# This file is a part of Julia. License is MIT: https://julialang.org/license

# Internal changes mechanism.
# Instructions for Julia Core Developers:
# 1. When making a breaking change that is known to be depended upon by an
#    important and closely coupled package, decide on a unique `change_name`
#    for your PR and add it to the list below. In general, it is better to
#    err on the side of caution and assign a `change_name` even if it is not
#    clear that it is required. `change_name`s may also be assigned after the
#    fact in a separate PR. (Note that this may cause packages to misbehave
#    on versions in between the change and the assignment of the `change_name`,
#    but this is often still better than the alternative of misbehaving on unknown
#    versions).

# Instructions for Release Managers:
# 1. Upon tagging any release, clear the list of internal changes.
# 2. Upon tagging an -alpha version
#    a. On master, set __next_removal_version to v"1.(x+1)-alpha"
#    b. On the release branch, set __next_removal_version to v"1.x" (no -alpha)
# 3. Upon tagging a release candidate, clear the list of internal changes and
#    set __next_removal_version to `nothing`.
const __next_removal_version = v"1.12-alpha"
const __internal_changes_list = (
    :invertedlinetables,
    :codeinforefactor,
    :miuninferredrm,
    :codeinfonargs, #54341
    :ocnopartial,
    :printcodeinfocalls,
    :syntacticccall, #59165
    :svectvar, #61645
    :syntacticcglobal, #61709
    # Add new change names above this line
)

if !isempty(__internal_changes_list)
    if VERSION == __next_removal_version
        error("You have tagged a new release without clearing the internal changes list.")
    end
elseif __next_removal_version === nothing
    error("You have tagged a new release candidate without clearing the internal changes list.")
end

"""
    __has_internal_change(version_or::VersionNumber, change_name::Symbol)

Some Julia packages have known dependencies on Julia internals (e.g. for introspection of
internal julia datastructures). To ease the co-development of such packages with julia,
a `change_name` is assigned on a best-effort basis or when explicitly requested.
This `change_name` can be used to probe whether or not the particular pre-release build of julia has
a particular change. In particular this function tests change scheduled for `version_or`
is present in our current julia build, either because our current version
is greater than `version_or` or because we're running a pre-release build that
includes the change.

Using this mechanism is a superior alternative to commit-number based `VERSION`
comparisons, which can be brittle during pre-release stages when there are multiple
actively developed branches.

The list of changes is cleared twice during the release process:
1. With the release of the first alpha
2. For the first release candidate

No new `change_name`s will be added during release candidates or bugfix releases
(so in particular on any released version, the list of changes will be empty and
`__has_internal_change` will always be equivalent to a version comparison.

# Example

Julia version `v"1.12.0-DEV.173"` changed the internal representation of line number debug info.
Several debugging packages have custom code to display this information and need to be changed
accordingly. In previous practice, this would often be accomplished with something like the following
```
@static if VERSION > v"1.12.0-DEV.173"
    # Code to handle new format
else
    # Code to handle old format
end
```

However, because such checks cannot be introduced until a VERSION number is assigned
(which also automatically pushes out the change to all nightly users), there was a builtin period
of breakage. With `__has_internal_change`, this can instead be written as:

```
@static if __has_internal_change(v"1.12-alpha", :invertedlinenames)
    # Code to handle new format
else
    # Code to handle old format
end
```

To find out the correct version to use as the first argument, you may use
`Base.__next_removal_version`, which is set to the next version number in which
the list of changes will be cleared.

The primary advantage of this approach is that it allows a new version of the
package to be tagged and released *in advance* of the break on the nightly
build, thus ensuring continuity of package operation for nightly users.

