Change Signature: Fix NPE on rendering empty parameter names

compiler/frontend/src/org/jetbrains/kotlin/psi/KtNamedDeclarationStub.java

@@ -90,7 +90,14 @@ abstract class KtNamedDeclarationStub<T extends KotlinStubWithFqName<?>> extends
             removeModifier(KtTokens.OPERATOR_KEYWORD);
         }
 
-        return identifier.replace(KtPsiFactory(this).createNameIdentifier(name));
+        PsiElement newIdentifier = KtPsiFactory(this).createNameIdentifierIfPossible(name);
+        if (newIdentifier != null) {
+            identifier.replace(newIdentifier);
+        }
+        else {
+            identifier.delete();
+        }
+        return this;
     }
 
     @Override

compiler/frontend/src/org/jetbrains/kotlin/psi/KtPsiFactory.kt

@@ -286,9 +286,9 @@ class KtPsiFactory @JvmOverloads constructor(private val project: Project, val m
         return declarations.first() as TDeclaration
     }
 
-    fun createNameIdentifier(name: String): PsiElement {
-        return createProperty(name, null, false).nameIdentifier!!
-    }
+    fun createNameIdentifier(name: String) = createNameIdentifierIfPossible(name)!!
+
+    fun createNameIdentifierIfPossible(name: String) = createProperty(name, null, false).nameIdentifier
 
     fun createSimpleName(name: String): KtSimpleNameExpression {
         return createProperty(name, null, false, name).initializer as KtSimpleNameExpression