diff --git a/duchain/helper.cpp b/duchain/helper.cpp
--- a/duchain/helper.cpp
+++ b/duchain/helper.cpp
@@ -446,6 +446,17 @@
         type = AbstractType::Ptr(new IntegralType(IntegralType::TypeInt));
     } else if (parameterType->stringType != -1) {
         type = AbstractType::Ptr(new IntegralType(IntegralType::TypeString));
+    } else if (parameterType->iterableType != -1) {
+        DeclarationPointer traversableDecl = findDeclarationImportHelper(currentContext, QualifiedIdentifier("traversable"), ClassDeclarationType);
+
+        if (traversableDecl) {
+            UnsureType::Ptr unsure(new UnsureType());
+            AbstractType::Ptr arrayType = AbstractType::Ptr(new IntegralType(IntegralType::TypeArray));
+            unsure->addType(arrayType->indexed());
+            unsure->addType(traversableDecl->abstractType()->indexed());
+
+            type = AbstractType::Ptr(unsure);
+        }
     }
 
     if (type && parameterType->isNullable != -1) {
diff --git a/duchain/tests/duchain.h b/duchain/tests/duchain.h
--- a/duchain/tests/duchain.h
+++ b/duchain/tests/duchain.h
@@ -41,12 +41,14 @@
     void declareTypehintVariadicFunction();
     void declareTypehintArrayFunction();
     void declareTypehintCallableFunction();
+    void declareTypehintIterableFunction();
     void declareTypehintBoolFunction();
     void declareTypehintFloatFunction();
     void declareTypehintIntFunction();
     void declareTypehintStringFunction();
     void declareNullableTypehintArrayFunction();
     void declareNullableTypehintCallableFunction();
+    void declareTypehintNullableIterableFunction();
     void declareTypehintWithPhpdocFunction();
     void returnTypeClass();
     void declarationReturnType();
diff --git a/duchain/tests/duchain.cpp b/duchain/tests/duchain.cpp
--- a/duchain/tests/duchain.cpp
+++ b/duchain/tests/duchain.cpp
@@ -706,6 +706,32 @@
     QVERIFY(type->dataType() == IntegralType::TypeMixed);
 }
 
+void TestDUChain::declareTypehintIterableFunction()
+{
+    //Note: in practice, Traversable is defined by php, but this interface is not loaded in this test, so define it ourselves
+    //                 0         1         2         3
+    //                 0123456789012345678901234567890123
+    QByteArray method("<? interface Traversable { } function foo(iterable $i) { } ");
+
+    TopDUContext* top = parse(method, DumpAll);
+    DUChainReleaser releaseTop(top);
+
+    DUChainWriteLocker lock(DUChain::lock());
+
+    QCOMPARE(top->localDeclarations().count(), 2);
+    FunctionType::Ptr fun = top->localDeclarations().at(1)->type<FunctionType>();
+    QVERIFY(fun);
+    QCOMPARE(fun->arguments().count(), 1);
+
+    UnsureType::Ptr argType = UnsureType::Ptr::dynamicCast(fun->arguments().first());
+    QVERIFY(argType);
+    QCOMPARE(argType->typesSize(), 2u);
+    QVERIFY(argType->types()[0].abstractType().cast<IntegralType>());
+    QVERIFY(argType->types()[0].abstractType().cast<IntegralType>()->dataType() == IntegralType::TypeArray);
+    QVERIFY(argType->types()[1].abstractType().cast<StructureType>());
+    QCOMPARE(argType->types()[1].abstractType().cast<StructureType>()->qualifiedIdentifier(), QualifiedIdentifier("traversable"));
+}
+
 void TestDUChain::declareTypehintBoolFunction()
 {
     //                 0         1         2         3
@@ -870,6 +896,34 @@
     QVERIFY(type->dataType() == IntegralType::TypeMixed);
 }
 
+void TestDUChain::declareTypehintNullableIterableFunction()
+{
+    //Note: in practice, Traversable is defined by php, but this interface is not loaded in this test, so define it ourselves
+    //                 0         1         2         3
+    //                 0123456789012345678901234567890123
+    QByteArray method("<? interface Traversable { } function foo(?iterable $i) { } ");
+
+    TopDUContext* top = parse(method, DumpAll);
+    DUChainReleaser releaseTop(top);
+
+    DUChainWriteLocker lock(DUChain::lock());
+
+    QCOMPARE(top->localDeclarations().count(), 2);
+    FunctionType::Ptr fun = top->localDeclarations().at(1)->type<FunctionType>();
+    QVERIFY(fun);
+    QCOMPARE(fun->arguments().count(), 1);
+
+    UnsureType::Ptr argType = UnsureType::Ptr::dynamicCast(fun->arguments().first());
+    QVERIFY(argType);
+    QCOMPARE(argType->typesSize(), 3u);
+    QVERIFY(argType->types()[0].abstractType().cast<IntegralType>());
+    QVERIFY(argType->types()[0].abstractType().cast<IntegralType>()->dataType() == IntegralType::TypeArray);
+    QVERIFY(argType->types()[1].abstractType().cast<StructureType>());
+    QCOMPARE(argType->types()[1].abstractType().cast<StructureType>()->qualifiedIdentifier(), QualifiedIdentifier("traversable"));
+    QVERIFY(argType->types()[2].abstractType().cast<IntegralType>());
+    QVERIFY(argType->types()[2].abstractType().cast<IntegralType>()->dataType() == IntegralType::TypeNull);
+}
+
 void TestDUChain::classImplementsInterface()
 {
     //                 0         1         2         3         4         5         6         7