Don't suggest const for smartptr::get() (#5126)

* Don't suggest const for smartptr::get()

* Fix test

* Fix merge

* get() doesn't change a smartpointer

* Parentheses

cfg/std.cfg

@@ -8586,7 +8586,6 @@ initializer list (7) string& replace (const_iterator i1, const_iterator i2, init
     <use-retval/>
     <leak-ignore/>
     <noreturn>false</noreturn>
-    <const/>
     <returnValue type="void *"/>
   </function>
   <function name="std::auto_ptr::reset,std::shared_ptr::reset,std::unique_ptr::reset,std::weak_ptr::reset">

lib/astutils.cpp

@@ -2531,7 +2531,7 @@ bool isVariableChanged(const Token *tok, int indirect, const Settings *settings,
                 return false;
             }
         }
-        if (settings && settings->library.isFunctionConst(ftok))
+        if ((settings && settings->library.isFunctionConst(ftok)) || (astIsSmartPointer(tok) && ftok->str() == "get")) // TODO: replace with action/yield?
             return false;
 
         const Function * fun = ftok->function();

test/cfg/std.cpp

@@ -4724,6 +4724,14 @@ void smartPtr_get()
     *p = 1;
 }
 
+void smartPtr_get2(std::vector<std::unique_ptr<int>>& v) 
+{
+    for (auto& u : v) {
+        int* p = u.get();
+        *p = 0;
+    }
+}
+
 void smartPtr_reset()
 {
     std::unique_ptr<int> p(new int());

test/testclass.cpp

@@ -6532,7 +6532,7 @@ private:
                       errout.str());
 
         checkConst("struct S {\n"
-                   "    bool f() { return p.get() != nullptr; }\n"
+                   "    bool f() { return p != 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",