@@ -1698,7 +1698,8 @@ public void DefineModuleInstr(DefineModuleInstr definemoduleinstr) {
 
     // 'when' statements emit a 1;1 use:def temporary which we can omit and just leave eqq result on the stack.
     private boolean canOmitStoreLoad(EQQInstr eqq, Instr nextInstr) {
-        assert nextInstr != null: "Somehow EQQ is the last instr in the scope...";
+        // nextInstr is null when the eqq ends its basic block, as each in clause's eqq does inside a block
+        if (nextInstr == null) return false;
 
         return !eqq.isPattern() && nextInstr instanceof BTrueInstr && eqq.getResult().equals(((BTrueInstr) nextInstr).getArg1());
     }
 
@@ -1216,6 +1216,13 @@ def foo(str: "bar", num: 45, **opts)
       end
     end
 
+    # See https://github.com/jruby/jruby/issues/9829
+    it "compiles a case/in with several in clauses inside a block" do
+      run('[0, 1, 2].map { |v| case v; in 0 then :zero; in 1 then :one; else :other; end }') do |x|
+        expect(x).to eq [:zero, :one, :other]
+      end
+    end
+
     it "enforces visibility" do
       run('obj = Class.new do
              def a; true; end
Original file line number	Diff line number	Diff line change
`@@ -1698,7 +1698,8 @@ public void DefineModuleInstr(DefineModuleInstr definemoduleinstr) {`
`1698`	`1698`
`1699`	`1699`	`// 'when' statements emit a 1;1 use:def temporary which we can omit and just leave eqq result on the stack.`
`1700`	`1700`	`private boolean canOmitStoreLoad(EQQInstr eqq, Instr nextInstr) {`
`1701`		`- assert nextInstr != null: "Somehow EQQ is the last instr in the scope...";`
	`1701`	`+ // nextInstr is null when the eqq ends its basic block, as each in clause's eqq does inside a block`
	`1702`	`+ if (nextInstr == null) return false;`
`1702`	`1703`
`1703`	`1704`	`return !eqq.isPattern() && nextInstr instanceof BTrueInstr && eqq.getResult().equals(((BTrueInstr) nextInstr).getArg1());`
`1704`	`1705`	`}`