fix invalidations for Dicts from Static.jl

[ranocha]

This should hopefully fix quite some invalidations coming from Static.jl.

Here is the code:

               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.8.0 (2022-08-17)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |

(@v1.8) pkg> activate --temp

(jl_PDrBpd) pkg> add Static
    Updating registry at `~/.julia/registries/General.toml`
   Resolving package versions...
    Updating `/tmp/jl_PDrBpd/Project.toml`
  [aedffcd0] + Static v0.7.6
    Updating `/tmp/jl_PDrBpd/Manifest.toml`
  [615f187c] + IfElse v0.1.1
  [aedffcd0] + Static v0.7.6

julia> using SnoopCompileCore

julia> invalidations = @snoopr using Static

julia> using SnoopCompile

julia> trees = invalidation_trees(invalidations)
7-element Vector{SnoopCompile.MethodInvalidations}:
...
 inserting !(::False) in Static at ~/.julia/packages/Static/sVI3g/src/Static.jl:427 invalidated:
...
                 161: signature Tuple{typeof(!), Any} triggered MethodInstance for setindex!(::Dict{_A, Nothing} where _A, ::Nothing, ::Any) (193 children)
                 162: signature Tuple{typeof(!), Any} triggered MethodInstance for setindex!(::Dict, ::Any, ::Any) (424 children)

Since !isequal(...) is used here in an if stament - and if statements only accept Bools -
it appears to be sane to assert that isequal returns a Bool here.

See also #46481

[oscardssmith]

Rather than going 1 by 1 and type annotating every if, it seems to me like we might be able to teach type inference that anything that goes into an if statement must be a boolean. @JeffBezanson does that seem possible to you?

[ranocha]

That would be nice, of course. However, that would basically mean annotating

if (!isequal(key, key0))::Bool

automatically but we need

if !(isequal(key, key0)::Bool)

in this case to fix the invalidations (stemming from a new definition of !).

[ChrisRackauckas]

Also, I'd be very weary of "perfect is the enemy of good" here. We can come up with some super elegant solution that fixes all problems and is released in Julia v1.11, but really though, this is a nice small fix that will improve a lot of things so even if there's some big grand plans I'd want this kind of thing in 1.8.1 ASAP as it has major real-world user effects.

[gbaraldi]

Don't we already assume that anything that goes to an if is a bool, and if it isn't we error? Or is that just a runtime check not a compile time one?

[ranocha]

Don't we already assume that anything that goes to an if is a bool, and if it isn't we error? Or is that just a runtime check not a compile time one?

I do not know. Even if we do, that's not the problem this PR is intended to fix - the input of ! in the if block is the problem, not the output of !.

[timholy]

Test failure https://buildkite.com/julialang/julia-master/builds/15063#0182d9a2-cb0e-4c97-95ec-f16ab36b312c looks like memory corruption; I ran

julia> badm = Ref{Any}()
Base.RefValue{Any}(#undef)

julia> for _ in 1:10^6
           A  = 10*I + sprandn(10, 10, 0.4)
           badm[] = copy(A)
           F1 = lu(A)
           any(isnan, F1.nzval) && error("NaN")
       end

and never got an instance of NaN.

[ranocha]

Thanks a lot! Can we get a backport-1.8 label for this to get it into Julia v1.8.1?

[ranocha]

Thanks!

[vtjnash]

Rather than going 1 by 1 and type annotating every if, it seems to me like we might be able to teach type inference that anything that goes into an if statement must be a boolean. @JeffBezanson does that seem possible to you?

It is doable by moving the ! to the end, but doesn't read quite as cleanly:

julia> if false else # if !false
           1
       end

though has the advantage that parenthesis are never needed for it.