@let: bugfix: must clear dup_ent of re-used symbol.

* symbol.c (install): If parm is a recycled node coming from the
parser's let_free or let_gfree stack, it might have non-null
dup_ent. We must clear that, otherwise if we install that node
as a new entry, it will look like it has ghost duplicate list,
corrupting the variable allocation algorithm.

* test/let1.awk, test/let1.ok: Add tests, which broke.

1 files changed, 14 insertions, 0 deletions

diff --git a/test/let1.awk b/test/let1.awk
index a67e3639..413b6e1e 100644
--- a/test/let1.awk
+++ b/test/let1.awk
@@ -143,3 +143,17 @@ BEGIN {
       exit 1
   }
 }
+
+function f5()
+{
+  @let (x = 1) { print "f5", x }
+  @let (x = 1, y = 2) { print "f5", x, y }
+  @let (x = 1, y = 2, z = 3) { print "f5", x, y, z }
+}
+
+BEGIN {
+  f5()
+  @let (x = 1) { print "b6", x }
+  @let (x = 1, y = 2) { print "b6", x, y }
+  @let (x = 1, y = 2, z = 3) { print "b6", x, y, z }
+}