Limit variableScope check. Do not check C code if all local variables are declared at function level.

lib/checkother.cpp

@@ -879,6 +879,22 @@ void CheckOther::checkVariableScope()
 
     const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
 
+    // In C it is common practice to declare local variables at the
+    // start of functions.
+    if (mTokenizer->isC()) {
+        // Try to autodetect what coding style is used. If a local variable is
+        // declared in an inner scope then we will warn about all variables.
+        bool limitScope = false;
+        for (const Variable* var : symbolDatabase->variableList()) {
+            if (var && var->isLocal() && var->nameToken()->scope()->type != Scope::ScopeType::eFunction) {
+                limitScope = true;
+                break;
+            }
+        }
+        if (!limitScope)
+            return;
+    }
+
     for (const Variable* var : symbolDatabase->variableList()) {
         if (!var || !var->isLocal() || (!var->isPointer() && !var->isReference() && !var->typeStartToken()->isStandardType()))
             continue;

test/testother.cpp

@@ -1245,6 +1245,16 @@ private:
               "        if (currtime > t) {}\n"
               "    }\n"
               "}", "test.c");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f() {\n"
+              "    time_t currtime;\n"
+              "    if (a) {\n"
+              "        int x = 123;\n"
+              "        currtime = time(&dummy);\n"
+              "        if (currtime > t) {}\n"
+              "    }\n"
+              "}", "test.c");
         ASSERT_EQUALS("[test.c:2]: (style) The scope of the variable 'currtime' can be reduced.\n", errout.str());
     }