slightly tighten up the getindex case

JuliaLang · Dec 24, 2024 · d1bb027 · d1bb027
1 parent 39fed7d
commit d1bb027
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diff --git a/base/generator_eltype.jl b/base/generator_eltype.jl
@@ -3,9 +3,12 @@ function eltype(::Type{Generator{A, typeof(identity)}}) where {A}
 end
 
 function eltype(::Type{Generator{A, Fix1{typeof(getindex), B}}}) where {A, B}
+    function h(::Type{Type{T}}) where {T}
+        T
+    end
     if B <: Type
         # a user may overload `getindex(user_type)` to return a non-`Vector` `AbstractVector`
-        Any
+        AbstractVector{h(B)}
     elseif (eltype(A) == keytype(B)) || ((eltype(A) <: Integer) && (keytype(B) <: Integer))
         valtype(B)
     else

diff --git a/test/iterators.jl b/test/iterators.jl
@@ -1016,6 +1016,10 @@ end
 end
 
 @testset "`eltype` for `Generator` involving `Fix` and `getindex`/`getfield` (issue #41519)" begin
+    @testset "special cases" begin
+        (f, i) = (Base.Fix1(getindex, Int), [3, 7])
+        @test AbstractVector{Int} >: @inferred eltype(Iterators.map(f, i))
+    end
     @testset "correct `eltype`" begin
         for (f, i) ∈ (
             (Base.Fix1(getindex, Int), [3, 7]),