!!! warning

    This functionality is intended to help package developers which make use of
    internal julia functionality. Doing so is explicitly discouraged unless absolutely
    required and comes with the explicit understanding that the package will break.
    In particular, this is not a generic feature-testing mechanism, but only a
    simple, courtesy coordination mechanism for changes that are known (or found) to
    be breaking a package depending on julia internals.
"""
function __has_internal_change(version_or::VersionNumber, change_name::Symbol)
    VERSION > version_or && return true
    change_name in __internal_changes_list
end
export __has_internal_change

# Deprecated functions and objects
#
# Please add new deprecations at the bottom of the file.
# A function deprecated in a release will be removed in the next one.
# Please also add a reference to the pull request which introduced the
# deprecation. For simple cases where a direct replacement is available,
# use @deprecate. @deprecate takes care of calling the replacement
# and of exporting the function.
#
# For more complex cases, move the body of the deprecated method in this file,
# and call depwarn() directly from inside it.

"""
    @deprecate old new [export_old=true]

Deprecate method `old` and specify the replacement call `new`, defining a new method `old`
with the specified signature in the process.

To prevent `old` from being exported, set `export_old` to `false`.

See also [`Base.depwarn()`](@ref).

!!! compat "Julia 1.5"
    As of Julia 1.5, functions defined by `@deprecate` do not print warning when `julia`
    is run without the `--depwarn=yes` flag set, as the default value of `--depwarn` option
    is `no`.  The warnings are printed from tests run by `Pkg.test()`.

# Examples
```jldoctest
julia> @deprecate old_export(x) new(x)
old_export (generic function with 1 method)

julia> @deprecate old_public(x) new(x) false
old_public (generic function with 1 method)
```

Calls to `@deprecate` without explicit type-annotations will define
deprecated methods accepting any number of positional and keyword
arguments of type `Any`.

!!! compat "Julia 1.9"
    Keyword arguments are forwarded when there is no explicit type
    annotation as of Julia 1.9. For older versions, you can manually
    forward positional and keyword arguments by doing `@deprecate
    old(args...; kwargs...) new(args...; kwargs...)`.

To restrict deprecation to a specific signature, annotate the
arguments of `old`. For example,
```jldoctest; filter = r"@ .*"a
julia> new(x::Int) = x;

julia> new(x::Float64) = 2x;

julia> @deprecate old(x::Int) new(x);

julia> methods(old)
# 1 method for generic function "old" from Main:
 [1] old(x::Int64)
     @ deprecated.jl:94
```
will define and deprecate a method `old(x::Int)` that mirrors `new(x::Int)` but will not
define nor deprecate the method `old(x::Float64)`.
"""
macro deprecate(old, new, export_old=true)
    function cannot_export_nonsymbol()
        error(
            "if the third `export_old` argument is not specified or `true`, the first",
            " argument must be of form",
            " (1) `f(...)` where `f` is a symbol,",
            " (2) `T{...}(...)` where `T` is a symbol, or",
            " (3) a symbol.",
        )
    end
    meta = Expr(:meta, :noinline)
    if isa(old, Expr) && (old.head === :call || old.head === :where)
        remove_linenums!(new)
        oldcall = sprint(show_unquoted, old)
        newcall = sprint(show_unquoted, new)
        # if old.head is a :where, step down one level to the :call to avoid code duplication below
        callexpr = old.head === :call ? old : old.args[1]
        maybe_export = nothing
        if callexpr.head === :call
            fnexpr = callexpr.args[1]
            if fnexpr isa Expr && fnexpr.head === :curly
                fnexpr = fnexpr.args[1]
            end
            if export_old
                if fnexpr isa Symbol
                    maybe_export = Expr(:export, esc(fnexpr))
                else
                    cannot_export_nonsymbol()
                end
            end
        else
            error("invalid usage of @deprecate")
        end
        ex = :($(esc(old)) = begin
            $meta
            depwarn($"`$oldcall` is deprecated, use `$newcall` instead.", Core.Typeof($(esc(fnexpr))).name.singletonname)
            $(esc(new))
        end)
        Expr(:toplevel, maybe_export, replace_linenums!(ex, __source__))
    else
        if export_old && !(old isa Symbol)
            cannot_export_nonsymbol()
        end
        ex = :(function $(esc(old))(args...; kwargs...)
            $meta
            depwarn($"`$old` is deprecated, use `$new` instead.", Core.Typeof($(esc(old))).name.singletonname)
            $(esc(new))(args...; kwargs...)
        end)
        Expr(:toplevel,
            export_old ? Expr(:export, esc(old)) : nothing,
            replace_linenums!(ex, __source__))
    end
end

