Fix #14637: FP unassignedVariable with reference to array (#8441)

Author: ludviggunne

lib/checkunusedvar.cpp

@@ -565,7 +565,7 @@ static const Token* doAssignment(Variables &variables, const Token *tok, bool de
                             variables.readAll(varid2, tok);
                         }
                     }
-                } else if (var1->mType == Variables::reference) {
+                } else if (var1->mType == Variables::reference || var1->mType == Variables::referenceArray) {
                     variables.alias(varid1, varid2, true);
                 } else if (var1->mType == Variables::standard && addressOf) {
                     variables.alias(varid1, varid2, true);
@@ -738,6 +738,8 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
             if (type == Variables::none || isPartOfClassStructUnion(i->typeStartToken()))
                 continue;
             const Token* defValTok = i->nameToken()->next();
+            if (Token::Match(i->nameToken()->previous(), "& %var% )"))
+                defValTok = defValTok->next();
             while (defValTok && defValTok->str() == "[")
                 defValTok = defValTok->link()->next();
             if (Token::simpleMatch(defValTok, ") ("))

test/testunusedvar.cpp

@@ -198,6 +198,7 @@ class TestUnusedVar : public TestFixture {
         TEST_CASE(localvarreturn); // ticket #9167
         TEST_CASE(localvarmaybeunused);
         TEST_CASE(localvarrvalue); // ticket #13977
+        TEST_CASE(localvarreferencearray); // ticket #14637
 
         TEST_CASE(localvarthrow); // ticket #3687
 
@@ -6558,6 +6559,16 @@ class TestUnusedVar : public TestFixture {
         ASSERT_EQUALS("[test.cpp:3:21]: (style) Variable 'm' is assigned a value that is never used. [unreadVariable]\n", errout_str());
     }
 
+    void localvarreferencearray() { // ticket #14637
+        functionVariableUsage("int f() {\n"
+                              "        int a[1];\n"
+                              "        int(&r)[1] = a;\n"
+                              "        r[0] = 0;\n"
+                              "        return r[0];\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void localvarthrow() { // ticket #3687
         functionVariableUsage("void foo() {\n"
                               "    try {}"