MOVE_CAST_ERROR — MOVE_CAST_ERROR dump: failed dynamic type cast

MOVE_CAST_ERROR fires when ABAP OO code attempts a downcast or interface cast with the ?= operator, or an explicit CAST( ) expression, and the object instance on the right-hand side does not implement the interface or is not an instance of the target class named on the left-hand side. Unlike a plain type mismatch on flat data, this is a reference-type compatibility failure evaluated at runtime because the compiler cannot verify polymorphic assignments statically. The exception raised is CX_SY_MOVE_CAST_ERROR, catchable in a TRY block, but when uncaught it terminates the program as this dump. It also occurs with dynamic data references created through RTTI when the target reference type declared does not match the runtime type of the object the reference points to.

If a BAdI implementation is the source, use SE19 to check which implementation is active for the filter values in the failing instance and confirm the implementing class actually satisfies the interface the caller expects; deactivating a wrongly-scoped custom implementation is often the fastest safe fix, but any change to which implementation is active in production requires a change request. If an interface was changed and one implementer not updated, the fix is a code change in the lagging class and needs a transport through the normal development pipeline, not a quick note in production. If the cause is a transport inconsistency between systems, this is a basis and transport management issue, not a code defect, resolve by re-transporting the missing dependent object rather than touching the code. If a downcast assumption is simply wrong, replace the blind cast with an IS INSTANCE OF check and branch logic, which is a development fix requiring testing of every code path that previously relied on the assumption holding.

The near-universal reflex is to wrap the offending CAST or ?= statement in a TRY block catching CX_SY_MOVE_CAST_ERROR and doing nothing, or logging and continuing. This stops the dump but the object that failed to cast is simply skipped, and downstream processing silently proceeds without it. In workflow, output determination, or BAdI dispatch chains this produces missing documents, missing approvals, or partial postings with no error visible to the business user, which surfaces days later as a data discrepancy far harder to diagnose than the original dump.

Enforce IS INSTANCE OF checks before any narrowing cast in generic or framework-facing code, particularly in BAdI implementations and factory patterns where the object source is configuration-driven rather than statically known. When an interface used by more than one implementer changes, treat every implementing class as part of the same change request and test them together. Keep dependent objects bundled in the same transport request as the interface or class they depend on so a partial transport cannot leave one system at a different version than another.

This is an ABAP development issue in nearly all cases; a functional consultant is involved only when the failing cast sits inside a BAdI implementation tied to a business configuration decision. The handover note should include the exact class and interface names from the dump analysis text, the filter or configuration values active for the failing instance, and whether the same cast succeeds in a different system, which tells the developer whether to look at code logic or transport state.

CX_SY_MOVE_CAST_ERROR is the exception class behind this dump and can be caught explicitly in TRY blocks as a deliberate design choice rather than left to terminate. Neighbouring reference-handling dumps include OBJECTS_OBJREF_NOT_ASSIGNED for dereferencing an unset object reference and MOVE_TO_LIT_NOTALLOWED for illegal literal assignment. Any uncaught exception of this class also appears generically as UNCAUGHT_EXCEPTION if the raising code path differs slightly from the standard runtime cast check.