"""
    Base.depwarn(msg::String, funcsym::Symbol; force=false)

Print `msg` as a deprecation warning. The symbol `funcsym` should be the name
of the calling function, which is used to ensure that the deprecation warning is
only printed the first time for each call place. Set `force=true` to force the
warning to always be shown, even if Julia was started with `--depwarn=no` (the
default).

See also [`@deprecate`](@ref).

# Examples
```julia
function deprecated_func()
    Base.depwarn("Don't use `deprecated_func()`!", :deprecated_func)

    1 + 1
end
```
"""
@nospecializeinfer function depwarn(msg, funcsym; force::Bool=false)
    @nospecialize
    # N.B. With this use of `@invokelatest`, we're preventing the addition of backedges from
    # callees, such as `convert`, to this user-facing method. This approach is designed to
    # enhance the resilience of packages that utilize `depwarn` against invalidation.
    return @invokelatest _depwarn(msg, funcsym, force)
end
@nospecializeinfer function _depwarn(msg, funcsym, force::Bool)
    @nospecialize
    opts = JLOptions()
    if opts.depwarn == 2
        throw(ErrorException(msg))
    end
    deplevel = force || opts.depwarn == 1 ? CoreLogging.Warn : CoreLogging.BelowMinLevel
    @logmsg(
        deplevel,
        msg,
        _module=begin
            bt = backtrace()
            frame, caller = firstcaller(bt, funcsym)
            linfo = caller.linfo
            if linfo isa Core.MethodInstance
                def = linfo.def
                def isa Module ? def : def.module
            else
                Core    # TODO: Is it reasonable to attribute callers without linfo to Core?
            end
        end,
        _file=String(caller.file),
        _line=caller.line,
        _id=(frame,funcsym),
        _group=:depwarn,
        caller=caller,
        maxlog=funcsym === nothing ? nothing : 1
    )
    nothing
end

firstcaller(bt::Vector, ::Nothing) = Ptr{Cvoid}(0), StackTraces.UNKNOWN
firstcaller(bt::Vector, funcsym::Symbol) = firstcaller(bt, (funcsym,))
function firstcaller(bt::Vector, funcsyms)
    # Identify the calling line
    found = false
    for ip in bt
        lkups = StackTraces.lookup(ip)
        for lkup in lkups
            if lkup == StackTraces.UNKNOWN || lkup.from_c
                continue
            end
            if found
                return ip, lkup
            end
            found = lkup.func in funcsyms
            # look for constructor type name
            if !found
                li = lkup.linfo
                if li isa Core.MethodInstance
                    def = li.def
                    found = def isa Method && def.name in funcsyms
                end
            end
        end
    end
    return C_NULL, StackTraces.UNKNOWN
end

deprecate(m::Module, s::Symbol, flag=1) = ccall(:jl_deprecate_binding, Cvoid, (Any, Any, Cint), m, s, flag)

macro deprecate_binding(old, new, export_old=true, dep_message=:nothing, constant=true)
    dep_message === :nothing && (dep_message = ", use $new instead.")
    return Expr(:toplevel,
         export_old ? Expr(:export, esc(old)) : nothing,
         Expr(:const, Expr(:(=), esc(Symbol(string("_dep_message_",old))), esc(dep_message))),
         constant ? Expr(:const, Expr(:(=), esc(old), esc(new))) : Expr(:(=), esc(old), esc(new)),
         Expr(:call, :deprecate, __module__, Expr(:quote, old)))
end

