's' can be reduced.\n", errout_str());
     }
 
 #define checkOldStylePointerCast(...) checkOldStylePointerCast_(__FILE__, __LINE__, __VA_ARGS__)