[GROOVY-10372] STC: check lambda or closure parameter types against target method

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-rc-1
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 16/Nov/21 20:55
• Updated: 06/Jun/23 18:32
• Resolved: 17/Nov/21 16:04

Description

Follow up from GROOVY-10277. Consider the following:

@groovy.transform.TypeChecked
void test() {
  Comparator<Integer> cmp = (int one, int two) -> Integer.compare(one,two)
}

Instead of an error for mismatched generics – which was the previous disposition of the compiler – there could be an error for each typed parameter that does not match expectations. ecj produces the following error for the above's Java equivalent: "Lambda expression's parameter one is expected to be of type Integer"

These checks should extend to lambdas or closures that are cast, coerced or passed as arguments.

https://github.com/apache/groovy/blob/eb8854afcf02057f70b8a979a873e0a34393b740/src/test/groovy/transform/stc/LambdaTest.groovy#L243

Issue Links

• is related to: GROOVY-10277 STC fails to catch type error on the return type of lambdas
• is related to: GROOVY-9910 STC: no error for incorrect parameter type if not referenced in lambda