@Incubating
class MonadicShapeChecker
extends TypeCheckingDSL

Compile-time lint for native monadic chains over the standard carrier allow-list (MonadicCarrierRegistry).

Sister to MonadicChecker: that one repairs erasure on calls routed through the DO macro's runtime dispatcher; this one catches shape bugs in hand-written flatMap/map (and thenCompose/thenApply/etc.) chains that the JDK generics cannot reject:

• bind returning a non-carrier — e.g. Optional.flatMap { it + 1 } where the JDK expects an Optional. STC can silently let closures pass this gap.
• bind returning a different carrier — e.g. Stream.flatMap { Optional.of(it) }. Almost certainly a bug.
• map returning the same carrier — e.g. Optional.map { Optional.of(it) } producing Optional<Optional<T>>; usually a missed flatMap (or thenCompose).

Two modes, selected via the extension option mode:

 // default (lenient): only flag high-confidence problems
 @TypeChecked(extensions = 'groovy.typecheckers.MonadicShapeChecker')

 // strict: also flag chains whose function return cannot be statically resolved
 @TypeChecked(extensions = "groovy.typecheckers.MonadicShapeChecker(mode: 'strict')")
 

Since:

6.0.0

See Also:

MonadicCarrierRegistry

MonadicChecker

Monadic