Fix handling of PM_CONSTANT_PATH_NODE node in keyword arguments with ARGS_SPLAT

This was handled correctly in parse.y (NODE_COLON2), but not in
prism. This wasn't caught earlier, because I only added tests for
the optimized case and not the unoptimized case. Add tests for
the unoptimized case.

In code terms:

```ruby
m(*a, kw: lvar::X)     # Does not require allocation for *a
m(*a, kw: method()::X) # Requires allocation for *a
```

This commit fixes the second case when prism is used.

Author: jeremyevans

prism_compile.c

@@ -1855,7 +1855,6 @@ pm_setup_args_dup_rest_p(const pm_node_t *node)
     switch (PM_NODE_TYPE(node)) {
       case PM_BACK_REFERENCE_READ_NODE:
       case PM_CLASS_VARIABLE_READ_NODE:
-      case PM_CONSTANT_PATH_NODE:
       case PM_CONSTANT_READ_NODE:
       case PM_FALSE_NODE:
       case PM_FLOAT_NODE:
@@ -1874,6 +1873,13 @@ pm_setup_args_dup_rest_p(const pm_node_t *node)
       case PM_SYMBOL_NODE:
       case PM_TRUE_NODE:
         return false;
+      case PM_CONSTANT_PATH_NODE: {
+        const pm_constant_path_node_t *cast = (const pm_constant_path_node_t *) node;
+        if (cast->parent != NULL) {
+            return pm_setup_args_dup_rest_p(cast->parent);
+        }
+        return false;
+      }
       case PM_IMPLICIT_NODE:
         return pm_setup_args_dup_rest_p(((const pm_implicit_node_t *) node)->value);
       default:

test/ruby/test_allocation.rb

@@ -781,14 +781,16 @@ def self.r2k(*a#{block}); end
     def test_no_array_allocation_with_splat_and_nonstatic_keywords
       check_allocations(<<~RUBY)
         def self.keyword(a: nil, b: nil#{block}); end
+        def self.Object; Object end
 
         check_allocations(0, 1, "keyword(*nil, a: empty_array#{block})") # LVAR
         check_allocations(0, 1, "keyword(*empty_array, a: empty_array#{block})") # LVAR
         check_allocations(0, 1, "->{keyword(*empty_array, a: empty_array#{block})}.call") # DVAR
         check_allocations(0, 1, "$x = empty_array;  keyword(*empty_array, a: $x#{block})") # GVAR
         check_allocations(0, 1, "@x = empty_array; keyword(*empty_array, a: @x#{block})") # IVAR
         check_allocations(0, 1, "self.class.const_set(:X, empty_array); keyword(*empty_array, a: X#{block})") # CONST
-        check_allocations(0, 1, "keyword(*empty_array, a: Object::X#{block})") # COLON2
+        check_allocations(0, 1, "keyword(*empty_array, a: Object::X#{block})") # COLON2 - safe
+        check_allocations(1, 1, "keyword(*empty_array, a: Object()::X#{block})") # COLON2 - unsafe
         check_allocations(0, 1, "keyword(*empty_array, a: ::X#{block})") # COLON3
         check_allocations(0, 1, "T = self; #{'B = block' unless block.empty?}; class Object; @@x = X; T.keyword(*X, a: @@x#{', &B' unless block.empty?}) end") # CVAR
         check_allocations(0, 1, "keyword(*empty_array, a: empty_array, b: 1#{block})") # INTEGER
@@ -850,13 +852,15 @@ def test_no_array_allocation_with_splat_and_nonstatic_keywords
 
       check_allocations(<<~RUBY)
         keyword = keyword = proc{ |a: nil, b: nil #{block}| }
+        def self.Object; Object end
 
         check_allocations(0, 1, "keyword.(*empty_array, a: empty_array#{block})") # LVAR
         check_allocations(0, 1, "->{keyword.(*empty_array, a: empty_array#{block})}.call") # DVAR
         check_allocations(0, 1, "$x = empty_array;  keyword.(*empty_array, a: $x#{block})") # GVAR
         check_allocations(0, 1, "@x = empty_array; keyword.(*empty_array, a: @x#{block})") # IVAR
         check_allocations(0, 1, "self.class.const_set(:X, empty_array); keyword.(*empty_array, a: X#{block})") # CONST
-        check_allocations(0, 1, "keyword.(*empty_array, a: Object::X#{block})") # COLON2
+        check_allocations(0, 1, "keyword.(*empty_array, a: Object::X#{block})") # COLON2 - safe
+        check_allocations(1, 1, "keyword.(*empty_array, a: Object()::X#{block})") # COLON2 - unsafe
         check_allocations(0, 1, "keyword.(*empty_array, a: ::X#{block})") # COLON3
         check_allocations(0, 1, "T = keyword; #{'B = block' unless block.empty?}; class Object; @@x = X; T.(*X, a: @@x#{', &B' unless block.empty?}) end") # CVAR
         check_allocations(0, 1, "keyword.(*empty_array, a: empty_array, b: 1#{block})") # INTEGER