ASRA after moving to COBOL 6 - same program fine on 4.2

Online program compiled clean under COBOL 6.3, gets ASRA in CICS on first READ of a file it has used for years. Same source on the old 4.2 compiler was fine.

Offset points near a MOVE involving a REDEFINES. Wondering if alignment / unused data items changed under the new compiler and we are chasing a storage overlay.

Anyone hit ASRA specifically after a compiler upgrade?

Compare working-storage maps from both compiles. COBOL 6 is stricter about uninitialized stuff and can lay out storage differently. Also check SSRANGE if you turned it on with the upgrade.

We had an ASRA where a LINKAGE SECTION item was assumed to be addressable but the caller stopped passing it. Old compiler lucked out. Dump the KE at abend and confirm the base register.

Storage map diff found a REDEFINES that grew. Caller copybook was stale. Syncing copybooks fixed it.