change identity comparisons to use isequal

it would now be possible to make == with non-comparable items an error
since these notions are no longer coupled

fix JuliaLang#9381
ref JuliaLang#15983

base/LineEdit.jl

@@ -1494,11 +1494,11 @@ activate(m::ModalInterface, s::MIState, termbuf, term::TextTerminal) =
 
 commit_changes(t::UnixTerminal, termbuf) = write(t, takebuf_array(termbuf.out_stream))
 function transition(f::Function, s::MIState, mode)
-    if mode == :abort
+    if mode === :abort
         s.aborted = true
         return
     end
-    if mode == :reset
+    if mode === :reset
         reset_state(s)
         return
     end
@@ -1599,16 +1599,16 @@ function prompt!(term, prompt, s = init_state(term, prompt))
                 warn(e)
                 state = :done
             end
-            if state == :abort
+            if state === :abort
                 return buffer(s), false, false
-            elseif state == :done
+            elseif state === :done
                 return buffer(s), true, false
-            elseif state == :suspend
+            elseif state === :suspend
                 if is_unix()
                     return buffer(s), true, true
                 end
             else
-                @assert state == :ok
+                @assert state === :ok
             end
         end
     finally

base/REPL.jl

@@ -377,7 +377,7 @@ end
 function mode_idx(hist::REPLHistoryProvider, mode)
     c = :julia
     for (k,v) in hist.mode_mapping
-        v == mode && (c = k)
+        isequal(v, mode) && (c = k)
     end
     return c
 end
@@ -387,7 +387,7 @@ function add_history(hist::REPLHistoryProvider, s)
     isempty(strip(str)) && return
     mode = mode_idx(hist, LineEdit.mode(s))
     !isempty(hist.history) &&
-        mode == hist.modes[end] && str == hist.history[end] && return
+        isequal(mode, hist.modes[end]) && str == hist.history[end] && return
     push!(hist.modes, mode)
     push!(hist.history, str)
     hist.history_file === nothing && return
@@ -457,13 +457,13 @@ function history_prev(s::LineEdit.MIState, hist::REPLHistoryProvider,
         save_idx::Int = hist.cur_idx)
     hist.last_idx = -1
     m = history_move(s, hist, hist.cur_idx-1, save_idx)
-    if m == :ok
+    if m === :ok
         LineEdit.move_input_start(s)
         LineEdit.reset_key_repeats(s) do
             LineEdit.move_line_end(s)
         end
         LineEdit.refresh_line(s)
-    elseif m == :skip
+    elseif m === :skip
         hist.cur_idx -= 1
         history_prev(s, hist, save_idx)
     else
@@ -481,10 +481,10 @@ function history_next(s::LineEdit.MIState, hist::REPLHistoryProvider,
         hist.last_idx = -1
     end
     m = history_move(s, hist, cur_idx+1, save_idx)
-    if m == :ok
+    if m === :ok
         LineEdit.move_input_end(s)
         LineEdit.refresh_line(s)
-    elseif m == :skip
+    elseif m === :skip
         hist.cur_idx += 1
         history_next(s, hist, save_idx)
     else
@@ -508,7 +508,7 @@ function history_move_prefix(s::LineEdit.PrefixSearchState,
     for idx in idxs
         if (idx == max_idx) || (startswith(hist.history[idx], prefix) && (hist.history[idx] != cur_response || hist.modes[idx] != LineEdit.mode(s)))
             m = history_move(s, hist, idx)
-            if m == :ok
+            if m === :ok
                 if idx == max_idx
                     # on resuming the in-progress edit, leave the cursor where the user last had it
                 elseif isempty(prefix)
@@ -520,7 +520,7 @@ function history_move_prefix(s::LineEdit.PrefixSearchState,
                 end
                 LineEdit.refresh_line(s)
                 return :ok
-            elseif m == :skip
+            elseif m === :skip
                 return history_move_prefix(s,hist,prefix,backwards,idx)
             end
         end

base/array.jl

@@ -653,7 +653,7 @@ end
 function lexcmp(a::Array{UInt8,1}, b::Array{UInt8,1})
     c = ccall(:memcmp, Int32, (Ptr{UInt8}, Ptr{UInt8}, UInt),
               a, b, min(length(a),length(b)))
-    c < 0 ? -1 : c > 0 ? +1 : cmp(length(a),length(b))
+    return c < 0 ? -1 : c > 0 ? +1 : cmp(length(a),length(b))
 end
 
 function reverse(A::AbstractVector, s=1, n=length(A))
@@ -667,7 +667,7 @@ function reverse(A::AbstractVector, s=1, n=length(A))
     for i = n+1:length(A)
         B[i] = A[i]
     end
-    B
+    return B
 end
 reverseind(a::AbstractVector, i::Integer) = length(a) + 1 - i
 
