This was Mantis bug #383.
compiler/ml_string_switch.m:
For model_non switches in MLDS grades, a failure is indicated by
a fall through. This can be represented by an empty sequence of
MLDS statements, but the code that generated string trie switches
took such an empty sequence to mean that the switch could not fail.
Fix this incorrect assumption.
tests/hard_coded/bug383.{m,inp,exp}:
A regression test for the bug.
tests/hard_coded/Mmakefile:
Enable the new test case.
