Fix #9761 FP constParameter on parameter assigned to boost::optional<T&> (#8548)

Co-authored-by: chrchr-github <noreply@github.com>

Author: chrchr-github

lib/astutils.cpp

@@ -3114,6 +3114,8 @@ static const Token* findExpressionChangedImpl(const Token* expr,
                     if (vt->type == ValueType::ITERATOR)
                         ++indirect;
                 }
+                if (indirect == 0 && tok2->astParent() && tok2->astParent()->isUnaryOp("*"))
+                    ++indirect;
                 for (int i = 0; i <= indirect; ++i) {
                     if (isExpressionChangedAt(tok, tok2, i, global, settings, depth))
                         return true;

lib/checkother.cpp

@@ -1769,9 +1769,13 @@ void CheckOther::checkConstVariable()
             //Is it the right side of an initialization of a non-const reference
             bool usedInAssignment = false;
             for (const Token* tok = var->nameToken(); tok != scope->bodyEnd && tok != nullptr; tok = tok->next()) {
-                if (Token::Match(tok, "& %var% = %varid%", var->declarationId())) {
-                    const Variable* refvar = tok->next()->variable();
-                    if (refvar && !refvar->isConst() && refvar->nameToken() == tok->next()) {
+                if (Token::Match(tok, "%name% = %varid%", var->declarationId())) {
+                    const Variable* refvar = tok->variable();
+                    if (tok->strAt(-1) == "&" && refvar && !refvar->isConst() && refvar->nameToken() == tok) {
+                        usedInAssignment = true;
+                        break;
+                    }
+                    if (!tok->valueType() || tok->valueType()->type == ValueType::Type::RECORD) {
                         usedInAssignment = true;
                         break;
                     }

test/testother.cpp

@@ -4120,6 +4120,27 @@ class TestOther : public TestFixture {
               "    std::string _s;\n"
               "};\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("void f(int& r) {\n" // #9761
+              "    o1 = r;\n"
+              "}\n"
+              "boost::optional<int&> o2;\n"
+              "void g(int& r) {\n"
+              "    o2 = r;\n"
+              "}\n"
+              "struct T {\n"
+              "    int* p;\n"
+              "    T& operator=(int& rhs) { p = &rhs; return *this; }\n"
+              "};\n"
+              "void h(T& t, int& r) {\n"
+              "    t = r;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
+
+        check("void f(std::optional<int>& o) {\n"
+              "    *o = 1;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
     }
 
     void constParameterCallback() {