Fix #11626 FN functionConst with non-dereferenceable pointer access (#5074)

* Partial fix for #11626 FN functionConst with non-dereferenceable pointer access

* Fix #11626 FN functionConst with non-dereferenceable pointer access

* Fix test

cfg/std.cfg

@@ -8555,6 +8555,13 @@ initializer list (7) string& replace (const_iterator i1, const_iterator i2, init
     <container yields="end-iterator"/>
     <returnValue type="iterator" container="1"/>
   </function>
+  <function name="std::auto_ptr::get,std::shared_ptr::get,std::unique_ptr::get,std::weak_ptr::get">
+    <use-retval/>
+    <leak-ignore/>
+    <noreturn>false</noreturn>
+    <const/>
+    <returnValue type="void *"/>
+  </function>
   <memory>
     <alloc init="false" buffer-size="malloc">malloc</alloc>
     <alloc init="true" buffer-size="calloc">calloc</alloc>

lib/checkclass.cpp

@@ -2472,8 +2472,9 @@ bool CheckClass::checkConstFunc(const Scope *scope, const Function *func, bool&
                     ;
                 else if (var->smartPointerType() && var->smartPointerType()->classScope && isConstMemberFunc(var->smartPointerType()->classScope, end)) {
                     ;
-                }
-                else if (hasOverloadedMemberAccess(end, var->typeScope())) {
+                } else if (var->isSmartPointer() && Token::simpleMatch(tok1->next(), ".") && tok1->next()->originalName().empty() && mSettings->library.isFunctionConst(end)) {
+                    ;
+                } else if (hasOverloadedMemberAccess(end, var->typeScope())) {
                     ;
                 } else if (!var->typeScope() || !isConstMemberFunc(var->typeScope(), end))
                     return false;

test/cfg/std.cpp

@@ -36,6 +36,7 @@
 #include <istream>
 #include <iterator>
 #include <map>
+#include <memory>
 #include <numeric>
 #include <string_view>
 #include <unordered_map>
@@ -4703,4 +4704,13 @@ void beginEnd()
     std::cend(arr);
     //cppcheck-suppress ignoredReturnValue
     std::crend(arr);
+}
+
+void smartPtr_get()
+{
+    std::unique_ptr<int> p;
+    //cppcheck-suppress ignoredReturnValue
+    p.get();
+    //cppcheck-suppress nullPointer
+    *p = 1;
 }

test/testautovariables.cpp

@@ -2981,7 +2981,7 @@ private:
               "    return ptr.get();\n"
               "}\n");
         ASSERT_EQUALS(
-            "[test.cpp:4] -> [test.cpp:3] -> [test.cpp:4]: (error) Returning object that points to local variable 'ptr' that will be invalid when returning.\n",
+            "[test.cpp:4] -> [test.cpp:3] -> [test.cpp:4]: (error) Returning pointer to local variable 'ptr' that will be invalid when returning.\n",
             errout.str());
     }
     void danglingLifetime() {

test/testclass.cpp

@@ -36,31 +36,10 @@ public:
     TestClass() : TestFixture("TestClass") {}
 
 private:
-    Settings settings0 = settingsBuilder().severity(Severity::style).build();
-    Settings settings1 = settingsBuilder().severity(Severity::warning).build();
+    Settings settings0 = settingsBuilder().severity(Severity::style).library("std.cfg").build();
+    Settings settings1 = settingsBuilder().severity(Severity::warning).library("std.cfg").build();
 
     void run() override {
-        // Load std.cfg configuration
-        {
-            const char xmldata[] = "<?xml version=\"1.0\"?>\n"
-                                   "<def>\n"
-                                   "  <memory>\n"
-                                   "    <alloc init=\"false\">malloc</alloc>\n"
-                                   "    <dealloc>free</dealloc>\n"
-                                   "  </memory>\n"
-                                   "  <smart-pointer class-name=\"std::shared_ptr\"/>\n"
-                                   "  <container id=\"stdVector\" startPattern=\"std :: vector &lt;\" itEndPattern=\"&gt; :: const_iterator\">\n"
-                                   "    <access>\n"
-                                   "      <function name=\"begin\" yields=\"start-iterator\"/>\n"
-                                   "      <function name=\"end\" yields=\"end-iterator\"/>\n"
-                                   "    </access>\n"
-                                   "  </container>\n"
-                                   "</def>";
-            ASSERT(settings0.library.loadxmldata(xmldata, sizeof(xmldata)));
-            ASSERT(settings1.library.loadxmldata(xmldata, sizeof(xmldata)));
-        }
-
-
         TEST_CASE(virtualDestructor1);      // Base class not found => no error
         TEST_CASE(virtualDestructor2);      // Base class doesn't have a destructor
         TEST_CASE(virtualDestructor3);      // Base class has a destructor, but it's not virtual
@@ -6529,6 +6508,13 @@ private:
                       "[test.cpp:3]: (style, inconclusive) Technically the member function 'S::g' can be const.\n"
                       "[test.cpp:4]: (style, inconclusive) Technically the member function 'S::h' can be const.\n",
                       errout.str());
+
+        checkConst("struct S {\n"
+                   "    bool f() { return p.get() != nullptr; }\n"
+                   "    std::shared_ptr<int> p;\n"
+                   "};\n");
+        ASSERT_EQUALS("[test.cpp:2]: (style, inconclusive) Technically the member function 'S::f' can be const.\n",
+                      errout.str());
     }
 
     void const89() { // #11654