Support NODE_ONCE for pattern matching

compile.c

@@ -7259,6 +7259,7 @@ iseq_compile_pattern_each(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *c
       case NODE_COLON3:
       case NODE_BEGIN:
       case NODE_BLOCK:
+      case NODE_ONCE:
         CHECK(COMPILE(ret, "case in literal", node)); // (1)
         if (in_single_pattern) {
             ADD_INSN1(ret, line_node, dupn, INT2FIX(2));

test/ruby/test_pattern_matching.rb

@@ -353,6 +353,14 @@ END
       end
     end
 
+    assert_block do
+      a = "abc"
+      case 'abc'
+      in /#{a}/o
+        true
+      end
+    end
+
     assert_block do
       case 0
       in ->(i) { i == 0 }