Have cant_happen() give more information.

1 files changed, 3 insertions, 3 deletions

diff --git a/mpfr.c b/mpfr.c
index 25b7b467..dbaacb5c 100644
--- a/mpfr.c
+++ b/mpfr.c
@@ -496,7 +496,7 @@ mpg_update_var(NODE *n)
 		nr = FNR;
 		nq = MFNR;
 	} else
-		cant_happen();
+		cant_happen("invalid node for mpg_update_var%s", "");
 
 	if (mpz_sgn(nq) == 0) {
 		/* Efficiency hack similar to that for AWKNUM */
@@ -528,7 +528,7 @@ mpg_set_var(NODE *n)
 	else if (n == FNR_node)
 		nq = MFNR;
 	else
-		cant_happen();
+		cant_happen("invalid node for mpg_set_var%s", "");
 
 	if (is_mpg_integer(val))
 		r = val->mpg_i;
@@ -1847,7 +1847,7 @@ mod:
 			r = mpg_pow(t1, t2);
 			break;
 		default:
-			cant_happen();
+			cant_happen("unexpected opcode %s", opcode2str(op));
 		}
 
 		DEREF(t2);