sferik · Oct 19, 2026
diff --git a/core/src/main/java/org/jruby/ir/instructions/IntegerMathInstr.java b/core/src/main/java/org/jruby/ir/instructions/IntegerMathInstr.java
@@ -47,6 +47,8 @@ public static IntegerMathInstr decode(IRReaderDecoder d) {
     @Override
     public void encode(IRWriterEncoder e) {
         super.encode(e);
+        e.encode(getOperand1());
+        e.encode(getOperand2());
         e.encode(op.ordinal());
     }
 

diff --git a/core/src/main/java/org/jruby/ir/operands/TemporaryLocalVariable.java b/core/src/main/java/org/jruby/ir/operands/TemporaryLocalVariable.java
@@ -90,6 +90,7 @@ public static TemporaryLocalVariable decode(IRReaderDecoder d) {
             case CURRENT_MODULE: return TemporaryCurrentModuleVariable.decode(d);
             case FLOAT: return TemporaryFloatVariable.decode(d);
             case FIXNUM: return TemporaryFixnumVariable.decode(d);
+            case INT: return TemporaryIntVariable.decode(d);
             case BOOLEAN: return TemporaryBooleanVariable.decode(d);
             case LOCAL: return d.getCurrentScope().getManager().newTemporaryLocalVariable(d.decodeInt());
         }

diff --git a/core/src/main/java/org/jruby/ir/persistence/IRReaderStream.java b/core/src/main/java/org/jruby/ir/persistence/IRReaderStream.java
@@ -252,8 +252,10 @@ public Instr decodeInstr() {
             case ALIAS: return AliasInstr.decode(this);
             case ARRAY_DEREF: return ArrayDerefInstr.decode(this);
             case ATTR_ASSIGN: return AttrAssignInstr.decode(this);
+            case AS_FIXNUM: return AsFixnumInstr.decode(this);
             case AS_STRING: return AsStringInstr.decode(this);
             case B_FALSE: return BFalseInstr.decode(this);
+            case B_INT: return BIntInstr.decode(this);
             case B_NIL: return BNilInstr.decode(this);
             case B_SWITCH: return BSwitchInstr.decode(this);
             case B_TRUE: return BTrueInstr.decode(this);
@@ -301,6 +303,7 @@ public Instr decodeInstr() {
             case GVAR_ALIAS: return GVarAliasInstr.decode(this);
             case INHERITANCE_SEARCH_CONST: return InheritanceSearchConstInstr.decode(this);
             case INSTANCE_SUPER: return InstanceSuperInstr.decode(this);
+            case INT_MATH: return IntegerMathInstr.decode(this);
             case JUMP: return JumpInstr.decode(this);
             case LABEL: return LabelInstr.decode(this);
             case LAMBDA: return BuildLambdaInstr.decode(this);

diff --git a/spec/compiler/general_spec.rb b/spec/compiler/general_spec.rb
@@ -964,6 +964,13 @@
       run("def foo; case 0; when 1; return 2 if self.nil?; end; return 3; end; foo") {|result| expect(result).to eq 3 }
     end
 
+    # See https://github.com/jruby/jruby/issues/9834
+    it "compiles array patterns" do
+      run('[([1] in [1]), ([1, 2] in [_, 2]), ([1, 2, 3] in [1, *r]) && r, (case [3]; in [x] then x; end)]') do |x|
+        expect(x).to eq [true, true, [2, 3], 3]
+      end
+    end
+
     it "assigns named groups in regular expressions to local variables" do
       # named groups with capture
       run("
@@ -1262,9 +1269,9 @@

    it "handles nested [], loops, and break" do
      run('def foo
             while 1
               "x"[0]
               while 1
                 raise "ok"
                 break
               end
@@ -1502,8 +1509,8 @@
    end

    it "calls struct field methods" do
      run('StructTest1 = Struct.new(:foo); st1 = StructTest1.new; st1.foo = 1; st1.foo') {|x| expect(x).to eq(1)}
      run('StructTest2 = Struct.new(:foo); class StructTest2; def do_foo; self.foo = 1; foo; end; end; StructTest2.new.do_foo') {|x| expect(x).to eq(1)}
    end

    it "calls aref with string key" do
@@ -1602,7 +1609,7 @@
    it "compiles debug chilled strings that can be modified without impacting other strings" do
      JRuby.runtime.instance_config.debugging_frozen_string_literal = true
      run(<<~CHILLED) {|val| expect(val).to eq("")}
        str = ""
        str << "hello"
        ""
      CHILLED