Scott Murphy Heiberg created GROOVY-12662:
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Summary: STC rejects an implicit-this call in a closure to an
overloaded Closure method, such as curry(x), as ambiguous, and ignores argument
types when choosing the Closure method
Key: GROOVY-12662
URL: https://issues.apache.org/jira/browse/GROOVY-12662
Project: Groovy
Issue Type: Bug
Affects Versions: 5.0.8, 4.0.33, 6.0.0, 7.0.0-alpha-1
Reporter: Scott Murphy Heiberg
{code:groovy}
@groovy.transform.TypeChecked // or @CompileStatic
def test() {
Closure<Object> c = { String a, String b -> b == null ? curry(a) : a + b }
((Closure) c('x', null))('y')
}
assert test() == 'xy'
{code}
*Actual:*
{noformat}
[Static type checking] - Reference to method is ambiguous. Cannot choose
between [groovy.lang.Closure<V> groovy.lang.Closure#curry(java.lang.Object[]),
groovy.lang.Closure<V> groovy.lang.Closure#curry(java.lang.Object)]
{noformat}
*Expected:* 'xy', as in dynamic Groovy, which calls curry(Object) on the
enclosing closure. rcurry, ncurry, trampoline(), andThenSelf(), composeSelf()
and leftShift(Closure) fail the same way.
The selection ignores argument types altogether. If the owner declares
memoize(String) or getDelegate(int), then memoize('x') or getDelegate(1) inside
a closure is bound to Closure.memoize() or Closure.getDelegate(). Under
@CompileStatic the closure's method is called. Under @TypeChecked the inferred
type is wrong, and the call fails with a GroovyCastException. Dynamic Groovy
calls the owner's method. Under DELEGATE_ONLY, ClosureMetaClass sends curry,
ncurry, rcurry, leftShift and rightShift to the delegate, but the type checker
binds them to the closure.
Cause: for an implicit-this call in a closure, StaticTypeCheckingVisitor takes
every Closure method of that name (GROOVY-11386) without choosing among them by
argument type, and never falls back to the delegate or owner when none of them
accepts the arguments.
Verified: 4.0.33 (ambiguity only), 5.0.8, 6.0.0 and master.
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