diff --git a/base/deprecated.jl b/base/deprecated.jl
index 26ed3243c4ee05..d1a3d05b7820ee 100644
--- a/base/deprecated.jl
+++ b/base/deprecated.jl
@@ -225,6 +225,7 @@ for f in (:sin, :sinh, :sind, :asin, :asinh, :asind,
         :cot, :coth, :cotd, :acot, :acotd,
         :sec, :sech, :secd, :asech,
         :csc, :csch, :cscd, :acsch)
+    @eval import .Math: $f
     @eval @deprecate $f(A::SparseMatrixCSC) $f.(A)
 end
 
@@ -259,6 +260,7 @@ for f in (
         # base/complex.jl
         :cis,
         )
+    @eval import .Math: $f
     @eval @dep_vectorize_1arg Number $f
 end
 # base/fastmath.jl
@@ -267,13 +269,15 @@ for f in ( :acos_fast, :acosh_fast, :angle_fast, :asin_fast, :asinh_fast,
             :cosh_fast, :exp10_fast, :exp2_fast, :exp_fast, :expm1_fast,
             :lgamma_fast, :log10_fast, :log1p_fast, :log2_fast, :log_fast,
             :sin_fast, :sinh_fast, :sqrt_fast, :tan_fast, :tanh_fast )
-    @eval FastMath Base.@dep_vectorize_1arg Number $f
+    @eval import .FastMath: $f
+    @eval @dep_vectorize_1arg Number $f
 end
 for f in (
         :trunc, :floor, :ceil, :round, # base/floatfuncs.jl
         :rad2deg, :deg2rad, :exponent, :significand, # base/math.jl
         :sind, :cosd, :tand, :asind, :acosd, :atand, :asecd, :acscd, :acotd, # base/special/trig.jl
         )
+    @eval import .Math: $f
     @eval @dep_vectorize_1arg Real $f
 end
 # base/complex.jl
@@ -312,11 +316,13 @@ for f in (
         # base/math.jl
         :log, :hypot, :atan2,
     )
+    @eval import .Math: $f
     @eval @dep_vectorize_2arg Number $f
 end
 # base/fastmath.jl
 for f in (:pow_fast, :atan2_fast, :hypot_fast, :max_fast, :min_fast, :minmax_fast)
-    @eval FastMath Base.@dep_vectorize_2arg Number $f
+    @eval import .FastMath: $f
+    @eval @dep_vectorize_2arg Number $f
 end
 for f in (
         :max, :min, # base/math.jl
@@ -737,6 +743,7 @@ end
 for f in (:sec, :sech, :secd, :asec, :asech,
             :csc, :csch, :cscd, :acsc, :acsch,
             :cot, :coth, :cotd, :acot, :acoth)
+    @eval import .Math: $f
     @eval @deprecate $f(A::AbstractArray{<:Number}) $f.(A)
 end
 
@@ -746,6 +753,7 @@ end
 @deprecate complex(A::AbstractArray, B::AbstractArray)  complex.(A, B)
 
 # Deprecate manually vectorized clamp methods in favor of compact broadcast syntax
+import .Math: clamp
 @deprecate clamp(A::AbstractArray, lo, hi) clamp.(A, lo, hi)
 
 # Deprecate manually vectorized round methods in favor of compact broadcast syntax
@@ -845,7 +853,7 @@ end
 @deprecate ~(A::AbstractArray) .~A
 @deprecate ~(B::BitArray) .~B
 
-function frexp(A::Array{<:AbstractFloat})
+function Math.frexp(A::Array{<:AbstractFloat})
     depwarn(string("`frexp(x::Array)` is discontinued. Though not a direct replacement, ",
                    "consider using dot-syntax to `broadcast` scalar `frexp` over `Array`s ",
                    "instead, for example `frexp.(rand(4))`."), :frexp)
@@ -1235,6 +1243,7 @@ end
 for name in ("alnum", "alpha", "cntrl", "digit", "number", "graph",
              "lower", "print", "punct", "space", "upper", "xdigit")
     f = Symbol("is",name)
+    @eval import .UTF8proc: $f
     @eval @deprecate ($f)(s::AbstractString) all($f, s)
 end
 
@@ -1296,9 +1305,11 @@ next(p::Union{Process, ProcessChain}, i::Int) = (getindex(p, i), i + 1)
     return i == 1 ? getfield(p, p.openstream) : p
 end
 
