[PRISM] Fix LocalVariableWriteNodes within blocks

Prior to this commit, we weren't recursing up scopes to look for
the local definition. With this commit, we do so, fixing local writes
within blocks

prism_compile.c

@@ -685,6 +685,26 @@ pm_interpolated_node_compile(pm_node_list_t *parts, rb_iseq_t *iseq, NODE dummy_
     }
 }
 
+// This recurses through scopes and finds the local index at any scope leve
+static int
+pm_lookup_local_index_any_scope(rb_iseq_t *iseq, pm_scope_node_t *scope_node, pm_constant_id_t constant_id)
+{
+    if (!scope_node) {
+        // We have recursed up all scope nodes
+        // and have not found the local yet
+        rb_bug("This local does not exist");
+    }
+
+    st_data_t local_index;
+
+    if (!st_lookup(scope_node->index_lookup_table, constant_id, &local_index)) {
+        // Local does not exist at this level, continue recursing up
+        return pm_lookup_local_index_any_scope(iseq, scope_node->previous, constant_id);
+    }
+
+    return (int)scope_node->index_lookup_table->num_entries - (int)local_index;
+}
+
 static int
 pm_lookup_local_index(rb_iseq_t *iseq, pm_scope_node_t *scope_node, pm_constant_id_t constant_id)
 {
@@ -2866,7 +2886,7 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
         for (size_t index = 0; index < local_write_node->depth; index++) scope_node = scope_node->previous;
         int index = pm_lookup_local_index(iseq, scope_node, constant_id);
 
-        ADD_SETLOCAL(ret, &dummy_line_node, (int)index, local_write_node->depth);
+        ADD_SETLOCAL(ret, &dummy_line_node, index, local_write_node->depth);
         return;
       }
       case PM_LOCAL_VARIABLE_WRITE_NODE: {
@@ -2876,9 +2896,9 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
         PM_DUP_UNLESS_POPPED;
 
         pm_constant_id_t constant_id = local_write_node->name;
-        int index = pm_lookup_local_index(iseq, scope_node, constant_id);
+        int index = pm_lookup_local_index_any_scope(iseq, scope_node, constant_id);
 
-        ADD_SETLOCAL(ret, &dummy_line_node, (int)index, local_write_node->depth);
+        ADD_SETLOCAL(ret, &dummy_line_node, index, local_write_node->depth);
         return;
       }
       case PM_MATCH_LAST_LINE_NODE: {

test/ruby/test_compile_prism.rb

@@ -268,6 +268,28 @@ module Prism
 
     def test_LocalVariableWriteNode
       assert_prism_eval("pit = 1")
+      assert_prism_eval(<<-CODE)
+        a = 0
+        [].each do
+          a = 1
+        end
+        a
+      CODE
+
+      assert_prism_eval(<<-CODE)
+        a = 1
+        d = 1
+        [1].each do
+          b = 2
+          a = 2
+          [2].each do
+            c = 3
+            d = 4
+            a = 2
+          end
+        end
+        [a, d]
+      CODE
     end
 
     def test_MatchWriteNode