patch 8.2.1817: Vim9: wrong instruction when reusing a local variable spotv8.2.1817

Problem:    Vim9: wrong instruction when reusing a local variable spot.
Solution:   Clear a newly allocated local variable. (closes #7080)

3 files changed, 29 insertions, 3 deletions

diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 28e503de7..608940290 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -2032,5 +2032,23 @@ def Test_callstack_def()
   endtry
 enddef
 
+" Re-using spot for variable used in block
+def Test_block_scoped_var()
+  var lines =<< trim END
+      vim9script
+      def Func()
+        var x = ['a', 'b', 'c']
+        if 1
+          var y = 'x'
+          map(x, {-> y})
+        endif
+        var z = x
+        assert_equal(['x', 'x', 'x'], z)
+      enddef
+      Func()
+  END
+  CheckScriptSuccess(lines)
+enddef
+
 
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
diff --git a/src/version.c b/src/version.c
index 598222ae6..5adfd9678 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1817,
+/**/
     1816,
 /**/
     1815,
diff --git a/src/vim9compile.c b/src/vim9compile.c
index a6bdcc3f3..74be262a5 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -1690,7 +1690,12 @@ generate_EXECCONCAT(cctx_T *cctx, int count)
  * Return the variable or NULL if it failed.
  */
     static lvar_T *
-reserve_local(cctx_T *cctx, char_u *name, size_t len, int isConst, type_T *type)
+reserve_local(
+	cctx_T	*cctx,
+	char_u	*name,
+	size_t	len,
+	int	isConst,
+	type_T	*type)
 {
     lvar_T  *lvar;
 
@@ -1703,6 +1708,7 @@ reserve_local(cctx_T *cctx, char_u *name, size_t len, int isConst, type_T *type)
     if (ga_grow(&cctx->ctx_locals, 1) == FAIL)
 	return NULL;
     lvar = ((lvar_T *)cctx->ctx_locals.ga_data) + cctx->ctx_locals.ga_len++;
+    CLEAR_POINTER(lvar);
 
     // Every local variable uses the next entry on the stack.  We could re-use
     // the last ones when leaving a scope, but then variables used in a closure
@@ -4438,7 +4444,6 @@ compile_nested_function(exarg_T *eap, cctx_T *cctx)
     char_u	*name_start = eap->arg;
     char_u	*name_end = to_name_end(eap->arg, TRUE);
     char_u	*lambda_name;
-    lvar_T	*lvar;
     ufunc_T	*ufunc;
     int		r;
 
@@ -4487,8 +4492,9 @@ compile_nested_function(exarg_T *eap, cctx_T *cctx)
     else
     {
 	// Define a local variable for the function reference.
-	lvar = reserve_local(cctx, name_start, name_end - name_start,
+	lvar_T	*lvar = reserve_local(cctx, name_start, name_end - name_start,
 						    TRUE, ufunc->uf_func_type);
+
 	if (lvar == NULL)
 	    return NULL;
 	if (generate_FUNCREF(cctx, ufunc) == FAIL)