A simple mechanism for type security across compilation units

A simple technique is described that detects structural-type clashes across compilation units with an arbitrarily high degree of confidence. The type of each external object is described in canonical form. A hash function compresses the description into a short code. If the code is embedded in a symbol-table name, then consistency can be checked by an ordinary linker. For distributed programs, run-time checking of message types can be performed with very little overhead