diff --git a/js/public/Value.h b/js/public/Value.h
index e21b104a80..30f4670049 100644
--- a/js/public/Value.h
+++ b/js/public/Value.h
@@ -1508,6 +1508,8 @@ DispatchTyped(F f, const JS::Value& val, Args&&... args)
         return f(&val.toObject(), mozilla::Forward<Args>(args)...);
     if (val.isSymbol())
         return f(val.toSymbol(), mozilla::Forward<Args>(args)...);
+    if (val.isBigInt())
+        return f(val.toBigInt(), mozilla::Forward<Args>(args)...);
     if (MOZ_UNLIKELY(val.isPrivateGCThing()))
         return DispatchTyped(f, val.toGCCellPtr(), mozilla::Forward<Args>(args)...);
     MOZ_ASSERT(!val.isGCThing());
diff --git a/js/src/jit/BaselineIC.cpp b/js/src/jit/BaselineIC.cpp
index 61d77adc2e..0a87121c6e 100644
--- a/js/src/jit/BaselineIC.cpp
+++ b/js/src/jit/BaselineIC.cpp
@@ -8093,6 +8093,9 @@ ICTypeOf_Typed::Compiler::generateStubCode(MacroAssembler& masm)
         masm.branchTestSymbol(Assembler::NotEqual, R0, &failure);
         break;
 
+      case JSTYPE_BIGINT:
+          return false;
+
       default:
         MOZ_CRASH("Unexpected type");
     }
diff --git a/js/src/vm/BigIntType.cpp b/js/src/vm/BigIntType.cpp
index d32489a8f6..6beed9af11 100644
--- a/js/src/vm/BigIntType.cpp
+++ b/js/src/vm/BigIntType.cpp
@@ -1778,7 +1778,7 @@ BigInt* BigInt::mod(ExclusiveContext* cx, HandleBigInt x, HandleBigInt y) {
       return nullptr;
     }
     MOZ_ASSERT(remainder);
-    return remainder;
+    return destructivelyTrimHighZeroDigits(cx, remainder);
   }
 }
 
@@ -2195,7 +2195,7 @@ uint64_t BigInt::toUint64(BigInt* x) {
 
   uint64_t digit = x->digit(0);
 
-  if (DigitBits == 32 && x->digitLength() >= 1) {
+  if (DigitBits == 32 && x->digitLength() > 1) {
     digit |= static_cast<uint64_t>(x->digit(1)) << 32;
   }