Harbour reserves the aliases `M` and `MEMVAR` for the memvar
namespace — `M->cVar` reads a PUBLIC/PRIVATE memvar, not a DBF
field in a workarea named M. Five's emitAliasExpr and emitAssign
treated all aliases identically, emitting:
t.PushAliasField("M", "cVar") // read
_wa := t.WA.(*hbrdd.WorkAreaManager); _wa.SetAliasField("M", ...) // write
which triggered a spurious hbrdd import on programs using memvars
and attempted a workarea lookup that couldn't find a "M" area at
runtime.
Detect the reserved aliases (case-insensitive) at the three
AliasExpr call sites — the read path (emitAliasExpr) and both
assign paths (emitAssign for statements, emitAssignExpr for
expression context) — and route to t.PushMemvar / t.PopMemvar
instead. The existing Thread helpers hash into the MemvarTable
populated by PUBLIC/PRIVATE declarations.
Unblocks harbour-core/tests/macro.prg build (runtime still needs
the TVALUE test helper, unrelated). FiveSql2 43/43, Harbour compat
56/56, Go test ALL PASS.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>