macro deprecate_stdlib(old, mod, export_old=true, newname=old)
    rename = old === newname ? "" : " as `$newname`"
    dep_message = """: it has been moved to the standard library package `$mod`$rename.
                        Add `using $mod` to your imports."""
    new = GlobalRef(Base.root_module(Base, mod), newname)
    return Expr(:toplevel,
         export_old ? Expr(:export, esc(old)) : nothing,
         Expr(:const, Expr(:(=), esc(Symbol(string("_dep_message_",old))), esc(dep_message))),
         Expr(:const, Expr(:(=), esc(old), esc(new))),
         Expr(:call, :deprecate, __module__, Expr(:quote, old)))
end

macro deprecate_moved(old, new, export_old=true)
    eold = esc(old)
    emsg = string(old, " has been moved to the package ", new, ".jl.\n",
        "Run `Pkg.add(\"", new, "\")` to install it, restart Julia,\n",
        "and then run `using ", new, "` to load it.")
    return Expr(:toplevel,
        replace_linenums!(:($eold(args...; kwargs...) = error($emsg)), __source__),
        export_old ? Expr(:export, eold) : nothing,
        Expr(:call, :deprecate, __module__, Expr(:quote, old), 2))
end

# BEGIN 1.0 deprecations

@deprecate one(i::CartesianIndex)                    oneunit(i)
@deprecate one(I::Type{CartesianIndex{N}}) where {N} oneunit(I)

import .MPFR: BigFloat
@deprecate BigFloat(x, prec::Int)                               BigFloat(x; precision=prec)
@deprecate BigFloat(x, prec::Int, rounding::RoundingMode)       BigFloat(x, rounding; precision=prec)
@deprecate BigFloat(x::Real, prec::Int)                         BigFloat(x; precision=prec)
@deprecate BigFloat(x::Real, prec::Int, rounding::RoundingMode) BigFloat(x, rounding; precision=prec)

# END 1.0 deprecations

# BEGIN 1.5 deprecations

"""
    isimmutable(v) -> Bool
!!! warning
    Consider using `!ismutable(v)` instead, as `isimmutable(v)` will be replaced by `!ismutable(v)` in a future release. (Since Julia 1.5)
Return `true` iff value `v` is immutable.  See [Mutable Composite Types](@ref)
for a discussion of immutability. Note that this function works on values, so if you give it
a type, it will tell you that a value of `DataType` is mutable.

# Examples
```jldoctest
julia> isimmutable(1)
true

julia> isimmutable([1,2])
false
```
"""
isimmutable(@nospecialize(x)) = !ismutable(x)
export isimmutable
# Note isimmutable is not @deprecated out of performance concerns

macro get!(h, key0, default)
    f, l = __source__.file, __source__.line
    @warn "`@get!(dict, key, default)` at $f:$l is deprecated, use `get!(()->default, dict, key)` instead."
    return quote
        get!(()->$(esc(default)), $(esc(h)), $(esc(key0)))
    end
end

pointer(V::SubArray{<:Any,<:Any,<:Array,<:Tuple{Vararg{RangeIndex}}}, is::Tuple) = pointer(V, CartesianIndex(is))

# END 1.5 deprecations

# BEGIN 1.6 deprecations

# These changed from SimpleVector to `MethodMatch`. These definitions emulate
# being a SimpleVector to ease transition for packages that make explicit
# use of (internal) APIs that return raw method matches.
iterate(match::Core.MethodMatch, field::Int=1) =
    field > nfields(match) ? nothing : (getfield(match, field), field+1)
getindex(match::Core.MethodMatch, field::Int) =
    getfield(match, field)


# these were internal functions, but some packages seem to be relying on them
tuple_type_head(T::Type) = fieldtype(T, 1)
tuple_type_cons(::Type, ::Type{Union{}}) = Union{}
@assume_effects :foldable tuple_type_cons(::Type{S}, ::Type{T}) where T<:Tuple where S =
    Tuple{S, T.parameters...}
@assume_effects :foldable parameter_upper_bound(t::UnionAll, idx) =
    rewrap_unionall((unwrap_unionall(t)::DataType).parameters[idx], t)