@@ -683,7 +683,7 @@ function reverse!(v::AbstractVector, s=1, n=length(v))
         v[i], v[r] = v[r], v[i]
         r -= 1
     end
-    v
+    return v
 end
 
 function vcat{T}(arrays::Vector{T}...)
@@ -715,7 +715,7 @@ function hcat{T}(V::Vector{T}...)
             throw(DimensionMismatch("vectors must have same lengths"))
         end
     end
-    [ V[j][i]::T for i=1:length(V[1]), j=1:length(V) ]
+    return [ V[j][i]::T for i=1:length(V[1]), j=1:length(V) ]
 end
 
 hcat(A::Matrix...) = typed_hcat(promote_eltype(A...), A...)
@@ -743,7 +743,7 @@ findfirst(A) = findnext(A, 1)
 # returns the index of the next matching element
 function findnext(A, v, start::Integer)
     for i = start:length(A)
-        if A[i] == v
+        if isequal(A[i], v)
             return i
         end
     end
@@ -767,25 +767,27 @@ function findprev(A, start::Integer)
     for i = start:-1:1
         A[i] != 0 && return i
     end
-    0
+    return 0
 end
 findlast(A) = findprev(A, length(A))
 
 # returns the index of the matching element, or 0 if no matching
 function findprev(A, v, start::Integer)
     for i = start:-1:1
-        A[i] == v && return i
+        isequal(A[i], v) && return i
     end
-    0
+    return 0
 end
 findlast(A, v) = findprev(A, v, length(A))
 
 # returns the index of the previous element for which the function returns true, or zero if it never does
 function findprev(testf::Function, A, start::Integer)
     for i = start:-1:1
-        testf(A[i]) && return i
+        if testf(A[i])
+            return i
+        end
     end
-    0
+    return 0
 end
 findlast(testf::Function, A) = findprev(testf, A, length(A))
 
@@ -800,7 +802,7 @@ function find(testf::Function, A)
     end
     I = Array{Int}(length(tmpI))
     copy!(I, tmpI)
-    I
+    return I
 end
 
 function find(A)

base/cartesian.jl

@@ -385,8 +385,8 @@ function exprresolve(ex::Expr)
     can_eval, result = exprresolve_arith(ex)
     if can_eval
         return result
-    elseif ex.head == :call && (ex.args[1] == :+ || ex.args[1] == :-) && length(ex.args) == 3 && ex.args[3] == 0
-        # simplify x+0 and x-0
+    elseif ex.head == :call && (ex.args[1] === :+ || ex.args[1] === :-) && length(ex.args) == 3 && isequal(ex.args[3], 0)
+        # simplify x + 0 and x - 0
         return ex.args[2]
     end
     # Resolve array references

base/dates/io.jl

@@ -116,9 +116,17 @@ function DateFormat(f::AbstractString, locale::AbstractString="english")
         last_offset = m.offset + width
     end
 
-    tran = last_offset > endof(f) ? r"(?=\s|$)" : replace(f[last_offset:end], r"\\(.)", s"\1")
     if !isempty(params)
-        slot = tran == "" ? FixedWidthSlot(params...) : DelimitedSlot(params..., tran)
+        if last_offset > endof(f)
+            slot = DelimitedSlot(params..., r"(?=\s|$)")
+        else
+            tran = replace(f[last_offset:end], r"\\(.)", s"\1")
+            if tran == ""
+                slot = FixedWidthSlot(params...)
+            else
+                slot = DelimitedSlot(params..., tran)
+            end
+        end
         push!(slots,slot)
     end
 

base/dict.jl

@@ -6,18 +6,10 @@ const secret_table_token = :__c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
 
 haskey(d::Associative, k) = in(k,keys(d))
 
