diff --git a/include/mruby/ops.h b/include/mruby/ops.h
index 9bb6f13ec..f8b91728b 100644
--- a/include/mruby/ops.h
+++ b/include/mruby/ops.h
@@ -57,7 +57,7 @@ OPCODE(JMPUW,      S)        /* unwind_and_jump_to(a) */
 OPCODE(EXCEPT,     B)        /* R[a] = exc */
 OPCODE(RESCUE,     BB)       /* R[b] = R[a].isa?(R[b]) */
 OPCODE(RAISEIF,    B)        /* raise(R[a]) if R[a] */
-OPCODE(MATCHERR,   Z)        /* raise NoMatchingPatternError */
+OPCODE(MATCHERR,   B)        /* raise NoMatchingPatternError unless R[a] */
 OPCODE(SSEND,      BBB)      /* R[a] = self.send(Syms[b],R[a+1]..,R[a+n+1]:R[a+n+2]..) (c=n|k<<4) */
 OPCODE(SSENDB,     BBB)      /* R[a] = self.send(Syms[b],R[a+1]..,R[a+n+1]:R[a+n+2]..,&R[a+n+2k+1]) */
 OPCODE(SEND,       BBB)      /* R[a] = R[a].send(Syms[b],R[a+1]..,R[a+n+1]:R[a+n+2]..) (c=n|k<<4) */
diff --git a/mrbgems/mruby-compiler/core/codegen.c b/mrbgems/mruby-compiler/core/codegen.c
index bd693d420..36a60b1d1 100644
--- a/mrbgems/mruby-compiler/core/codegen.c
+++ b/mrbgems/mruby-compiler/core/codegen.c
@@ -6625,14 +6625,24 @@ codegen(codegen_scope *s, node *tree, int val)
           }
         }
 
-        /* Optimize: single JMPNOT can be inverted to JMPIF, eliminating JMP */
+        /* Optimize: single JMPNOT can be replaced with MATCHERR for raise_on_fail */
         /* Conditions: (1) single entry in fail_pos chain,
          * (2) JMPNOT is immediately before current position (no code between), and
          * (3) the instruction is actually JMPNOT (not JMP from undefined pinned var) */
         if ((int32_t)(fail_pos + 2) + (int16_t)PEEK_S(s->iseq+fail_pos) == 0 &&
             fail_pos + 2 == s->pc &&
             s->iseq[fail_pos - 2] == OP_JMPNOT) {
-          /* Single failure point - invert JMPNOT to JMPIF */
+          if (mp->raise_on_fail) {
+            /* Single failure point with raise - replace JMPNOT with MATCHERR */
+            int reg = s->iseq[fail_pos - 1];  /* Register from JMPNOT */
+            s->pc = fail_pos - 2;  /* Rewind past JMPNOT */
+            s->lastpc = s->pc;
+            genop_1(s, OP_MATCHERR, reg);  /* Emit MATCHERR with the register */
+            s->sp = saved_sp - 1;
+            if (val) push();
+            break;  /* Pattern matching complete */
+          }
+          /* Single failure point with 'in' pattern - invert JMPNOT to JMPIF */
           s->iseq[fail_pos - 2] = OP_JMPIF;
           match_pos = fail_pos;
         }
@@ -6647,7 +6657,8 @@ codegen(codegen_scope *s, node *tree, int val)
         pop();  /* pop the value */
         if (mp->raise_on_fail) {
           /* expr => pattern: raise NoMatchingPatternError */
-          genop_0(s, OP_MATCHERR);
+          genop_1(s, OP_LOADF, cursp());  /* Load false for MATCHERR */
+          genop_1(s, OP_MATCHERR, cursp());
         }
         else {
           /* expr in pattern: return false */
diff --git a/src/codedump.c b/src/codedump.c
index d9d9ce80b..2bc3c9110 100644
--- a/src/codedump.c
+++ b/src/codedump.c
@@ -572,8 +572,8 @@ codedump(mrb_state *mrb, const mrb_irep *irep, FILE *out)
       fprintf(out, "RAISEIF\tR%d\t", a);
       print_lv_a(mrb, irep, a, out);
       break;
-    CASE(OP_MATCHERR, Z):
-      fprintf(out, "MATCHERR\n");
+    CASE(OP_MATCHERR, B):
+      fprintf(out, "MATCHERR\tR%d\n", a);
       break;
 
     CASE(OP_DEBUG, BBB):
diff --git a/src/vm.c b/src/vm.c
index 47231f187..21d5d3907 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -2167,8 +2167,11 @@ RETRY_TRY_BLOCK:
       NEXT;
     }
 
-    CASE(OP_MATCHERR, Z) {
-      RAISE_LIT(mrb, mrb_exc_get_id(mrb, MRB_ERROR_SYM(NoMatchingPatternError)), "pattern not matched");
+    CASE(OP_MATCHERR, B) {
+      if (!mrb_test(regs[a])) {
+        RAISE_LIT(mrb, mrb_exc_get_id(mrb, MRB_ERROR_SYM(NoMatchingPatternError)), "pattern not matched");
+      }
+      NEXT;
     }
 
     CASE(OP_SSEND, BBB) {