[PRISM] Properly compile MultiTargetNodes within parameters

If there are MultiTargetNodes within parameters, we need to
iterate over them and compile them individually correctly, once
the locals are all in the correct spaces. We need to add one
getlocal for the hidden variable, and then can recurse into the
MultiTargetNodes themselves

prism_compile.c

@@ -3709,6 +3709,13 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
         PM_POP_IF_POPPED;
         return;
       }
+      case PM_REQUIRED_PARAMETER_NODE: {
+        pm_required_parameter_node_t *required_parameter_node = (pm_required_parameter_node_t *)node;
+        int index = pm_lookup_local_index(iseq, scope_node, required_parameter_node->name);
+
+        ADD_SETLOCAL(ret, &dummy_line_node, index, 0);
+        return;
+      }
       case PM_MULTI_TARGET_NODE: {
         pm_multi_target_node_t *cast = (pm_multi_target_node_t *) node;
         bool has_rest_expression = (cast->rest &&
@@ -3723,17 +3730,22 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
             }
         }
 
+        if (has_rest_expression) {
+            if (cast->rights.size) {
+                ADD_INSN2(ret, &dummy_line_node, expandarray, INT2FIX(cast->rights.size), INT2FIX(3));
+            }
+            pm_node_t *expression = ((pm_splat_node_t *)cast->rest)->expression;
+            PM_COMPILE_NOT_POPPED(expression);
+        }
+
         if (cast->rights.size) {
-            ADD_INSN2(ret, &dummy_line_node, expandarray, INT2FIX(cast->rights.size), INT2FIX(2));
+            if (!has_rest_expression) {
+                ADD_INSN2(ret, &dummy_line_node, expandarray, INT2FIX(cast->rights.size), INT2FIX(2));
+            }
             for (size_t index = 0; index < cast->rights.size; index++) {
                 PM_COMPILE_NOT_POPPED(cast->rights.nodes[index]);
             }
         }
-
-        if (has_rest_expression) {
-            pm_node_t *expression = ((pm_splat_node_t *)cast->rest)->expression;
-            PM_COMPILE_NOT_POPPED(expression);
-        }
         return;
       }
       case PM_MULTI_WRITE_NODE: {
@@ -4368,6 +4380,11 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
         // those anonymous items temporary names (as below)
         int local_index = 0;
 
+        // We will assign these values now, if applicable, and use them for
+        // the ISEQs on these multis
+        int required_multis_hidden_index = 0;
+        int post_multis_hidden_index = 0;
+
         // Here we figure out local table indices and insert them in to the
         // index lookup table and local tables.
         //
@@ -4384,6 +4401,7 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
                   // def foo(a, (b, *c, d), e = 1, *f, g, (h, *i, j),  k:, l: 1, **m, &n)
                   //            ^^^^^^^^^^
                   case PM_MULTI_TARGET_NODE: {
+                      required_multis_hidden_index = local_index;
                       local = rb_make_temporary_id(local_index);
                       local_table_for_iseq->ids[local_index] = local;
                       break;
@@ -4453,6 +4471,7 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
                   // def foo(a, (b, *c, d), e = 1, *f, g, (h, *i, j),  k:, l: 1, **m, &n)
                   //                                      ^^^^^^^^^^
                   case PM_MULTI_TARGET_NODE: {
+                      post_multis_hidden_index = local_index;
                       local = rb_make_temporary_id(local_index);
                       local_table_for_iseq->ids[local_index] = local;
                       break;
@@ -4638,6 +4657,7 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
         // Goal: fill in the names of the parameters in MultiTargetNodes
         //
         // Go through requireds again to set the multis
+
         if (requireds_list && requireds_list->size) {
             for (size_t i = 0; i < requireds_list->size; i++) {
                 // For each MultiTargetNode, we're going to have one
@@ -4757,6 +4777,32 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
             body->param.opt_table = (const VALUE *)opt_table;
         }
 
