@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.

3 files changed, 21 insertions, 0 deletions

diff --git a/symbol.c b/symbol.c
index 69f0a664..afa38f1b 100644
--- a/symbol.c
+++ b/symbol.c
@@ -433,6 +433,7 @@ install(const char *name, NODE *parm, NODETYPE type)
 	}
 
 	if (type == Node_param_list || type == Node_alias) {
+		r->dup_ent = NULL;
 		prev = in_array(table, n_name);
 		if (prev == NULL)
 			goto simple;
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 }
+}
diff --git a/test/let1.ok b/test/let1.ok
index 153d9d96..f3336775 100644
--- a/test/let1.ok
+++ b/test/let1.ok
@@ -3,3 +3,9 @@ gawk: let1.awk:9: warning: function `f0' called with more arguments than declare
 f1 3
 f2 3-8
 b3 3-8
+f5 1
+f5 1 2
+f5 1 2 3
+b6 1
+b6 1 2
+b6 1 2 3