wat2wasm aborts when function has undefined reference type in parameter

The following module

(module
  (func (param (ref $T)) (result)
    (nop)))

aborts in both the current main HEAD and the most recent package version on Ubuntu 20.04:

pat@quercus:~/src/crack$ ../wabt/bin/wat2wasm --version
1.0.31 (git~1.0.31-22-ged0b720c)

pat@quercus:~/src/crack$ ../wabt/bin/wat2wasm --enable-function-references scratch.wat -o scratch.wasm
wat2wasm: /home/pat/src/wabt/src/wast-parser.cc:327: void wabt::(anonymous namespace)::ResolveTypeName(const wabt::Module &, wabt::Type &, wabt::Index, const std::unordered_map<uint32_t, std::string> &): Assertion `type_index != kInvalidIndex' failed.
Aborted (core dumped)

pat@quercus:~/src/crack$ wat2wasm --version
1.0.27

pat@quercus:~/src/crack$ wat2wasm --enable-function-references scratch.wat -o scratch.wasm
wat2wasm: ./src/wast-parser.cc:279: void wabt::{anonymous}::ResolveTypeName(const wabt::Module&, wabt::Type&, wabt::Index, const std::unordered_map<unsigned int, std::__cxx11::basic_string<char> >&): Assertion `type_index != kInvalidIndex' failed.
Aborted (core dumped)

If (ref $T) is replaced with $T, I get an error message. Not a huge problem, just a little confusing.

Start with the reproducing module and the wat2wasm command using --enable-function-references, then inspect ResolveTypeName in src/wast-parser.cc, which appears in the reported assertion. Done means the undefined (ref $T) parameter produces a normal error like the $T case instead of aborting; no test file is named in the report.