From: Mark <markjordanthom@gmail.com>
Date: Sun, 1 Oct 2023 04:22:01 +0000 (-0600)
Subject: throw instantiation_error from error/2 if Error_term uninstantiated (#2060)
X-Git-Tag: remove~61
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=4a8aa0acbdd9e9e17875f2c652385fb649dc7255;p=scryer-prolog.git

throw instantiation_error from error/2 if Error_term uninstantiated (#2060)
---

diff --git a/src/lib/builtins.pl b/src/lib/builtins.pl
index ec5a9968..b7b60df9 100644
--- a/src/lib/builtins.pl
+++ b/src/lib/builtins.pl
@@ -2226,4 +2226,7 @@ nl(Stream) :-
 %
 % Throws an exception of the following structure: `error(ErrorTerm, ImpDef)`.
 error(Error_term, Imp_def) :-
-   throw(error(Error_term, Imp_def)).
+    (  var(Error_term) ->
+       throw(error(instantiation_error, error/2))
+    ;  throw(error(Error_term, Imp_def))
+    ).