Base: eliminate unused variables (#59727)

Some more unused variables I found while working on #59202 by JETLS.

Author: aviatesk

base/abstractarray.jl

@@ -1684,8 +1684,8 @@ typed_hcat(::Type{T}) where {T} = Vector{T}()
 ## cat: special cases
 vcat(X::T...) where {T}         = T[ X[i] for i=eachindex(X) ]
 vcat(X::T...) where {T<:Number} = T[ X[i] for i=eachindex(X) ]
-hcat(X::T...) where {T}         = T[ X[j] for i=1:1, j=eachindex(X) ]
-hcat(X::T...) where {T<:Number} = T[ X[j] for i=1:1, j=eachindex(X) ]
+hcat(X::T...) where {T}         = T[ X[j] for _=1:1, j=eachindex(X) ]
+hcat(X::T...) where {T<:Number} = T[ X[j] for _=1:1, j=eachindex(X) ]
 
 vcat(X::Number...) = hvcat_fill!(Vector{promote_typeof(X...)}(undef, length(X)), X)
 hcat(X::Number...) = hvcat_fill!(Matrix{promote_typeof(X...)}(undef, 1,length(X)), X)
@@ -1827,7 +1827,7 @@ function cat_shape(dims, shapes::Tuple)
     return out_shape
 end
 # The new way to compute the shape (more inferable than combining cat_size & cat_shape, due to Varargs + issue#36454)
-cat_size_shape(dims) = ntuple(zero, Val(length(dims)))
+cat_size_shape(dims) = ntuple(Returns(0), Val(length(dims)))
 @inline cat_size_shape(dims, X, tail...) = _cat_size_shape(dims, _cshp(1, dims, (), cat_size(X)), tail...)
 _cat_size_shape(dims, shape) = shape
 @inline _cat_size_shape(dims, shape, X, tail...) = _cat_size_shape(dims, _cshp(1, dims, shape, cat_size(X)), tail...)
@@ -1881,7 +1881,7 @@ end
 @inline cat_t(::Type{T}, X...; dims) where {T} = _cat_t(dims, T, X...)
 
 # Why isn't this called `__cat!`?
-__cat(A, shape, catdims, X...) = __cat_offset!(A, shape, catdims, ntuple(zero, length(shape)), X...)
+__cat(A, shape, catdims, X...) = __cat_offset!(A, shape, catdims, ntuple(Returns(0), length(shape)), X...)
 
 function __cat_offset!(A, shape, catdims, offsets, x, X...)
     # splitting the "work" on x from X... may reduce latency (fewer costly specializations)
@@ -2388,13 +2388,13 @@ _typed_hvncat_0d_only_one() =
 function _typed_hvncat(::Type{T}, ::Val{N}) where {T, N}
     N < 0 &&
         throw(ArgumentError("concatenation dimension must be non-negative"))
-    return Array{T, N}(undef, ntuple(x -> 0, Val(N)))
+    return Array{T, N}(undef, ntuple(Returns(0), Val(N)))
 end
 
 function _typed_hvncat(T::Type, ::Val{N}, xs::Number...) where N
     N < 0 &&
         throw(ArgumentError("concatenation dimension must be non-negative"))
-    A = cat_similar(xs[1], T, (ntuple(x -> 1, Val(N - 1))..., length(xs)))
+    A = cat_similar(xs[1], T, (ntuple(Returns(1), Val(N - 1))..., length(xs)))
     hvncat_fill!(A, false, xs)
     return A
 end
@@ -2408,7 +2408,7 @@ function _typed_hvncat(::Type{T}, ::Val{N}, as::AbstractArray...) where {T, N}
         throw(ArgumentError("concatenation dimension must be non-negative"))
     for a ∈ as
         ndims(a) <= N || all(x -> size(a, x) == 1, (N + 1):ndims(a)) ||
-            return _typed_hvncat(T, (ntuple(x -> 1, Val(N - 1))..., length(as), 1), false, as...)
+            return _typed_hvncat(T, (ntuple(Returns(1), Val(N - 1))..., length(as), 1), false, as...)
             # the extra 1 is to avoid an infinite cycle
     end
 
@@ -2423,7 +2423,7 @@ function _typed_hvncat(::Type{T}, ::Val{N}, as::AbstractArray...) where {T, N}
         end
     end
 
-    A = cat_similar(as[1], T, (ntuple(d -> size(as[1], d), N - 1)..., Ndim, ntuple(x -> 1, nd - N)...))
+    A = cat_similar(as[1], T, (ntuple(d -> size(as[1], d), N - 1)..., Ndim, ntuple(Returns(1), nd - N)...))
     k = 1
     for a ∈ as
         for i ∈ eachindex(a)
@@ -2450,7 +2450,7 @@ function _typed_hvncat(::Type{T}, ::Val{N}, as...) where {T, N}
         end
     end
 
