Fix #12142 FP uninitStructMember, unreadVariable with pointer to member (#5618)

Author: chrchr-github

lib/checkuninitvar.cpp

@@ -697,6 +697,11 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
             return true;
         }
 
+        // bailout if there is a pointer to member
+        if (Token::Match(tok, "%varid% . *", var.declarationId())) {
+            return true;
+        }
+
         if (tok->str() == "?") {
             if (!tok->astOperand2())
                 return true;

lib/fwdanalysis.cpp

@@ -500,6 +500,8 @@ bool FwdAnalysis::possiblyAliased(const Token *expr, const Token *startToken) co
 {
     if (expr->isUnaryOp("*") && !expr->astOperand1()->isUnaryOp("&"))
         return true;
+    if (Token::simpleMatch(expr, ". *"))
+        return true;
 
     const bool macro = false;
     const bool pure = false;

test/testuninitvar.cpp

@@ -4875,6 +4875,15 @@ class TestUninitVar : public TestFixture {
                        "    return s;\n"
                        "}");
         ASSERT_EQUALS("", errout.str());
+
+        checkUninitVar("struct S { int i; };\n" // #12142
+                       "int f() {\n"
+                       "    S s;\n"
+                       "    int S::* p = &S::i;\n"
+                       "    s.*p = 123;\n"
+                       "    return s.i;\n"
+                       "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void uninitvar2_while() {

test/testunusedvar.cpp

@@ -201,6 +201,7 @@ class TestUnusedVar : public TestFixture {
         TEST_CASE(localvarStruct11); // 10095
         TEST_CASE(localvarStruct12); // #10495
         TEST_CASE(localvarStruct13); // #10398
+        TEST_CASE(localvarStruct14);
         TEST_CASE(localvarStructArray);
         TEST_CASE(localvarUnion1);
 
@@ -5330,6 +5331,17 @@ class TestUnusedVar : public TestFixture {
         ASSERT_EQUALS("", errout.str());
     }
 
+    void localvarStruct14() { // #12142
+        functionVariableUsage("struct S { int i; };\n"
+                              "int f() {\n"
+                              "    S s;\n"
+                              "    int S::* p = &S::i;\n"
+                              "    s.*p = 123;\n"
+                              "    return s.i;\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void localvarStructArray() {
         // extracttests.start: struct X {int a;};