--- a/js/src/jit/none/Lowering-none.h
+++ b/js/src/jit/none/Lowering-none.h
@@ -84,17 +84,17 @@ class LIRGeneratorNone : public LIRGener
     void visitAsmJSCompareExchangeHeap(MAsmJSCompareExchangeHeap *ins) { MOZ_CRASH(); }
     void visitAsmJSAtomicBinopHeap(MAsmJSAtomicBinopHeap *ins) { MOZ_CRASH(); }
 
     LTableSwitch *newLTableSwitch(LAllocation, LDefinition, MTableSwitch *) { MOZ_CRASH(); }
     LTableSwitchV *newLTableSwitchV(MTableSwitch *) { MOZ_CRASH(); }
     void visitSimdTernaryBitwise(MSimdTernaryBitwise *ins) { MOZ_CRASH(); }
     void visitSimdSplatX4(MSimdSplatX4 *ins) { MOZ_CRASH(); }
     void visitSimdValueX4(MSimdValueX4 *lir) { MOZ_CRASH(); }
-    bool visitSubstr(MSubstr *) { MOZ_CRASH(); }
+    void visitSubstr(MSubstr *) { MOZ_CRASH(); }
 
 };
 
 typedef LIRGeneratorNone LIRGeneratorSpecific;
 
 } // namespace jit
 } // namespace js