revert isequal inference improvement (#40594) to fix #42457

JuliaLang · Oct 18, 2021 · 4485586 · 4485586
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commit 4485586
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Showing 2 changed files with 12 additions and 8 deletions.
diff --git a/base/tuple.jl b/base/tuple.jl
@@ -380,14 +380,10 @@ filter(f, t::Tuple) = length(t) < 32 ? filter_rec(f, t) : Tuple(filter(f, collec
 
 ## comparison ##
 
-isequal(t1::Tuple, t2::Tuple) = length(t1) == length(t2) && _isequal(t1, t2)
-_isequal(::Tuple{}, ::Tuple{}) = true
-function _isequal(t1::Tuple{Any,Vararg{Any,N}}, t2::Tuple{Any,Vararg{Any,N}}) where {N}
-    isequal(t1[1], t2[1]) || return false
-    t1, t2 = tail(t1), tail(t2)
-    # avoid dynamic dispatch by telling the compiler relational invariants
-    return isa(t1, Tuple{}) ? true : _isequal(t1, t2::Tuple{Any,Vararg{Any}})
-end
+isequal(t1::Tuple, t2::Tuple) = (length(t1) == length(t2)) && _isequal(t1, t2)
+_isequal(t1::Tuple{}, t2::Tuple{}) = true
+_isequal(t1::Tuple{Any}, t2::Tuple{Any}) = isequal(t1[1], t2[1])
+_isequal(t1::Tuple, t2::Tuple) = isequal(t1[1], t2[1]) && _isequal(tail(t1), tail(t2))
 function _isequal(t1::Any32, t2::Any32)
     for i = 1:length(t1)
         if !isequal(t1[i], t2[i])

diff --git a/test/tuple.jl b/test/tuple.jl
@@ -671,3 +671,11 @@ end
 
 # https://github.com/JuliaLang/julia/issues/40814
 @test Base.return_types(NTuple{3,Int}, (Vector{Int},)) == Any[NTuple{3,Int}]
+
+@testset "inference through isequal #42457" begin
+    function fluffs(a::Tuple{Int,Int,Int}, b::Tuple)::Bool
+        return Base.isequal(a, Base.inferencebarrier(b)::Tuple)
+    end
+
+    @test fluffs((1, 1, 1), (1, 1, 1))
+end