C++: resolved self-value reference for enum

Added support for resolving case:
enum E
{
  val1,
  val2 = val1, // val2-4 are not resolved
  val3,
  val4
};

Task-number: QTCREATORBUG-13932
Change-Id: I122c5eb0b0397d6c02bc3db0a5c1ea1c28c5c6e7
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/libs/3rdparty/cplusplus/Bind.cpp

@@ -510,6 +510,24 @@ void calculateConstantValue(const Symbol *symbol, EnumeratorDeclaration *e, Cont
     }
 }
 
+const StringLiteral *valueOfEnumerator(const Enum *e, const Identifier *value) {
+    const int enumMemberCount = e->memberCount();
+    for (int i = 0; i < enumMemberCount; ++i) {
+        const Symbol *member = e->memberAt(i);
+        if (const Declaration *decl = member->asDeclaration()) {
+            if (const EnumeratorDeclaration *enumDecl = decl->asEnumeratorDeclarator()) {
+                if (const Name *enumDeclName = enumDecl->name()) {
+                    if (const Identifier *enumDeclIdentifier = enumDeclName->identifier()) {
+                        if (enumDeclIdentifier->equalTo(value))
+                            return enumDecl->constantValue();
+                    }
+                }
+            }
+        }
+    }
+    return 0;
+}
+
 } // anonymous namespace
 
 void Bind::enumerator(EnumeratorAST *ast, Enum *symbol)
@@ -528,12 +546,21 @@ void Bind::enumerator(EnumeratorAST *ast, Enum *symbol)
         EnumeratorDeclaration *e = control()->newEnumeratorDeclaration(ast->identifier_token, name);
         e->setType(control()->integerType(IntegerType::Int)); // ### introduce IntegerType::Enumerator
 
-        if (ExpressionAST *expr = ast->expression)
+        if (ExpressionAST *expr = ast->expression) {
-            e->setConstantValue(asStringLiteral(expr->firstToken(), expr->lastToken()));
+            const int firstToken = expr->firstToken();
-        else if (!symbol->isEmpty())
+            const int lastToken = expr->lastToken();
+            const StringLiteral *constantValue = asStringLiteral(firstToken, lastToken);
+            const StringLiteral *resolvedValue = 0;
+            if (lastToken - firstToken == 1) {
+                if (const Identifier *constantId = identifier(firstToken))
+                    resolvedValue = valueOfEnumerator(symbol, constantId);
+            }
+            e->setConstantValue(resolvedValue ? resolvedValue : constantValue);
+        } else if (!symbol->isEmpty()) {
             calculateConstantValue(*(symbol->memberEnd()-1), e, control());
-        else
+        } else {
             e->setConstantValue(control()->stringLiteral("0", 1));
+        }
 
         symbol->addMember(e);
     }

tests/auto/cplusplus/semantic/tst_semantic.cpp

@@ -189,6 +189,7 @@ private slots:
     void enum_constantValue2();
     void enum_constantValue3();
     void enum_constantValue4();
+    void enum_constantValue5();
 };
 
 void tst_Semantic::function_declaration_1()
@@ -890,5 +891,30 @@ void tst_Semantic::enum_constantValue4()
     testEnumaratorDeclarator(e, 4, "11");
 }
 
+void tst_Semantic::enum_constantValue5()
+{
+    QSharedPointer<Document> doc = document("\n"
+                                            "enum {\n"
+                                            "E1,\n"
+                                            "E2=E1,\n"
+                                            "E3,\n"
+                                            "E4=E3,\n"
+                                            "E5\n"
+                                            "};\n"
+                                            );
+
+    QCOMPARE(doc->errorCount, 0U);
+    QCOMPARE(doc->globals->memberCount(), 1U);
+    Enum *e = doc->globals->memberAt(0)->asEnum();
+    QVERIFY(e);
+    QCOMPARE(e->memberCount(), 5U);
+
+    testEnumaratorDeclarator(e, 0, "0");
+    testEnumaratorDeclarator(e, 1, "0");
+    testEnumaratorDeclarator(e, 2, "1");
+    testEnumaratorDeclarator(e, 3, "1");
+    testEnumaratorDeclarator(e, 4, "2");
+}
+
 QTEST_MAIN(tst_Semantic)
 #include "tst_semantic.moc"