Fix #11139, #11817 FP unreadVariable (#5221)

danmar · Jul 7, 2023 · d6d3c7b · d6d3c7b
1 parent e73183a
commit d6d3c7b
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Showing 2 changed files with 38 additions and 0 deletions.
diff --git a/lib/fwdanalysis.cpp b/lib/fwdanalysis.cpp
@@ -364,6 +364,8 @@ struct FwdAnalysis::Result FwdAnalysis::checkRecursive(const Token *expr, const
             const Result &result1 = checkRecursive(expr, tok->tokAt(2), tok->linkAt(1), exprVarIds, local, inInnerClass, depth);
             if (result1.type == Result::Type::READ || result1.type == Result::Type::BAILOUT)
                 return result1;
+            if (mWhat == What::UnusedValue && result1.type == Result::Type::WRITE && expr->variable() && expr->variable()->isReference())
+                return result1;
             if (mWhat == What::ValueFlow && result1.type == Result::Type::WRITE)
                 mValueFlowKnown = false;
             if (mWhat == What::Reassign && result1.type == Result::Type::BREAK) {
@@ -530,6 +532,10 @@ bool FwdAnalysis::possiblyAliased(const Token *expr, const Token *startToken) co
             addrOf = tok->astOperand1();
         else if (Token::simpleMatch(tok, "std :: ref ("))
             addrOf = tok->tokAt(3)->astOperand2();
+        else if (tok->valueType() && tok->valueType()->pointer &&
+                 (Token::Match(tok, "%var% = %var% ;") || Token::Match(tok, "%var% {|( %var% }|)")) &&
+                 Token::Match(expr->previous(), "%varid% [", tok->tokAt(2)->varId()))
+            addrOf = tok->tokAt(2);
         else
             continue;
 

diff --git a/test/testunusedvar.cpp b/test/testunusedvar.cpp
@@ -165,6 +165,8 @@ class TestUnusedVar : public TestFixture {
         TEST_CASE(localvaralias19); // ticket #9828
         TEST_CASE(localvaralias20); // ticket #10966
         TEST_CASE(localvaralias21);
+        TEST_CASE(localvaralias22);
+        TEST_CASE(localvaralias23);
         TEST_CASE(localvarasm);
         TEST_CASE(localvarstatic);
         TEST_CASE(localvarextern);
@@ -5037,6 +5039,36 @@ class TestUnusedVar : public TestFixture {
         ASSERT_EQUALS("", errout.str());
     }
 
+    void localvaralias22() { // #11139
+        functionVariableUsage("int f() {\n"
+                              "    int x[1], *p = x;\n"
+                              "    x[0] = 42;\n"
+                              "    return *p;\n"
+                              "}\n"
+                              "int g() {\n"
+                              "    int x[1], *p{ x };\n"
+                              "    x[0] = 42;\n"
+                              "    return *p;\n"
+                              "}\n"
+                              "int h() {\n"
+                              "    int x[1], *p(x);\n"
+                              "    x[0] = 42;\n"
+                              "    return *p;\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
+    void localvaralias23() { // #11817
+        functionVariableUsage("void f(int& r, bool a, bool b) {\n"
+                              "    int& e = r;\n"
+                              "    if (a)\n"
+                              "        e = 42;\n"
+                              "    else if (b)\n"
+                              "        e = 1;\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void localvarasm() {
 
         functionVariableUsage("void foo(int &b)\n"