Modula-3
L. Cardelli et al, DEC and Olivetti, 1988. A descendant of Modula-2+ and Cedar, designed for safety and simplicity. Objects, generics, threads, exceptions and garbage collection. Modules are explicitly safe or unsafe. As in Mesa, any set of variables can be monitored. No multiple inheritance, no operator overloading. Uses structural equivalence. "Modula-3 Report", Luca Cardelli et al, TR 52, DEC SRC, and Olivetti Research Center, Aug 1988 (revised Oct 1989). The changes are described in "System Programming with Modula-3", Greg Nelson ed, P-H 1991, ISBN 0-13-590464-1. "Modula-3", Sam Harbison, P-H 1992. Version: SRC Modula-3 V1.5.
(ftp://gatekeeper.dec.com/pub/DEC/Modula-3/release/).
See also SRC Modula-3.