improve some inferrabilities (#41495)

base/errorshow.jl

@@ -222,7 +222,7 @@ function showerror(io::IO, ex::MethodError)
  arg_types = (is_arg_types ? ex.args : typesof(ex.args...))::DataType
  f = ex.f
  meth = methods_including_ambiguous(f, arg_types)
- if length(meth) > 1
+ if isa(meth, MethodList) && length(meth) > 1
  return showerror_ambiguous(io, meth, f, arg_types)
  end
  arg_types_param::SimpleVector = arg_types.parameters
@@ -898,4 +898,3 @@ function show(io::IO, ::MIME"text/plain", stack::ExceptionStack)
  show_exception_stack(io, stack)
 end
 show(io::IO, stack::ExceptionStack) = show(io, MIME("text/plain"), stack)
-

base/process.jl

@@ -84,15 +84,16 @@ const SpawnIOs = Vector{Any} # convenience name for readability
  for io in stdio]
  handle = Libc.malloc(_sizeof_uv_process)
  disassociate_julia_struct(handle) # ensure that data field is set to C_NULL
+ (; exec, flags, env, dir) = cmd
  err = ccall(:jl_spawn, Int32,
  (Cstring, Ptr{Cstring}, Ptr{Cvoid}, Ptr{Cvoid},
  Ptr{Tuple{Cint, UInt}}, Int,
  UInt32, Ptr{Cstring}, Cstring, Ptr{Cvoid}),
- file, cmd.exec, loop, handle,
+ file, exec, loop, handle,
  iohandles, length(iohandles),
- cmd.flags,
- cmd.env === nothing ? C_NULL : cmd.env,
- isempty(cmd.dir) ? C_NULL : cmd.dir,
+ flags,
+ env === nothing ? C_NULL : env,
+ isempty(dir) ? C_NULL : dir,
  @cfunction(uv_return_spawn, Cvoid, (Ptr{Cvoid}, Int64, Int32)))
  if err != 0
  ccall(:jl_forceclose_uv, Cvoid, (Ptr{Cvoid},), handle) # will call free on handle eventually

base/toml_parser.jl

@@ -323,7 +323,7 @@ function Base.showerror(io::IO, err::ParserError)
  # In this case we want the arrow to point one character
  pos = err.pos::Int
  err.type == ErrUnexpectedEofExpectedValue && (pos += 1)
- str1, err1 = point_to_line(err.str, pos, pos, io)
+ str1, err1 = point_to_line(err.str::String, pos, pos, io)
  @static if VERSION <= v"1.6.0-DEV.121"
  # See https://github.com/JuliaLang/julia/issues/36015
  format_fixer = get(io, :color, false) == true ? "\e[0m" : ""