+        if (requireds_list && requireds_list->size) {
+            for (size_t i = 0; i < requireds_list->size; i++) {
+                // For each MultiTargetNode, we're going to have one
+                // additional anonymous local not represented in the locals table
+                // We want to account for this in our table size
+                pm_node_t *required = requireds_list->nodes[i];
+                if (PM_NODE_TYPE_P(required, PM_MULTI_TARGET_NODE)) {
+                    ADD_GETLOCAL(ret, &dummy_line_node, table_size - required_multis_hidden_index, 0);
+                    PM_COMPILE(required);
+                }
+            }
+        }
+
+        if (posts_list && posts_list->size) {
+            for (size_t i = 0; i < posts_list->size; i++) {
+                // For each MultiTargetNode, we're going to have one
+                // additional anonymous local not represented in the locals table
+                // We want to account for this in our table size
+                pm_node_t *post = posts_list->nodes[i];
+                if (PM_NODE_TYPE_P(post, PM_MULTI_TARGET_NODE)) {
+                    ADD_GETLOCAL(ret, &dummy_line_node, table_size - post_multis_hidden_index, 0);
+                    PM_COMPILE(post);
+                }
+            }
+        }
+
         switch (body->type) {
           case ISEQ_TYPE_BLOCK: {
             LABEL *start = ISEQ_COMPILE_DATA(iseq)->start_label = NEW_LABEL(0);

test/ruby/test_compile_prism.rb

@@ -505,6 +505,7 @@ module Prism
       assert_prism_eval("a, (b, *c) = [1, [2, 3]]; c")
       assert_prism_eval("a, (b, *c) = 1, [2, 3]; c")
       assert_prism_eval("a, (b, *) = 1, [2, 3]; b")
+      assert_prism_eval("a, (b, *c, d) = 1, [2, 3, 4]; [a, b, c, d]")
       assert_prism_eval("(a, (b, c, d, e), f, g), h = [1, [2, 3]], 4, 5, [6, 7]; c")
     end
 
@@ -1175,12 +1176,58 @@ module Prism
       assert_prism_eval("class PrismTestDefNode; def prism_test_def_node(*a) a end end;  PrismTestDefNode.new.prism_test_def_node(1).inspect")
 
       # block argument
-      assert_prism_eval(<<-CODE
-                        def self.prism_test_def_node(&block) prism_test_def_node2(&block) end
-                        def self.prism_test_def_node2() yield 1 end
-                        prism_test_def_node2 {|a| a }
-                        CODE
-                       )
+      assert_prism_eval(<<-CODE)
+        def self.prism_test_def_node(&block) prism_test_def_node2(&block) end
+        def self.prism_test_def_node2() yield 1 end
+        prism_test_def_node2 {|a| a }
+      CODE
+
+      # multi argument
+      assert_prism_eval(<<-CODE)
+        def self.prism_test_def_node(a, (b, *c, d))
+          [a, b, c, d]
+        end
+        prism_test_def_node("a", ["b", "c", "d"])
+      CODE
+      assert_prism_eval(<<-CODE)
+        def self.prism_test_def_node(a, (b, c, *))
+          [a, b, c]
+        end
+        prism_test_def_node("a", ["b", "c"])
+      CODE
+      assert_prism_eval(<<-CODE)
+        def self.prism_test_def_node(a, (*, b, c))
+          [a, b, c]
+        end
+        prism_test_def_node("a", ["b", "c"])
+      CODE
+
+      # recursive multis
+      assert_prism_eval(<<-CODE)
+        def self.prism_test_def_node(a, (b, *c, (d, *e, f)))
+          [a, b, c, d, d, e, f]
+        end
+        prism_test_def_node("a", ["b", "c", ["d", "e", "f"]])
+      CODE
+
+      # Many arguments
+      assert_prism_eval(<<-CODE)
+        def self.prism_test_def_node(a, (b, *c, d), e = 1, *f, g, (h, *i, j),  k:, l: 1, **m)
+          [a, b, c, d, e, f, g, h, i, j, k, l, m]
+        end
+        prism_test_def_node(
+          "a",
+          ["b", "c1", "c2", "d"],
+          "e",
+          "f1", "f2",
+          "g",
+          ["h", "i1", "i2", "j"],
+          k: "k",
+          l: "l",
+          m1: "m1",
+          m2: "m2"
+        )
+      CODE
     end
 
     def test_method_parameters