unit X deprecated 'msg'; — a unit hint directive is a parse error

• Type: compat (Pascal frontend, reference parity with FPC/Delphi) — Track P. Slug follows the compat-<lang>-* convention.
• Found: 2026-08-02, incidentally, while reaching Synapse's SSL units.

Measured

external/synapse/ssl_openssl.pas:2320 ends with the perfectly ordinary

unit ssl_openssl deprecated 'Use ssl_openssl3 with OpenSSL 3.0 instead';

and pxx stops on it:

pascal26:2320: error: unexpected token
  near: end  end  unit ssl_openssl >>> deprecated Use ssl_openssl3 with OpenSSL 3.0 instead

FPC and Delphi both accept hint directives on a unit declaration — deprecated (with or without a message string), platform, experimental, library, unimplemented. They are advisory: the unit still compiles, the compiler may emit a warning at the use site.

Impact — real but bounded

It is a hard parse error, so a unit carrying the directive cannot be compiled at all, and a deprecated unit is exactly the kind a real-world codebase keeps around for compatibility. It cost nothing here because ssl_openssl3 is the one to use on this box anyway; it would cost a lot on a project pinned to the older unit.

Not a silent-wrong-behaviour bug — it fails loudly and immediately, which is why this is compat rather than a bug- escalation.

Fix shape

Accept and ignore (or warn on) the hint-directive suffix on a unit declaration, and on the other declarations that take them (procedures, types, variables, class members) if those are not already handled — worth checking in the same pass rather than fixing one spelling.

Gate

unit X deprecated 'msg';, unit X deprecated;, unit X platform; and unit X experimental; all compile; a program using the unit still builds and runs. external/synapse/ssl_openssl.pas reaching the same wall the OpenSSL-3 unit does rather than a parse error is the real-world check.