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https://issues.apache.org/jira/browse/GROOVY-12105?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Paul King updated GROOVY-12105:
-------------------------------
Description:
Inside a trait STATIC method, an unqualified `super.m(...)` call does
not walk the trait chain documented for the instance-method case
(GEP-22 § "this, super, and stackable traits" item 2). The call
compiles successfully but throws MissingMethodException at runtime.
Minimal reproducer:
{code:groovy}
trait Base { static String m() { 'Base' } }
trait V extends Base {
static String m() { 'V' }
static callSuper() { super.m() } // unqualified, from static
}
class Impl implements V { }
Impl.callSuper()
{code}
Expected: either resolve to Base.m (matching the spec's "walks the
trait chain" semantic for the instance case) or reject at compile
time as an unsupported construct.
Actual (consistent across 4.0.32, 5.0.6, 6.0.0-alpha-1):
java.lang.MissingMethodException: No signature of method:
static Base.m() is applicable for argument types: () values: []
Contrast: the instance-method version of the same shape
(without `static`) works as the spec documents — returns 'Base'.
Plain Java/Groovy `super.m()` for class statics works normally
(returns the parent class's m()), so the limitation is specific to
trait static methods.
*Recommended fix*: either implement the trait-chain walk for statics
(symmetric with the instance-method case), or reject at compile time
with a clear error pointing to `T.super.m(...)` as the explicit form.
The latter is simpler and matches the recommendation in the GEP-22 v5
draft (§ "this, super, and stackable traits" item 4, already drafted
as part of the GEP-22 PR companion to this ticket).
*Test coverage*: row 15 in
src/test/groovy/org/codehaus/groovy/transform/traitx/TraitStaticDispatchMatrix.groovy
is currently @NotYetImplemented asserting the compile-error
end-state; will flip red when this ticket is resolved.
*Related*: GROOVY-11985, GROOVY-12093, JIRA #1 (T.this in trait body).
Both surfaced during empirical sweep for Grails alternatives.
> Unqualified super.m(...) from a static trait method throws
> MissingMethodException — should be a compile error or walk the trait chain
> -------------------------------------------------------------------------------------------------------------------------------------
>
> Key: GROOVY-12105
> URL: https://issues.apache.org/jira/browse/GROOVY-12105
> Project: Groovy
> Issue Type: Bug
> Reporter: Paul King
> Priority: Major
>
> Inside a trait STATIC method, an unqualified `super.m(...)` call does
> not walk the trait chain documented for the instance-method case
> (GEP-22 § "this, super, and stackable traits" item 2). The call
> compiles successfully but throws MissingMethodException at runtime.
> Minimal reproducer:
> {code:groovy}
> trait Base { static String m() { 'Base' } }
> trait V extends Base {
> static String m() { 'V' }
> static callSuper() { super.m() } // unqualified, from static
> }
> class Impl implements V { }
> Impl.callSuper()
> {code}
> Expected: either resolve to Base.m (matching the spec's "walks the
> trait chain" semantic for the instance case) or reject at compile
> time as an unsupported construct.
> Actual (consistent across 4.0.32, 5.0.6, 6.0.0-alpha-1):
> java.lang.MissingMethodException: No signature of method:
> static Base.m() is applicable for argument types: () values: []
> Contrast: the instance-method version of the same shape
> (without `static`) works as the spec documents — returns 'Base'.
> Plain Java/Groovy `super.m()` for class statics works normally
> (returns the parent class's m()), so the limitation is specific to
> trait static methods.
> *Recommended fix*: either implement the trait-chain walk for statics
> (symmetric with the instance-method case), or reject at compile time
> with a clear error pointing to `T.super.m(...)` as the explicit form.
> The latter is simpler and matches the recommendation in the GEP-22 v5
> draft (§ "this, super, and stackable traits" item 4, already drafted
> as part of the GEP-22 PR companion to this ticket).
> *Test coverage*: row 15 in
> src/test/groovy/org/codehaus/groovy/transform/traitx/TraitStaticDispatchMatrix.groovy
> is currently @NotYetImplemented asserting the compile-error
> end-state; will flip red when this ticket is resolved.
> *Related*: GROOVY-11985, GROOVY-12093, JIRA #1 (T.this in trait body).
> Both surfaced during empirical sweep for Grails alternatives.
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