Fixed #2770 (False positives (scope can be reduced / variable is assigned value that is never used))

lib/checkother.cpp

@@ -2230,6 +2230,15 @@ void CheckOther::functionVariableUsage()
                 else
                     variables.modified(tok->varId());
             }
+
+            else if (tok->isAssignmentOp())
+            {
+                for (const Token *tok2 = tok->next(); tok2 && tok2->str() != ";"; tok2 = tok2->next())
+                {
+                    if (tok2->varId())
+                        variables.read(tok2->varId());
+                }
+            }
         }
 
         // Check usage of all variables in the current scope..
@@ -2473,19 +2482,13 @@ void CheckOther::lookupVar(const Token *tok1, const std::string &varname)
                     for_or_while = true;
             }
 
-            if (Token::simpleMatch(tok, "do {"))
+            else if (Token::simpleMatch(tok, "do {"))
                 for_or_while = true;
 
             // possible unexpanded macro hiding for/while..
-            if (Token::Match(tok->previous(), "[;{}] %type% {"))
+            else if (tok->str() != "else" && Token::Match(tok->previous(), "[;{}] %type% {"))
             {
-                bool upper = true;
-                for (unsigned int i = 0; i < tok->str().length(); ++i)
-                {
-                    if (!std::isupper(tok->str()[i]))
-                        upper = false;
-                }
-                for_or_while |= upper;
+                for_or_while = true;
             }
 
             if (parlevel == 0 && (tok->str() == ";"))

test/testother.cpp

@@ -60,6 +60,7 @@ private:
         TEST_CASE(varScope9);		// classes may have extra side-effects
         TEST_CASE(varScope10);      // Undefined macro FOR
         TEST_CASE(varScope11);		// #2475 - struct initialization is not inner scope
+        TEST_CASE(varScope12);		// variable usage in inner loop
 
         TEST_CASE(oldStylePointerCast);
 
@@ -686,6 +687,17 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void varScope12()
+    {
+        // #2770
+        varScope("void f() {\n"
+                 "    int i = 0;\n"
+                 "    forever {\n"
+                 "        if (i++ == 42) { break; }\n"
+                 "    }\n"
+                 "}");
+        ASSERT_EQUALS("", errout.str());
+    }
 
     void checkOldStylePointerCast(const char code[])
     {

test/testunusedvar.cpp

@@ -2394,6 +2394,12 @@ private:
                               "    a |= b;\n"
                               "}\n");
         ASSERT_EQUALS("[test.cpp:3]: (style) Variable 'a' is assigned a value that is never used\n", errout.str());
+
+        functionVariableUsage("void foo() {\n"
+                              "    int a = 1;\n"
+                              "    (b).x += a;\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void localvarFor()