"expected end of instruction" text parse error on invalid memory index

[kripken]

 (memory 1 1)

 (func $v128.load16_lane1 (param $0 i32) (param $1 v128) (result v128)
  (v128.load16_lane 1 0 ;; invalid memory index
   (local.get $0)
   (local.get $1)
  )
 )

$ bin/wasm-opt a.wat 
wasm-opt: src/parser/parsers.h:1008: MaybeResult<> wasm::WATParser::foldedinstr(Ctx &) [Ctx = wasm::WATParser::ParseDefsCtx]: Assertion `ctx.in.getPos() == *info.end && "expected end of instruction"' failed.
Aborted