master 914f6b3c2c: * src/eval.c (Fdefvaralias): Clarify error messages. (Bug#56863)

[Eli Zaretskii]

branch: master
commit 914f6b3c2ce6c4147724b663bc9644c1fda01451
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    * src/eval.c (Fdefvaralias): Clarify error messages.  (Bug#56863)
---
 src/eval.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/eval.c b/src/eval.c
index 141d2546f0..d82d05797b 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -593,16 +593,19 @@ The return value is BASE-VARIABLE.  */)
 
   if (SYMBOL_CONSTANT_P (new_alias))
     /* Making it an alias effectively changes its value.  */
-    error ("Cannot make a constant an alias");
+    error ("Cannot make a constant an alias: %s",
+          SDATA (SYMBOL_NAME (new_alias)));
 
   sym = XSYMBOL (new_alias);
 
   switch (sym->u.s.redirect)
     {
     case SYMBOL_FORWARDED:
-      error ("Cannot make an internal variable an alias");
+      error ("Cannot make a built-in variable an alias: %s",
+            SDATA (SYMBOL_NAME (new_alias)));
     case SYMBOL_LOCALIZED:
-      error ("Don't know how to make a localized variable an alias");
+      error ("Don't know how to make a buffer-local variable an alias: %s",
+            SDATA (SYMBOL_NAME (new_alias)));
     case SYMBOL_PLAINVAL:
     case SYMBOL_VARALIAS:
       break;
@@ -633,7 +636,8 @@ The return value is BASE-VARIABLE.  */)
     for (p = specpdl_ptr; p > specpdl; )
       if ((--p)->kind >= SPECPDL_LET
          && (EQ (new_alias, specpdl_symbol (p))))
-       error ("Don't know how to make a let-bound variable an alias");
+       error ("Don't know how to make a let-bound variable an alias: %s",
+              SDATA (SYMBOL_NAME (new_alias)));
   }
 
   if (sym->u.s.trapped_write == SYMBOL_TRAPPED_WRITE)