+import .LinAlg: cond
 @deprecate cond(F::LinAlg.LU, p::Integer) cond(full(F), p)
 
 # PR #21359
+import .Random: srand
 @deprecate srand(r::MersenneTwister, filename::AbstractString, n::Integer=4) srand(r, read!(filename, Array{UInt32}(Int(n))))
 @deprecate srand(filename::AbstractString, n::Integer=4) srand(read!(filename, Array{UInt32}(Int(n))))
 @deprecate MersenneTwister(filename::AbstractString)  srand(MersenneTwister(0), read!(filename, Array{UInt32}(Int(4))))
@@ -1308,6 +1319,7 @@ end
 @deprecate versioninfo(io::IO, verbose::Bool) versioninfo(io, verbose=verbose)
 
 # PR #22188
+import .LinAlg: cholfact, cholfact!
 @deprecate cholfact!(A::StridedMatrix, uplo::Symbol, ::Type{Val{false}}) cholfact!(Hermitian(A, uplo), Val(false))
 @deprecate cholfact!(A::StridedMatrix, uplo::Symbol) cholfact!(Hermitian(A, uplo))
 @deprecate cholfact(A::StridedMatrix, uplo::Symbol, ::Type{Val{false}}) cholfact(Hermitian(A, uplo), Val(false))
@@ -1316,6 +1328,7 @@ end
 @deprecate cholfact(A::StridedMatrix, uplo::Symbol, ::Type{Val{true}}; tol = 0.0) cholfact(Hermitian(A, uplo), Val(true), tol = tol)
 
 # PR #22245
+import .LinAlg: isposdef, isposdef!
 @deprecate isposdef(A::AbstractMatrix, UL::Symbol) isposdef(Hermitian(A, UL))
 @deprecate isposdef!(A::StridedMatrix, UL::Symbol) isposdef!(Hermitian(A, UL))
 
@@ -1425,6 +1438,7 @@ export conv, conv2, deconv, filt, filt!, xcorr
 @deprecate cov(X::AbstractVecOrMat, Y::AbstractVecOrMat, vardim::Int, corrected::Bool) cov(X, Y, vardim, corrected=corrected)
 
 # bkfact
+import .LinAlg: bkfact, bkfact!
 function bkfact(A::StridedMatrix, uplo::Symbol, symmetric::Bool = issymmetric(A), rook::Bool = false)
     depwarn("bkfact with uplo and symmetric arguments deprecated. Please use bkfact($(symmetric ? "Symmetric(" : "Hermitian(")A, :$uplo))",
         :bkfact)
@@ -1458,6 +1472,7 @@ end
 @deprecate literal_pow(a, b, ::Type{Val{N}}) where {N} literal_pow(a, b, Val(N)) false
 @eval IteratorsMD @deprecate split(t, V::Type{Val{n}}) where {n} split(t, Val(n)) false
 @deprecate sqrtm(A::UpperTriangular{T},::Type{Val{realmatrix}}) where {T,realmatrix} sqrtm(A, Val(realmatrix))
+import .LinAlg: lufact, lufact!, qrfact, qrfact!, cholfact, cholfact!
 @deprecate lufact(A::AbstractMatrix, ::Type{Val{false}}) lufact(A, Val(false))
 @deprecate lufact(A::AbstractMatrix, ::Type{Val{true}}) lufact(A, Val(true))
 @deprecate lufact!(A::AbstractMatrix, ::Type{Val{false}}) lufact!(A, Val(false))
@@ -1688,6 +1703,7 @@ export hex2num
 @deprecate cfunction(f, r, a::Tuple) cfunction(f, r, Tuple{a...})
 
 # PR 23341
+import .LinAlg: diagm
 @deprecate diagm(A::SparseMatrixCSC) spdiagm(sparsevec(A))
 
 # PR #23373
diff --git a/base/pkg/entry.jl b/base/pkg/entry.jl
index 6dc47473cd17b1..b480645e41f649 100644
--- a/base/pkg/entry.jl
+++ b/base/pkg/entry.jl
@@ -4,8 +4,7 @@ module Entry
 
 import Base: thispatch, nextpatch, nextminor, nextmajor, check_new_version
 import ..Reqs, ..Read, ..Query, ..Resolve, ..Cache, ..Write, ..Dir
-import ...LibGit2
-importall ...LibGit2
+using ...LibGit2
 import ...Pkg.PkgError
 using ..Types
 
