Fixed #10058 (False positive: redundant assignment, there is break)

danmar · danmar · commit bcf6039558b0 · 2020-12-25T09:08:15.000+01:00
diff --git a/lib/astutils.cpp b/lib/astutils.cpp
@@ -2429,6 +2429,14 @@ struct FwdAnalysis::Result FwdAnalysis::checkRecursive(const Token *expr, const
                 return result1;
             if (mWhat == What::ValueFlow && result1.type == Result::Type::WRITE)
                 mValueFlowKnown = false;
+            if (mWhat == What::Reassign && result1.type == Result::Type::BREAK) {
+                const Token *scopeEndToken = findNextTokenFromBreak(result1.token);
+                if (scopeEndToken) {
+                    const Result &result2 = checkRecursive(expr, scopeEndToken->next(), endToken, exprVarIds, local, inInnerClass, depth);
+                    if (result2.type == Result::Type::BAILOUT)
+                        return result2;
+                }
+            }
             if (Token::simpleMatch(tok->linkAt(1), "} else {")) {
                 const Token *elseStart = tok->linkAt(1)->tokAt(2);
                 const Result &result2 = checkRecursive(expr, elseStart, elseStart->link(), exprVarIds, local, inInnerClass, depth);
diff --git a/test/testother.cpp b/test/testother.cpp
@@ -184,6 +184,7 @@ class TestOther : public TestFixture {
         TEST_CASE(redundantVarAssignment_pointer);
         TEST_CASE(redundantVarAssignment_pointer_parameter);
         TEST_CASE(redundantVarAssignment_array);
+        TEST_CASE(redundantVarAssignment_switch_break);
         TEST_CASE(redundantInitialization);
         TEST_CASE(redundantMemWrite);
 
@@ -7419,6 +7420,34 @@ class TestOther : public TestFixture {
         ASSERT_EQUALS("", errout.str());
     }
 
+    void redundantVarAssignment_switch_break() {
+        // #10058
+        check("void f(int a, int b) {\n"
+              "    int ret = 0;\n"
+              "    switch (a) {\n"
+              "    case 1:\n"
+              "        ret = 543;\n"
+              "        if (b) break;\n"
+              "        ret = 1;\n"
+              "        break;\n"
+              "    }"
+              "    return ret;\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f(int a, int b) {\n"
+              "    int ret = 0;\n"
+              "    switch (a) {\n"
+              "    case 1:\n"
+              "        ret = 543;\n"
+              "        if (b) break;\n"
+              "        ret = 1;\n"
+              "        break;\n"
+              "    }"
+              "}");
+        ASSERT_EQUALS("[test.cpp:5] -> [test.cpp:7]: (style) Variable 'ret' is reassigned a value before the old one has been used.\n", errout.str());
+    }
+
     void redundantInitialization() {
         setMultiline();
 
