[GROOVY-5924] Provide a mechanism to allow the type checker to know what are the expected argument types of a closure

• Type: Improvement
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 2.3.0-beta-1
• Component/s: Static Type Checker
• Assignee: Cédric Champeau
• Reporter: Cédric Champeau
• Created: 17/Jan/13 08:18
• Updated: 07/Nov/23 17:20
• Resolved: 15/Jan/14 11:16

Description

For methods like each, collect, times, ... that take a closure as an argument, the type checker doesn't have enough type information to infer what is the expected argument types of the closure. For example, in the following case:

List<String> strings = ['abc','def']
strings.collect { it.toUpperCase() }

there's not enough type information in the signature of collect for the type checker to know that the type of it is a String.

With the upcoming lambda support in JDK8, it becomes critical for us to provide such information.

Issue Links

• is depended upon by: GROOVY-5923 CompileStatic: closure dispatch is sometimes not type checked
• is depended upon by: GROOVY-5842 Runtimer error when types down match with Map and Map.Entry when using @CompileStatic
• is depended upon by: GROOVY-5899 withObject[Output|Input]Stream - auto detect 'it' type
• is depended upon by: GROOVY-6486 Type inference fails in @CompileStatic for collection iteration closure argument
• is depended upon by: GROOVY-6479 Closure to SAM interface coercion doesn't handle contravariant types correctly
• relates to: GROOVY-7934 Type inference breaks for Collection.inject

Sub-Tasks

• CompileStatic: closure dispatch is sometimes not type checked: Closed