-function in(p::Pair, a::Associative, valcmp=(==))
-    v = get(a,p[1],secret_table_token)
+function in(p::Pair, a::Associative, valcmp=isequal)
+    v = get(a, p[1], secret_table_token)
     if !is(v, secret_table_token)
-        if valcmp === is
-            is(v, p[2]) && return true
-        elseif valcmp === (==)
-            ==(v, p[2]) && return true
-        elseif valcmp === isequal
-            isequal(v, p[2]) && return true
-        else
-            valcmp(v, p[2]) && return true
-        end
+        valcmp(v, p[2]) && return true
     end
     return false
 end
@@ -30,7 +22,7 @@ end
 
 function summary(t::Associative)
     n = length(t)
-    string(typeof(t), " with ", n, (n==1 ? " entry" : " entries"))
+    return string(typeof(t), " with ", n, (n==1 ? " entry" : " entries"))
 end
 
 function _truncate_at_width_or_chars(str, width, chars="", truncmark="…")
@@ -960,19 +952,11 @@ ImmutableDict
 ImmutableDict{K,V}(KV::Pair{K,V}) = ImmutableDict{K,V}(KV[1], KV[2])
 ImmutableDict{K,V}(t::ImmutableDict{K,V}, KV::Pair) = ImmutableDict{K,V}(t, KV[1], KV[2])
 
-function in(key_value::Pair, dict::ImmutableDict, valcmp=(==))
+function in(key_value::Pair, dict::ImmutableDict, valcmp=isequal)
     key, value = key_value
     while isdefined(dict, :parent)
-        if dict.key == key
-            if valcmp === is
-                is(value, dict.value) && return true
-            elseif valcmp === (==)
-                ==(value, dict.value) && return true
-            elseif valcmp === isequal
-                isequal(value, dict.value) && return true
-            else
-                valcmp(value, dict.value) && return true
-            end
+        if isequal(dict.key, key)
+            valcmp(value, dict.value) && return true
         end
         dict = dict.parent
     end

base/docs/Docs.jl

@@ -392,8 +392,8 @@ const keywords = Dict{Symbol, DocStr}()
 isdoc(s::AbstractString) = true
 
 isdoc(x) = isexpr(x, :string) ||
-    (isexpr(x, :macrocall) && x.args[1] == Symbol("@doc_str")) ||
-    (isexpr(x, :call) && x.args[1] == Base.Markdown.doc_str)
+    (isexpr(x, :macrocall) && x.args[1] === Symbol("@doc_str")) ||
+    (isexpr(x, :call) && x.args[1] === Base.Markdown.doc_str)
 
 function unblock(ex)
     isexpr(ex, :block) || return ex

base/docs/utils.jl

@@ -141,7 +141,7 @@ function repl(s::Symbol)
     end
 end
 
-isregex(x) = isexpr(x, :macrocall, 2) && x.args[1] == Symbol("@r_str") && !isempty(x.args[2])
+isregex(x) = isexpr(x, :macrocall, 2) && x.args[1] === Symbol("@r_str") && !isempty(x.args[2])
 
 repl(ex::Expr) = isregex(ex) ? :(apropos($ex)) : _repl(ex)
 
@@ -154,7 +154,7 @@ function _repl(x)
     if isexpr(x, :call)
         # Handles function call syntax where each argument is an atom (symbol, number, etc.)
         t = Base.gen_call_with_extracted_types(doc, x)
-        (isexpr(t, :call, 3) && t.args[1] == doc) && (docs = t)
+        (isexpr(t, :call, 3) && t.args[1] === doc) && (docs = t)
     end
     if isfield(x)
         quote

base/exports.jl

@@ -76,6 +76,7 @@ export
     Irrational,
     Matrix,
     MergeSort,
+    NotComparableError,
     NTuple,
     Nullable,
     ObjectIdDict,

