Dont stop analysis when an unrelated class variable is changed (#3518)

lib/astutils.cpp

@@ -720,7 +720,7 @@ bool isAliased(const Variable *var)
     return isAliased(start, var->scope()->bodyEnd, var->declarationId());
 }
 
-bool exprDependsOnThis(const Token* expr, nonneg int depth)
+bool exprDependsOnThis(const Token* expr, bool onVar, nonneg int depth)
 {
     if (!expr)
         return false;
@@ -743,13 +743,13 @@ bool exprDependsOnThis(const Token* expr, nonneg int depth)
             nestedIn = nestedIn->nestedIn;
         }
         return nestedIn == expr->function()->nestedIn;
-    } else if (Token::Match(expr, "%var%") && expr->variable()) {
+    } else if (onVar && Token::Match(expr, "%var%") && expr->variable()) {
         const Variable* var = expr->variable();
         return (var->isPrivate() || var->isPublic() || var->isProtected());
     }
     if (Token::simpleMatch(expr, "."))
-        return exprDependsOnThis(expr->astOperand1(), depth);
+        return exprDependsOnThis(expr->astOperand1(), onVar, depth);
-    return exprDependsOnThis(expr->astOperand1(), depth) || exprDependsOnThis(expr->astOperand2(), depth);
+    return exprDependsOnThis(expr->astOperand1(), onVar, depth) || exprDependsOnThis(expr->astOperand2(), onVar, depth);
 }
 
 static bool hasUnknownVars(const Token* startTok)

lib/astutils.h

@@ -144,7 +144,7 @@ bool extractForLoopValues(const Token *forToken,
 
 bool precedes(const Token * tok1, const Token * tok2);
 
-bool exprDependsOnThis(const Token* expr, nonneg int depth = 0);
+bool exprDependsOnThis(const Token* expr, bool onVar = true, nonneg int depth = 0);
 
 struct ReferenceToken {
     const Token* token;

lib/valueflow.cpp

@@ -1938,6 +1938,8 @@ static bool bifurcate(const Token* tok, const std::set<nonneg int>& varids, cons
     return false;
 }
 
+static bool isContainerSizeChanged(const Token* tok, const Settings* settings = nullptr, int depth = 20);
+
 struct ValueFlowAnalyzer : Analyzer {
     const TokenList* tokenlist;
     ProgramMemoryState pms;
@@ -1977,6 +1979,9 @@ struct ValueFlowAnalyzer : Analyzer {
     virtual bool dependsOnThis() const {
         return false;
     }
+    virtual bool isVariable() const {
+        return false;
+    }
 
     virtual bool invalid() const {
         return false;
@@ -2330,8 +2335,7 @@ struct ValueFlowAnalyzer : Analyzer {
             if (a != Action::None)
                 return a;
         }
-
+        if (dependsOnThis() && exprDependsOnThis(tok, !isVariable()))
-        if (dependsOnThis() && exprDependsOnThis(tok))
             return isThisModified(tok);
 
         // bailout: global non-const variables
@@ -2674,6 +2678,10 @@ struct ExpressionAnalyzer : SingleValueFlowAnalyzer {
     virtual bool isGlobal() const OVERRIDE {
         return !local;
     }
+
+    virtual bool isVariable() const OVERRIDE {
+        return expr->varId() > 0;
+    }
 };
 
 struct OppositeExpressionAnalyzer : ExpressionAnalyzer {
@@ -5910,7 +5918,7 @@ struct MultiValueFlowAnalyzer : ValueFlowAnalyzer {
         // ProgramMemory pm = pms.get(endBlock->link()->next(), getProgramState());
         for (const auto& p:pm.values) {
             nonneg int varid = p.first;
-            if (!symboldatabase->isVarId(varid))
+            if (symboldatabase && !symboldatabase->isVarId(varid))
                 continue;
             ValueFlow::Value value = p.second;
             if (vars.count(varid) != 0)
@@ -6437,8 +6445,6 @@ static void valueFlowUninit(TokenList* tokenlist, SymbolDatabase* /*symbolDataba
     }
 }
 
-static bool isContainerSizeChanged(const Token* tok, const Settings* settings = nullptr, int depth = 20);
-
 static bool isContainerSizeChanged(nonneg int varId,
                                    const Token* start,
                                    const Token* end,

test/testvalueflow.cpp

@@ -2464,6 +2464,17 @@ private:
         ASSERT_EQUALS(false, testValueOfXKnown(code, 3U, 0));
         ASSERT_EQUALS(false, testValueOfXImpossible(code, 3U, 0));
         ASSERT_EQUALS(false, testValueOfXImpossible(code, 3U, 1));
+
+        code = "struct A {\n"
+               "    int i, j;\n"
+               "    int foo() {\n"
+               "        i = 1;\n"
+               "        j = 2;\n"
+               "        int x = i;\n"
+               "        return x;\n"
+               "    }\n"
+               "};\n";
+        ASSERT_EQUALS(true, testValueOfXKnown(code, 7U, 1));
     }
 
     void valueFlowAfterSwap()