# these were internal functions, but some packages seem to be relying on them
@deprecate cat_shape(dims, shape::Tuple{}, shapes::Tuple...) cat_shape(dims, shapes) false
cat_shape(dims, shape::Tuple{}) = () # make sure `cat_shape(dims, ())` do not recursively calls itself

@deprecate unsafe_indices(A) axes(A) false
@deprecate unsafe_length(r) length(r) false

# these were internal type aliases, but some packages seem to be relying on them
const Any16{N} = Tuple{Any,Any,Any,Any,Any,Any,Any,Any,
                        Any,Any,Any,Any,Any,Any,Any,Any,Vararg{Any,N}}
const All16{T,N} = Tuple{T,T,T,T,T,T,T,T,
                         T,T,T,T,T,T,T,T,Vararg{T,N}}

# END 1.6 deprecations

# BEGIN 1.7 deprecations

# the plan is to eventually overload getproperty to access entries of the dict
@noinline function getproperty(x::Pairs, s::Symbol)
    s == :data && depwarn("use values(kwargs) instead of kwargs.data", :getproperty, force=true)
    s == :itr && depwarn("use keys(kwargs) instead of kwargs.itr", :getproperty, force=true)
    return getfield(x, s)
end

# This function was marked as experimental and not exported.
@deprecate catch_stack(task=current_task(); include_bt=true) current_exceptions(task; backtrace=include_bt) false

# END 1.7 deprecations

# BEGIN 1.8 deprecations

const var"@_inline_meta" = var"@inline"
const var"@_noinline_meta" = var"@noinline"
@deprecate getindex(t::Tuple, i::Real) t[convert(Int, i)]

# END 1.8 deprecations

# BEGIN 1.9 deprecations

# We'd generally like to avoid direct external access to internal fields
# Core.Compiler.is_inlineable and Core.Compiler.set_inlineable! move towards this direction,
# but we need to keep these around for compat
function getproperty(ci::CodeInfo, s::Symbol)
    s === :inlineable && return Core.Compiler.is_inlineable(ci)
    return getfield(ci, s)
end

function setproperty!(ci::CodeInfo, s::Symbol, v)
    s === :inlineable && return Core.Compiler.set_inlineable!(ci, v)
    return setfield!(ci, s, convert(fieldtype(CodeInfo, s), v))
end

@eval Threads nthreads() = threadpoolsize()

@eval Threads begin
    """
        resize_nthreads!(A, copyvalue=A[1])

    Resize the array `A` to length [`nthreads()`](@ref).   Any new
    elements that are allocated are initialized to `deepcopy(copyvalue)`,
    where `copyvalue` defaults to `A[1]`.

    This is typically used to allocate per-thread variables, and
    should be called in `__init__` if `A` is a global constant.

    !!! warning

        This function is deprecated, since as of Julia v1.9 the number of
        threads can change at run time. Instead, per-thread state should be
        created as needed based on the thread id of the caller.
    """
    function resize_nthreads!(A::AbstractVector, copyvalue=A[1])
        nthr = nthreads()
        nold = length(A)
        resize!(A, nthr)
        for i = nold+1:nthr
            A[i] = deepcopy(copyvalue)
        end
        return A
    end
end

# END 1.9 deprecations

# BEGIN 1.10 deprecations

"""
    @pure ex

`@pure` gives the compiler a hint for the definition of a pure function,
helping for type inference.

!!! warning
    This macro is intended for internal compiler use and may be subject to changes.

!!! warning
    In Julia 1.8 and higher, it is favorable to use [`@assume_effects`](@ref) instead of `@pure`.
    This is because `@assume_effects` allows a finer grained control over Julia's purity
    modeling and the effect system enables a wider range of optimizations.
"""
macro pure(ex)
    return esc(:(Base.@assume_effects :foldable $ex))
end

# END 1.10 deprecations

# BEGIN 1.11 deprecations

# these were never a part of the public API and so they can be removed without deprecation
# in a minor release but we're being nice and trying to avoid transient breakage.
@deprecate permute!!(a, p::AbstractVector{<:Integer}) permute!(a, p) false
@deprecate invpermute!!(a, p::AbstractVector{<:Integer}) invpermute!(a, p) false

# END 1.11 deprecations

# BEGIN 1.12 deprecations

@deprecate isbindingresolved(m::Module, var::Symbol) true false

"""
    isbindingresolved(m::Module, s::Symbol) -> Bool

Return whether the binding of a symbol in a module is resolved.