diff --git a/base/pkg/write.jl b/base/pkg/write.jl
index ffc2c6f84fb508..bf5078a05c0ea4 100644
--- a/base/pkg/write.jl
+++ b/base/pkg/write.jl
@@ -2,8 +2,8 @@
 
 module Write
 
-import ...LibGit2, ..Cache, ..Read, ...Pkg.PkgError
-importall ...LibGit2
+import ..Cache, ..Read, ...Pkg.PkgError
+using ...LibGit2
 
 function prefetch(pkg::AbstractString, sha1::AbstractString)
     isempty(Cache.prefetch(pkg, Read.url(pkg), sha1)) && return
diff --git a/base/sharedarray.jl b/base/sharedarray.jl
index 479eee1bcc898f..366a0d59eb9fbe 100644
--- a/base/sharedarray.jl
+++ b/base/sharedarray.jl
@@ -1,7 +1,7 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
 import .Serializer: serialize_cycle_header, serialize_type, writetag, UNDEFREF_TAG
-import .Distributed: RRID
+import .Distributed: RRID, procs
 
 mutable struct SharedArray{T,N} <: DenseArray{T,N}
     id::RRID
diff --git a/base/sparse/cholmod.jl b/base/sparse/cholmod.jl
index 062144d3b2be7f..4d5e7188eb5ae0 100644
--- a/base/sparse/cholmod.jl
+++ b/base/sparse/cholmod.jl
@@ -9,14 +9,15 @@ import Base.LinAlg: (\), A_mul_Bc, A_mul_Bt, Ac_ldiv_B, Ac_mul_B, At_ldiv_B, At_
                  cholfact, cholfact!, det, diag, ishermitian, isposdef,
                  issuccess, issymmetric, ldltfact, ldltfact!, logdet
 
-importall ..SparseArrays
+using ..SparseArrays
 
 export
     Dense,
     Factor,
     Sparse
 
-import ..SparseArrays: AbstractSparseMatrix, SparseMatrixCSC, increment, indtype
+import ..SparseArrays: AbstractSparseMatrix, SparseMatrixCSC, increment, indtype, sparse, speye,
+    spzeros, nnz
 
 #########
 # Setup #
diff --git a/base/sparse/umfpack.jl b/base/sparse/umfpack.jl
index 61cc9bf79baa5c..7f7177c55c37c7 100644
--- a/base/sparse/umfpack.jl
+++ b/base/sparse/umfpack.jl
@@ -7,7 +7,7 @@ export UmfpackLU
 import Base: (\), Ac_ldiv_B, At_ldiv_B, findnz, getindex, show, size
 import Base.LinAlg: A_ldiv_B!, Ac_ldiv_B!, At_ldiv_B!, Factorization, det, lufact
 
-importall ..SparseArrays
+using ..SparseArrays
 import ..SparseArrays: increment, increment!, decrement, decrement!, nnz
 
 include("umfpack_h.jl")
diff --git a/base/strings/strings.jl b/base/strings/strings.jl
index bc1f302b7a6ad6..0acad00f79ca76 100644
--- a/base/strings/strings.jl
+++ b/base/strings/strings.jl
@@ -7,4 +7,4 @@ include("strings/search.jl")
 include("strings/util.jl")
 include("strings/io.jl")
 include("strings/utf8proc.jl")
-importall .UTF8proc
+using .UTF8proc
diff --git a/base/sysimg.jl b/base/sysimg.jl
index 676fb70a6ee53a..6c6a3213ba60c5 100644
--- a/base/sysimg.jl
+++ b/base/sysimg.jl
@@ -95,7 +95,7 @@ include("operators.jl")
 include("pointer.jl")
 include("refpointer.jl")
 include("checked.jl")
-importall .Checked
+using .Checked
 
 # buggy handling of ispure in type-inference means this should be
 # after re-defining the basic operations that they might try to call
@@ -132,7 +132,7 @@ Matrix(m::Integer, n::Integer) = Matrix{Any}(Int(m), Int(n))
 # numeric operations
 include("hashing.jl")
 include("rounding.jl")
-importall .Rounding
+using .Rounding
 include("float.jl")
 include("twiceprecision.jl")
 include("complex.jl")
@@ -153,7 +153,7 @@ include("strings/string.jl")
 
