diff --git a/duchain/builders/declarationbuilder.h b/duchain/builders/declarationbuilder.h
--- a/duchain/builders/declarationbuilder.h
+++ b/duchain/builders/declarationbuilder.h
@@ -155,6 +155,7 @@
     QHash<qint64, FunctionDeclaration*> m_functions;
     QHash<qint64, NamespaceDeclaration*> m_namespaces;
     QList<KDevelop::QualifiedIdentifier> m_upcomingClassVariables;
+    unsigned int m_nonOptionalParametersLeft;
 
     /// handles common stuff for both interfaces and classes
     ClassDeclaration* openTypeDeclaration(IdentifierAst *name, KDevelop::ClassDeclarationData::ClassType type);
diff --git a/duchain/builders/declarationbuilder.cpp b/duchain/builders/declarationbuilder.cpp
--- a/duchain/builders/declarationbuilder.cpp
+++ b/duchain/builders/declarationbuilder.cpp
@@ -745,6 +745,32 @@
 {
     PushValue<ParameterAst*> push(m_functionDeclarationPreviousArgument, 0);
 
+    if (node->parametersSequence) {
+        //Find the correct number of optional parameters, since PHP allows default parameters even before non-optional arguments
+        //This messes up the DUChain, which is not built to handle such situations
+        unsigned int defaultParametersCount = 0;
+        auto it = node->parametersSequence->front();
+        forever {
+            if (it->element->defaultValue) {
+                //If it's a optional parameter, so increase the count
+                ++defaultParametersCount;
+            } else {
+                //Earlier optional parameters do not matter since this parameter is non-optional. Reset the count
+                defaultParametersCount = 0;
+            }
+
+            if (it->hasNext()) {
+                it = it->next;
+            } else {
+                break;
+            }
+        }
+
+        //Store the number of non-optional parameters
+        m_nonOptionalParametersLeft = node->parametersSequence->count() - defaultParametersCount;
+    } else {
+        m_nonOptionalParametersLeft = 0;
+    }
     DeclarationBuilderBase::visitParameterList(node);
 }
 
@@ -755,14 +781,16 @@
 
     if (node->defaultValue) {
         QString symbol = m_editor->parseSession()->symbol(node->defaultValue);
-        funDec->addDefaultParameter(IndexedString(symbol));
         if (node->isVariadic != -1) {
             reportError(i18n("Variadic parameter cannot have a default value"), node->defaultValue);
         } else if ( node->parameterType && node->parameterType->objectType && symbol.compare(QLatin1String("null"), Qt::CaseInsensitive) != 0 ) {
             reportError(i18n("Default value for parameters with a class type hint can only be NULL."), node->defaultValue);
         }
-    } else if ( !node->defaultValue && funDec->defaultParametersSize() ) {
-        reportError(i18n("Following parameters must have a default value assigned."), node);
+
+        //Only add the default value if there are no non-optional parameters still coming
+        if (!m_nonOptionalParametersLeft) {
+            funDec->addDefaultParameter(IndexedString(symbol));
+        }
     }
     {
         // create variable declaration for argument
@@ -782,6 +810,9 @@
     closeDeclaration();
 
     m_functionDeclarationPreviousArgument = node;
+    if (m_nonOptionalParametersLeft) {
+        --m_nonOptionalParametersLeft;
+    }
 }
 
 void DeclarationBuilder::visitFunctionDeclarationStatement(FunctionDeclarationStatementAst* node)
diff --git a/duchain/tests/duchain.h b/duchain/tests/duchain.h
--- a/duchain/tests/duchain.h
+++ b/duchain/tests/duchain.h
@@ -127,6 +127,7 @@
     void referencedArgument();
     void unsureReferencedArgument();
     void defaultArgument();
+    void defaultArgumentBeforeNonDefault();
     void declareMemberOutOfClass();
     void declareMemberOutOfClass2();
     void declareMemberInClassMethod();
diff --git a/duchain/tests/duchain.cpp b/duchain/tests/duchain.cpp
--- a/duchain/tests/duchain.cpp
+++ b/duchain/tests/duchain.cpp
@@ -2349,6 +2349,18 @@
     QCOMPARE(dec->type<IntegralType>()->dataType(), (uint)IntegralType::TypeInt);
 }
 
+void TestDUChain::defaultArgumentBeforeNonDefault()
+{
+    QByteArray code("<?php function foo($a = 1, $b) {} ");
+    TopDUContext* top = parse(code, DumpNone);
+    DUChainReleaser releaseTop(top);
+    DUChainWriteLocker lock(DUChain::lock());
+
+    AbstractFunctionDeclaration* dec = dynamic_cast<AbstractFunctionDeclaration*>(top->localDeclarations().at(0));
+    QVERIFY(dec);
+    QCOMPARE(dec->defaultParametersSize(), 0u);
+}
+
 void TestDUChain::declareMemberOutOfClass()
 {
     //               0         1         2         3         4         5         6         7