Precompile statements invalid for value types

[omus]

When using --trace-compile with Julia 1.7.0-DEV.77 (80ace52) I can use the following code:

using Dates
f(::Val{Hour(1)}) = ""
f(Val(Hour(1)))

to generate this precompile statement:

precompile(Tuple{typeof(Main.f), Base.Val{Dates.Hour(value=1)}})

Attempting to use this precompile statement values as Hour doesn't have a keyword constructor:

ERROR: MethodError: no method matching Hour(; value=1)
Closest candidates are:
  (::Type{T})(::Period) where T<:Period at /Users/omus/Development/Julia/latest/usr/share/julia/stdlib/v1.7/Dates/src/periods.jl:404 got unsupported keyword argument "value"
  Hour(::Number) at /Users/omus/Development/Julia/latest/usr/share/julia/stdlib/v1.7/Dates/src/types.jl:34 got unsupported keyword argument "value"
  Hour(::AbstractString) at /Users/omus/Development/Julia/latest/usr/share/julia/stdlib/v1.7/Dates/src/periods.jl:23 got unsupported keyword argument "value"
  ...
Stacktrace:
 [1] top-level scope
   @ REPL[3]:1

Related to: #28808

[NHDaly]

Here's another related case:

let f(x) = x
    precompile(f, (Base.Val{:(=)},))
end

which prints:

precompile(Tuple{Main.var"#f#6", Base.Val{:=}})

which doesn't compile, since Base.Val{:=} is not valid syntax.