-    A = Array{T, nd}(undef, ntuple(x -> 1, Val(N - 1))..., Ndim, ntuple(x -> 1, nd - N)...)
+    A = Array{T, nd}(undef, ntuple(Returns(1), Val(N - 1))..., Ndim, ntuple(Returns(1), nd - N)...)
 
     k = 1
     for a ∈ as
@@ -2518,7 +2518,7 @@ function hvncat_fill!(A::Array, row_first::Bool, xs::Tuple)
             dd = nrc * (d - 1)
             for i ∈ 1:nr
                 Ai = dd + i
-                for j ∈ 1:nc
+                for _ ∈ 1:nc
                     @inbounds A[Ai] = xs[k]
                     k += 1
                     Ai += nr
@@ -2535,7 +2535,7 @@ end
 function _typed_hvncat(T::Type, dims::NTuple{N, Int}, row_first::Bool, as...) where {N}
     # function barrier after calculating the max is necessary for high performance
     nd = max(maximum(cat_ndims(a) for a ∈ as), N)
-    return _typed_hvncat_dims(T, (dims..., ntuple(x -> 1, nd - N)...), row_first, as)
+    return _typed_hvncat_dims(T, (dims..., ntuple(Returns(1), nd - N)...), row_first, as)
 end
 
 function _typed_hvncat_dims(::Type{T}, dims::NTuple{N, Int}, row_first::Bool, as::Tuple) where {T, N}
@@ -2644,7 +2644,7 @@ end
 function _typed_hvncat(T::Type, shape::NTuple{N, Tuple}, row_first::Bool, as...) where {N}
     # function barrier after calculating the max is necessary for high performance
     nd = max(maximum(cat_ndims(a) for a ∈ as), N)
-    return _typed_hvncat_shape(T, (shape..., ntuple(x -> shape[end], nd - N)...), row_first, as)
+    return _typed_hvncat_shape(T, (shape..., ntuple(Returns(shape[end]), nd - N)...), row_first, as)
 end
 
 function _typed_hvncat_shape(::Type{T}, shape::NTuple{N, Tuple}, row_first, as::Tuple) where {T, N}
@@ -2976,8 +2976,8 @@ _vec_axis(A, ax=_iterator_axes(A)) = length(ax) == 1 ? only(ax) : OneTo(prod(len
 end
 
 function _dim_stack!(::Val{dims}, B::AbstractArray, x1, xrest) where {dims}
-    before = ntuple(d -> Colon(), dims - 1)
-    after = ntuple(d -> Colon(), ndims(B) - dims)
+    before = ntuple(Returns(Colon()), dims - 1)
+    after = ntuple(Returns(Colon()), ndims(B) - dims)
 
     i = firstindex(B, dims)
     copyto!(view(B, before..., i, after...), x1)
@@ -3165,8 +3165,7 @@ _sub2ind_vec(i, I1, I...) = (@inline; (I1[i], _sub2ind_vec(i, I...)...))
 _sub2ind_vec(i) = ()
 
 function _ind2sub(inds::Union{DimsInteger{N},Indices{N}}, ind::AbstractVector{<:Integer}) where N
-    M = length(ind)
-    t = ntuple(n->similar(ind),Val(N))
+    t = ntuple(_->similar(ind),Val(N))
     for (i,idx) in pairs(IndexLinear(), ind)
         sub = _ind2sub(inds, idx)
         for j = 1:N

base/array.jl

@@ -1141,7 +1141,6 @@ function _growbeg!(a::Vector, delta::Integer)
     delta == 0 && return # avoid attempting to index off the end
     delta >= 0 || throw(ArgumentError("grow requires delta >= 0"))
     ref = a.ref
-    mem = ref.mem
     len = length(a)
     offset = memoryrefoffset(ref)
     newlen = len + delta
@@ -1420,7 +1419,6 @@ append!(a::AbstractVector, iter...) = (foreach(v -> append!(a, v), iter); a)
 
