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Bug 368572

Summary:	[Xbase] Make type inference control flow aware
Product:	[Modeling] TMF	Reporter:	consiliens <consiliens>
Component:	Xtext	Assignee:	Project Inbox <tmf.xtext-inbox>
Status:	CLOSED FIXED	QA Contact:
Severity:	enhancement
Priority:	P3	CC:	sebastian.zarnekow, sven.efftinge
Version:	2.2.1	Flags:	sebastian.zarnekow: kepler+
Target Milestone:	M6
Hardware:	PC
OS:	Linux
Whiteboard:

Description consiliens @gmail.com

2012-01-13 12:30:49 EST

The following code should compile, however it generates invalid Java.

https://gist.github.com/1603753

Comment 1 Sven Efftinge

2012-01-17 03:03:58 EST

You need to provide type information during construction
E.g. 

val builder = ImmutableBiMap::<Integer, String>builder()

or ImmutableBiMapval<Integer, String> builder = ImmutableBiMap::builder()

If you don't do that "? extends Object" is inferred, which isn't compatible to your method definition.

I turn this into a feature enhancement about improving type inference along the control flow.

Comment 2 consiliens @gmail.com

2012-01-17 12:40:53 EST

> val builder = ImmutableBiMap::<Integer, String>builder()
This works.

> ImmutableBiMapval<Integer, String> builder = ImmutableBiMap::builder()
This doesn't work, even after removing val.  What's the proper syntax for specifying type parameters on the left hand side?

Comment 3 Sven Efftinge

2012-01-17 14:02:24 EST

Sorry, it's :

val ImmutableBiMapval<Integer, String> builder = ImmutableBiMap::builder()

Comment 4 consiliens @gmail.com

2012-01-17 14:26:45 EST

(In reply to comment #3)
> Sorry, it's :
> 
> val ImmutableBiMapval<Integer, String> builder = ImmutableBiMap::builder()

Still doesn't work.

// Incompatible types. Expected com.google.common.collect.ImmutableBiMap<java.lang.Integer,java.lang.String> 
// but was com.google.common.collect.ImmutableBiMap.Builder<K,V>	
val ImmutableBiMap<Integer, String> builder = ImmutableBiMap::builder()

I also tried:
import com.google.common.collect.ImmutableBiMap$Builder
// type cannot be derived
val ImmutableBiMap::Builder<Integer, String> builder = ImmutableBiMap::builder()

Comment 5 Sebastian Zarnekow

2013-04-19 05:11:44 EDT

Fixed in 2.4

Comment 6 Eclipse Webmaster

2017-10-31 11:25:37 EDT

Requested via bug 522520.

-M.