See also [`isexported`](@ref), [`ispublic`](@ref), [`isdeprecated`](@ref).

```jldoctest
julia> module Mod
           foo() = 17
       end
Mod

julia> Base.isbindingresolved(Mod, :foo)
true
```

!!! warning
    This function is deprecated. The concept of binding "resolvedness" was removed in Julia 1.12.
    The function now always returns `true`.
"""
isbindingresolved

# Some packages call this function
function to_power_type(x::Number)
    T = promote_type(typeof(x), typeof(x*x))
    convert(T, x)
end
to_power_type(x) = oftype(x*x, x)

# END 1.12 deprecations

# BEGIN 1.13 deprecations

@deprecate merge(combine::Callable, d::AbstractDict, others::AbstractDict...) mergewith(combine, d, others...)

# end 1.13 deprecations

# BEGIN 1.14 deprecations

# These operators are new in 1.14, but these fallback methods are added for
# compatibility while packages adjust to defining both operators, to allow
# Base and other packages to start using these.
*%(a::T, b::T) where {T} = *(a, b)
+%(a::T, b::T) where {T} = +(a, b)
-%(a::T, b::T) where {T} = -(a, b)

# Revise calls this
function explicit_manifest_entry_path(args...)
    spec = explicit_manifest_entry_load_spec(args...)
    spec === nothing && return nothing
    return spec.path
end

# These functions get called from generated functions a lot where printing causes errors. We have the following options:
# 1. Use ordinary depwarn. This breaks generated functions that use these deprecations, defeating the point.
# 2. Always error in generated functions. This would probably be best (the depwarn would run at expansion time),
#    but it completely breaks inference of these generated functions and some of them are important.
# 3. Never print a warning in generated functions (but do throw the error if --depwarn=error).
#
# We choose option 3. It's not ideal, because users that never use --depwarn=error will never see the warning,
# but it's the least bad tradeoff among the lot.
function depwarn_if_not_pure(args...)
    opts = JLOptions()
    opts.depwarn != 2 && ccall(:jl_is_in_pure_context, Bool, ()) && return
    depwarn(args...)
end

@noinline function getproperty(x::TypeEq, s::Symbol)
    if s === :parameters
        depwarn_if_not_pure("accessing `Type.parameters` is deprecated; use `Base.type_parameter(x)` instead", :getproperty)
        return Core.svec(type_parameter(x))
    elseif s === :name
        depwarn_if_not_pure("accessing `Type.name` is deprecated without replacement. If for detection, use `Base.isType(x)`.", :getproperty)
        return TypeEq.name
    elseif s === :hash
        depwarn_if_not_pure("accessing `Type.hash` is deprecated; use `Base._jl_type_cache_hash(x)` instead", :getproperty)
        return reinterpret(Int32, UInt32(_jl_type_cache_hash(x)))
    end
    return getfield(x, s)
end

@noinline function typename(x::TypeEq)
    depwarn_if_not_pure("calling `typename` on `Type` is deprecated. If for detection, use `Base.isType(x)`.", :typename)
    return TypeEq.name
end

@noinline function nameof(x::TypeEq)
    depwarn_if_not_pure("calling `nameof` on `Type` is deprecated. If for detection, use `Base.isType(x)`.", :nameof)
    return :Type
end

@noinline function parentmodule(x::TypeEq)
    depwarn_if_not_pure("calling `parentmodule` on `Type` is deprecated. If for detection, use `Base.isType(x)`.", :parentmodule)
    return Core
end