 function _append!(a::AbstractVector, ::Union{HasLength,HasShape}, iter)
     n = Int(length(iter))::Int
-    i = lastindex(a)
     sizehint!(a, length(a) + n; shrink=false)
     for item in iter
         push!(a, item)
@@ -1764,7 +1762,6 @@ function pushfirst!(a::Vector{Any}, @nospecialize x)
 end
 function pushfirst!(a::Vector{Any}, @nospecialize x...)
     @_terminates_locally_meta
-    na = length(a)
     nx = length(x)
     _growbeg!(a, nx)
     @_safeindex for i = 1:nx
@@ -1878,7 +1875,6 @@ function deleteat!(a::Vector, r::AbstractUnitRange{<:Integer})
     if eltype(r) === Bool
         return invoke(deleteat!, Tuple{Vector, AbstractVector{Bool}}, a, r)
     else
-        n = length(a)
         f = first(r)
         f isa Bool && depwarn("passing Bool as an index is deprecated", :deleteat!)
         isempty(r) || _deleteat!(a, f, length(r))

base/dict.jl

@@ -166,7 +166,7 @@ end
         @inbounds if (olds[i] & 0x80) != 0
             k = oldk[i]
             v = oldv[i]
-            index, sh = hashindex(k, newsz)
+            index, _ = hashindex(k, newsz)
             index0 = index
             while slots[index] != 0
                 index = (index & (newsz-1)) + 1

base/essentials.jl

@@ -385,10 +385,10 @@ function checkbounds(A::Union{Array, GenericMemory}, i::Int)
     checkbounds(Bool, A, i) || throw_boundserror(A, (i,))
 end
 
-default_access_order(a::GenericMemory{:not_atomic}) = :not_atomic
-default_access_order(a::GenericMemory{:atomic}) = :monotonic
-default_access_order(a::GenericMemoryRef{:not_atomic}) = :not_atomic
-default_access_order(a::GenericMemoryRef{:atomic}) = :monotonic
+default_access_order(::GenericMemory{:not_atomic}) = :not_atomic
+default_access_order(::GenericMemory{:atomic}) = :monotonic
+default_access_order(::GenericMemoryRef{:not_atomic}) = :not_atomic
+default_access_order(::GenericMemoryRef{:atomic}) = :monotonic
 
 function getindex(A::GenericMemory, i::Int)
     @_noub_if_noinbounds_meta
@@ -464,7 +464,7 @@ See also: [`round`](@ref), [`trunc`](@ref), [`oftype`](@ref), [`reinterpret`](@r
 function convert end
 
 # ensure this is never ambiguous, and therefore fast for lookup
-convert(T::Type{Union{}}, x...) = throw(ArgumentError("cannot convert a value to Union{} for assignment"))
+convert(::Type{Union{}}, _...) = throw(ArgumentError("cannot convert a value to Union{} for assignment"))
 
 convert(::Type{Type}, x::Type) = x # the ssair optimizer is strongly dependent on this method existing to avoid over-specialization
                                    # in the absence of inlining-enabled
@@ -513,7 +513,7 @@ Modifying the key-space of the underlying data may invalidate this object.
 """
 Pairs
 
-argtail(x, rest...) = rest
+argtail(_, rest...) = rest
 
 """
     tail(x::Tuple)::Tuple
@@ -576,7 +576,7 @@ end
 
 # remove concrete constraint on diagonal TypeVar if it comes from troot
 function widen_diagonal(@nospecialize(t), troot::UnionAll)
-    body = ccall(:jl_widen_diagonal, Any, (Any, Any), t, troot)
+    return ccall(:jl_widen_diagonal, Any, (Any, Any), t, troot)
 end
 
 function isvarargtype(@nospecialize(t))
@@ -981,7 +981,7 @@ getindex(v::SimpleVector, i::Int) = (@_foldable_meta; Core._svec_ref(v, i))
 function length(v::SimpleVector)
     Core._svec_len(v)
 end
-firstindex(v::SimpleVector) = 1
+firstindex(::SimpleVector) = 1
 lastindex(v::SimpleVector) = length(v)
 iterate(v::SimpleVector, i=1) = (length(v) < i ? nothing : (v[i], i + 1))
 eltype(::Type{SimpleVector}) = Any
@@ -1229,7 +1229,7 @@ to obtain a definitive answer.
 
 See also [`iterate`](@ref), [`isempty`](@ref)
 """
-isdone(itr, state...) = missing
+isdone(_, _...) = missing
 
 """
     iterate(iter [, state])::Union{Nothing, Tuple{Any, Any}}

base/operators.jl

@@ -288,9 +288,9 @@ orderings such as [`isless`](@ref).
 !!! compat "Julia 1.7"
     This function requires Julia 1.7 or later.
 """
-isunordered(x) = false
+isunordered(_) = false
 isunordered(x::AbstractFloat) = isnan(x)
-isunordered(x::Missing) = true
+isunordered(::Missing) = true
 
 ==(T::Type, S::Type) = (@_total_meta; ccall(:jl_types_equal, Cint, (Any, Any), T, S) != 0)
 ==(T::TypeVar, S::Type) = false