[GROOVY-9580] STC: return type checking for generic, covariant property gives false error

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.4, 2.5.12
• Fix Version/s: 4.0.0-alpha-1, 3.0.5, 2.5.13
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 31/May/20 15:16
• Updated: 23/Jul/20 14:16
• Resolved: 09/Jun/20 12:49

Description

Follow up to GROOVY-7691. When getter generated for property is used, return type check fails.

            import groovy.transform.*

            @CompileStatic
            @TupleConstructor(includeFields=true)
            abstract class A<N extends Number> {
                final N number
            }

            @CompileStatic
            class C<L extends Long> extends A<L> {
                C(L longNumber) {
                    super(longNumber)
                }

                L getValue() {
                    return getNumber() // property method stubbed by StaticTypeCheckingVisitor
                }
            }

            assert new C<Long>(42L).value == 42L

"[Static type checking] - Cannot return value of type N on method returning type L"

StaticTypeCheckingVisitor has set the wrong declaring class for getNumber and so generics resolution from N to Long fails.