 # SIMD loops
 include("simdloop.jl")
-importall .SimdLoop
+using .SimdLoop
 
 # map-reduce operators
 include("reduce.jl")
@@ -219,7 +219,7 @@ using .PermutedDimsArrays
 include("nullable.jl")
 
 include("broadcast.jl")
-importall .Broadcast
+using .Broadcast
 
 # define the real ntuple functions
 @generated function ntuple(f::F, ::Val{N}) where {F,N}
@@ -242,7 +242,7 @@ end
 
 # base64 conversions (need broadcast)
 include("base64.jl")
-importall .Base64
+using .Base64
 
 # version
 include("version.jl")
@@ -267,10 +267,10 @@ include("weakkeydict.jl")
 include("stream.jl")
 include("socket.jl")
 include("filesystem.jl")
-importall .Filesystem
+using .Filesystem
 include("process.jl")
 include("multimedia.jl")
-importall .Multimedia
+using .Multimedia
 include("grisu/grisu.jl")
 import .Grisu.print_shortest
 include("methodshow.jl")
@@ -278,7 +278,8 @@ include("methodshow.jl")
 # core math functions
 include("floatfuncs.jl")
 include("math.jl")
-importall .Math
+using .Math
+import .Math: gamma
 const (√)=sqrt
 const (∛)=cbrt
 
@@ -289,21 +290,21 @@ include("reducedim.jl")  # macros in this file relies on string.jl
 
 # basic data structures
 include("ordering.jl")
-importall .Order
+using .Order
 
 # Combinatorics
 include("sort.jl")
-importall .Sort
+using .Sort
 
 # Fast math
 include("fastmath.jl")
-importall .FastMath
+using .FastMath
 
 function deepcopy_internal end
 
 # BigInts and BigFloats
 include("gmp.jl")
-importall .GMP
+using .GMP
 
 for T in [Signed, Integer, BigInt, Float32, Float64, Real, Complex, Rational]
     @eval flipsign(x::$T, ::Unsigned) = +x
@@ -311,7 +312,7 @@ for T in [Signed, Integer, BigInt, Float32, Float64, Real, Complex, Rational]
 end
 
 include("mpfr.jl")
-importall .MPFR
+using .MPFR
 big(n::Integer) = convert(BigInt,n)
 big(x::AbstractFloat) = convert(BigFloat,x)
 big(q::Rational) = big(numerator(q))//big(denominator(q))
@@ -329,22 +330,24 @@ using .MathConstants: ℯ, π, pi
 # random number generation
 include("random/dSFMT.jl")
 include("random/random.jl")
-importall .Random
+using .Random
+import .Random: rand, rand!
 
 # (s)printf macros
 include("printf.jl")
-importall .Printf
+using .Printf
 
 # metaprogramming
 include("meta.jl")
 
 # enums
 include("Enums.jl")
-importall .Enums
+using .Enums
 
 # concurrency and parallelism
 include("serialize.jl")
-importall .Serializer
+using .Serializer
+import .Serializer: serialize, deserialize
 include("channels.jl")
 
 # memory-mapped and shared arrays
@@ -353,7 +356,7 @@ import .Mmap
 
 # utilities - timing, help, edit
 include("datafmt.jl")
-importall .DataFmt
+using .DataFmt
 include("deepcopy.jl")
 include("interactiveutil.jl")
 include("summarysize.jl")
@@ -372,14 +375,14 @@ include("client.jl")
 
 # Stack frames and traces
 include("stacktraces.jl")
-importall .StackTraces
+using .StackTraces
 
 # misc useful functions & macros
 include("util.jl")
 
 # dense linear algebra
 include("linalg/linalg.jl")
-importall .LinAlg
+using .LinAlg
 const ⋅ = dot
 const × = cross
 
@@ -394,7 +397,7 @@ include("pkg/pkg.jl")
 
 # profiler
 include("profile.jl")
-importall .Profile
+using .Profile
 
 # dates
 include("dates/Dates.jl")
@@ -402,12 +405,12 @@ import .Dates: Date, DateTime, DateFormat, @dateformat_str, now
 
 # sparse matrices, vectors, and sparse linear algebra
 include("sparse/sparse.jl")
-importall .SparseArrays
+using .SparseArrays
 
 include("asyncmap.jl")
 
 include("distributed/Distributed.jl")
-importall .Distributed
+using .Distributed
 include("sharedarray.jl")
 
 # code loading