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Bug 364618

Summary:	[Content Assist]: lookupCrossReference not working in empty documents
Product:	[Modeling] TMF	Reporter:	Reiner Hille <reiner.hille-doering>
Component:	Xtext	Assignee:	Project Inbox <tmf.xtext-inbox>
Status:	CLOSED WORKSFORME	QA Contact:
Severity:	normal
Priority:	P3	CC:	christian.dietrich.opensource, sebastian.zarnekow
Version:	2.0.0
Target Milestone:	---
Hardware:	PC
OS:	Windows 7
Whiteboard:

Description Reiner Hille

2011-11-23 11:30:34 EST

Repro:
-Create emptry project with following grammar:
==================================
grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.common.Terminals

generate myDsl "http://www.xtext.org/example/mydsl/MyDsl"

Script:
	(statements+=Statement)*;
	
Statement:
	(VariableDeclaration|VariableReference) ';'
;

VariableReference:
	var = [VariableDeclaration]
;


VariableDeclaration:
	"var" name=ID;
====================================
- Generate, run Target platform, create project.
- Create "file1.mydsl" with content 
==========
var v1;
==========
- Create "file2.mydsl" (empty).
- Press Ctrl-Space. The only proposal is "var".
- Type "v1;" -> File is valid
- Press Ctrl-Space again. Now proposal "v1" appears (beside "var").

Reason: 

Problem is that AbstractMyDslProposalProvider.completeVariableReference_Var() doesn't create proposals as long as the file is logically empty. At this point in time the root object "Script" has not yet been created. Therefore the parameter "model" is null. Therefore ReferenceProposalCreator.lookupCrossReference will not ask the (global) scope provider for possible references.

I would suggest to find a way that the root object of a grammar is initialized earlier and ideally is never null.

Comment 1 Sebastian Zarnekow

2011-11-25 11:25:35 EST

This behavior is expected if your root rule refuses to instantiate an element because everything is optional.

Please try 

Script:
    {Script} (statements+=Statement)*;

to force the parser to instantiate a model. Please reopen if the problem persists.

Comment 2 Karsten Thoms

2017-09-19 17:13:52 EDT

Closing all bugs that were set to RESOLVED before Neon.0

Comment 3 Karsten Thoms

2017-09-19 17:25:34 EDT

Closing all bugs that were set to RESOLVED before Neon.0