base/inference.jl

@@ -2930,10 +2930,10 @@ function inlining_pass(e::Expr, sv, linfo)
             basenumtype = Union{corenumtype, Main.Base.Complex64, Main.Base.Complex128, Main.Base.Rational}
             if isa(a1,basenumtype) || ((isa(a1,Symbol) || isa(a1,Slot) || isa(a1,SSAValue)) &&
                                        exprtype(a1,sv) ⊑ basenumtype)
-                if e.args[3]==2
+                if isequal(e.args[3], 2)
                     e.args = Any[GlobalRef(Main.Base,:*), a1, a1]
                     f = Main.Base.:*; ft = abstract_eval_constant(f)
-                elseif e.args[3]==3
+                elseif isequal(e.args[3], 3)
                     e.args = Any[GlobalRef(Main.Base,:*), a1, a1, a1]
                     f = Main.Base.:*; ft = abstract_eval_constant(f)
                 end
@@ -3171,7 +3171,7 @@ end
 # boundscheck context in the method body
 function inbounds_meta_elim_pass!(code::Array{Any,1})
     if findfirst(x -> isa(x, Expr) &&
-                      ((x.head === :inbounds && x.args[1] == true) || x.head === :boundscheck),
+                      ((x.head === :inbounds && x.args[1] === true) || x.head === :boundscheck),
                  code) == 0
         filter!(x -> !(isa(x, Expr) && x.head === :inbounds), code)
     end

base/multidimensional.jl

@@ -628,7 +628,7 @@ end
 end
 @generated function _unsafe_setindex!(B::BitArray, X::Union{BitArray,Array}, I0::Union{Colon,UnitRange{Int}}, I::Union{Int,UnitRange{Int},Colon}...)
     N = length(I)
-    rangeexp = [I[d] == Colon ? :(1:size(B, $(d+1))) : :(I[$d]) for d = 1:N]
+    rangeexp = [I[d] === Colon ? :(1:size(B, $(d+1))) : :(I[$d]) for d = 1:N]
     quote
         idxlens = @ncall $N index_lengths B I0 d->I[d]
         @ncall $N setindex_shape_check X idxlens[1] d->idxlens[d+1]
@@ -667,7 +667,7 @@ end
 end
 @generated function _unsafe_setindex!(B::BitArray, x, I0::Union{Colon,UnitRange{Int}}, I::Union{Int,UnitRange{Int},Colon}...)
     N = length(I)
-    rangeexp = [I[d] == Colon ? :(1:size(B, $(d+1))) : :(I[$d]) for d = 1:N]
+    rangeexp = [I[d] === Colon ? :(1:size(B, $(d+1))) : :(I[$d]) for d = 1:N]
     quote
         y = Bool(x)
         idxlens = @ncall $N index_lengths B I0 d->I[d]

base/operators.jl

@@ -8,9 +8,15 @@ supertype(T::DataType) = T.super
 
 ## generic comparison ##
 
-==(x,y) = x === y
-
-isequal(x, y) = x == y
+=={T}(x::T, y::T) = x === y
+immutable NotComparableError <: Exception end
+const NotComparable = NotComparableError()
+==(x::ANY, y::ANY) = NotComparable
+!(e::NotComparableError) = throw(e)
+# immutable NotComparableError; a; b; end
+# ==(x::ANY, y::ANY) = NotComparableError(x, y)
+
+isequal(x, y) = (x == y) === true
 isequal(x::AbstractFloat, y::AbstractFloat) = (isnan(x) & isnan(y)) | (signbit(x) == signbit(y)) & (x == y)
 isequal(x::Real,          y::AbstractFloat) = (isnan(x) & isnan(y)) | (signbit(x) == signbit(y)) & (x == y)
 isequal(x::AbstractFloat, y::Real         ) = (isnan(x) & isnan(y)) | (signbit(x) == signbit(y)) & (x == y)

base/parse.jl

@@ -176,11 +176,11 @@ function parse(str::AbstractString, pos::Int; greedy::Bool=true, raise::Bool=tru
     if raise && isa(ex,Expr) && is(ex.head,:error)
         throw(ParseError(ex.args[1]))
     end
-    if ex == ()
+    if ex === ()
         raise && throw(ParseError("end of input"))
         ex = Expr(:error, "end of input")
     end
-    ex, pos+1 # C is zero-based, Julia is 1-based
+    return ex, pos+1 # C is zero-based, Julia is 1-based
 end
 
 function parse(str::AbstractString; raise::Bool=true)