FIx FN shadowVariable in static function (#4079)

* FIx FN shadowVariable in static function

* Use functionOf

Author: chrchr-github

lib/checkother.cpp

@@ -3407,7 +3407,8 @@ void CheckOther::checkShadowVariables()
                 continue;
             if (scope.type == Scope::eFunction && scope.className == var.name())
                 continue;
-            if (functionScope->function && functionScope->function->isStatic() && shadowed->variable() && !shadowed->variable()->isLocal())
+            if (functionScope->functionOf && functionScope->functionOf->isClassOrStructOrUnion() && functionScope->function && functionScope->function->isStatic() &&
+                shadowed->variable() && !shadowed->variable()->isLocal())
                 continue;
             shadowError(var.nameToken(), shadowed, (shadowed->varId() != 0) ? "variable" : "function");
         }

test/testother.cpp

@@ -9712,6 +9712,14 @@ class TestOther : public TestFixture {
               "    for (const F& f : fl) {}\n"
               "};\n");
         ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:7]: (style) Local variable 'f' shadows outer variable\n", errout.str());
+
+        check("extern int a;\n"
+              "int a;\n"
+              "static int f(void) {\n"
+              "    int a;\n"
+              "    return 0;\n"
+              "}\n", "test.c");
+        ASSERT_EQUALS("[test.c:1] -> [test.c:4]: (style) Local variable 'a' shadows outer variable\n", errout.str());
     }
 
     void knownArgument() {