getfield codegen for unknown symbol cannot handle tuple inputs

[maleadt]

MWE:

julia> x = (1,)
(1,)

julia> x.x
julia: /home/tim/Julia/src/julia/src/codegen.cpp:3882: bool emit_builtin_call(jl_codectx_t&, jl_cgval_t*, jl_value_t*, const jl_cgval_t*, size_t, jl_value_t*, jl_expr_t*, bool): Assertion `jl_svec_len(fn) == 1' failed.

[3543259] signal (6.-6): Aborted
in expression starting at REPL[2]:1
unknown function (ip: 0x7f865388e83c)
raise at /usr/lib/libc.so.6 (unknown line)
abort at /usr/lib/libc.so.6 (unknown line)
unknown function (ip: 0x7f86538263db)
__assert_fail at /usr/lib/libc.so.6 (unknown line)
emit_builtin_call at /home/tim/Julia/src/julia/src/codegen.cpp:3882
emit_call at /home/tim/Julia/src/julia/src/codegen.cpp:4650
emit_expr at /home/tim/Julia/src/julia/src/codegen.cpp:5572
emit_ssaval_assign at /home/tim/Julia/src/julia/src/codegen.cpp:5162
emit_function at /home/tim/Julia/src/julia/src/codegen.cpp:8517

Looks like the code assumes that the length of jl_field_names equals jl_datatype_nfields, which doesn't hold here: For Tuple{Int}, jl_datatype_nfields (or t->layout->nfields) is 1, while jl_field_names (or t->name->names) returns an empty svec. I guess that's why we specialize Tuple here:

julia/base/reflection.jl

Lines 167 to 172 in 27fa5de

	fieldnames(t::DataType) = (fieldcount(t); # error check to make sure type is specific enough
	(_fieldnames(t)...,))::Tuple{Vararg{Symbol}}
	fieldnames(t::UnionAll) = fieldnames(unwrap_unionall(t))
	fieldnames(::Core.TypeofBottom) =
	throw(ArgumentError("The empty type does not have field names since it does not have instances."))
	fieldnames(t::Type{<:Tuple}) = ntuple(identity, fieldcount(t))