Fix #13787 nullptr dereference in autoVariables() (danmar#7471)

Co-authored-by: chrchr-github <[email protected]>

Author: chrchr-github

lib/checkautovariables.cpp

@@ -58,7 +58,7 @@ static bool isPtrArg(const Token *tok)
 static bool isArrayArg(const Token *tok, const Settings& settings)
 {
     const Variable *var = tok->variable();
-    return (var && var->isArgument() && var->isArray() && !settings.library.isentrypoint(var->scope()->className));
+    return (var && var->isArgument() && var->isArray() && (!var->scope() || !settings.library.isentrypoint(var->scope()->className)));
 }
 
 static bool isArrayVar(const Token *tok)

test/testautovariables.cpp

@@ -165,6 +165,7 @@ class TestAutoVariables : public TestFixture {
         TEST_CASE(invalidLifetime);
         TEST_CASE(deadPointer);
         TEST_CASE(splitNamespaceAuto); // crash #10473
+        TEST_CASE(incompleteTypeArray);
     }
 
 
@@ -4696,6 +4697,14 @@ class TestAutoVariables : public TestFixture {
         ASSERT_EQUALS("", errout_str());
     }
 
+    void incompleteTypeArray() { // #13787
+        check("struct S (*a[10]);\n"
+              "void f(int i, struct S* p) {\n"
+              "    a[i] = &p[i];\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str()); // don't crash
+    }
+
 };
 
 REGISTER_TEST(TestAutoVariables)