@let: bug re-using previously array-typed location as scalar.

* awkgram.y (let_var_list): We must generate the Op_clear_var
instruction even for variables which have initializers.
Otherwise the initialization will bomb if the initializer is
scalar, and the location we are re-using held an array previously.

* interpret.h (r_interpret): Do not use the get_lhs function,
which has complex semantics that depend on the existing type,
and may initialize the value, as well as blow up for an array.
We work directly with var->var_value. If var already has the
new variable type, we have nothing to do. We now unref the
prior value only if the prior type is Node_var, because prior
array values and such don't support unref.

* test/let1.awk: Extension of test case which reproduced this
problem, plus additional test cases for coverage of the duplicated
code in the Yacc grammar.

1 files changed, 9 insertions, 0 deletions

diff --git a/test/let1.awk b/test/let1.awk
index 431fb8b8..90b1248b 100644
--- a/test/let1.awk
+++ b/test/let1.awk
@@ -43,6 +43,15 @@ BEGIN {
 BEGIN {
    @let (i = 3) { }
    @let (a) { a[0] = 42 }
+   @let (i = 3) { }
+}
+
+# Yacc rules are duplicated for first versus rest, so we need additional coverage.
+
+BEGIN {
+   @let (x, i = 3) { }
+   @let (x, a) { a[0] = 42 }
+   @let (x, i = 3) { }
 }
 
 # test clearing uninitialized variables