@noinline function isabstracttype(x::TypeEq)
    depwarn_if_not_pure("calling `isabstracttype` on a `Type{...}` is deprecated; `Type{}` is now a kind. If for detection, use `Base.isType(x)`.", :isabstracttype)
    return true
end

@noinline function getproperty(x::Core.TypeEgal, s::Symbol)
    if s === :parameters
        depwarn_if_not_pure("accessing `Type.parameters` is deprecated; use `Base.type_parameter(x)` instead", :getproperty)
        return Core.svec(type_parameter(x))
    elseif s === :name
        depwarn_if_not_pure("accessing `Type.name` is deprecated without replacement. If for detection, use `Base.isType(x)`.", :getproperty)
        return TypeEq.name
    elseif s === :hash
        depwarn_if_not_pure("accessing `Type.hash` is deprecated; use `Base._jl_type_cache_hash(x)` instead", :getproperty)
        return reinterpret(Int32, UInt32(_jl_type_cache_hash(x)))
    end
    return getfield(x, s)
end

@noinline function typename(x::Core.TypeEgal)
    depwarn_if_not_pure("calling `typename` on `Type` is deprecated. If for detection, use `Base.isType(x)`.", :typename)
    return TypeEq.name
end

@noinline function nameof(x::Core.TypeEgal)
    depwarn_if_not_pure("calling `nameof` on `Type` is deprecated. If for detection, use `Base.isType(x)`.", :nameof)
    return :Type
end

@noinline function parentmodule(x::Core.TypeEgal)
    depwarn_if_not_pure("calling `parentmodule` on `Type` is deprecated. If for detection, use `Base.isType(x)`.", :parentmodule)
    return Core
end

@noinline function isabstracttype(x::Core.TypeEgal)
    depwarn_if_not_pure("calling `isabstracttype` on a `Type{...}` is deprecated; `Type{}` is now a kind. If for detection, use `Base.isType(x)`.", :isabstracttype)
    return true
end

@deprecate SubString{T}(s::T, i::Int, j::Int, ::Val{:noshift}) where {T <: AbstractString} begin
    @boundscheck if !(i == j == 0)
        si, sj = i + 1, prevind(s, j + i + 1)
        @inbounds isvalid(s, si) || string_index_err(s, si)
        @inbounds isvalid(s, sj) || string_index_err(s, sj)
    end
    @inbounds raw_substring(s, i + 1, j)
end

# This method is slightly different because it returns a SubString{SubString},
# therefore it requires an explicit SubString{T}(ss) call at the end.
# We discourage creating substrings of substrings, but the deprecated method
# allowed it.
@deprecate SubString{T}(s::T, i::Int, j::Int, ::Val{:noshift}) where {T <: SubString} begin
    @boundscheck if !(i == j == 0)
        si, sj = i + 1, prevind(s, j + i + 1)
        @inbounds isvalid(s, si) || string_index_err(s, si)
        @inbounds isvalid(s, sj) || string_index_err(s, sj)
    end
    ss = @inbounds raw_substring(s, i + 1, j)
    SubString{T}(ss)
end

# `a[] = v` on a `Threads.Atomic` (the `setindex!` form) is a footgun: read-modify-write
# expressions such as `a[] += 1` look atomic but expand to a separate non-atomic load and
# store. Steer users to the explicit `@atomic` form. This is written by hand rather than
# with `@deprecate` so the message can name the hazard and avoid the macro-expansion
# artifact `@deprecate` would embed in the suggested replacement.
# ## This is not yet enabled (deprecated) due to the need to transition a couple stdlibs to this form (or another equivalent form).
function setindex!(x::Threads.Atomic, v)
    # depwarn(lazy"`a[] = v` on a `Threads.Atomic` is deprecated because read-modify-write uses like `a[] += 1` are not atomic; use `@atomic a[] = v` (or `@atomic a[] += 1`, `Threads.atomic_add!`, ...) instead.", :setindex!)
    return @atomic x[] = v
end

# END 1.14 deprecations
