From 6ee12e0b49b19aa636df3389d9dd062e200f7e1f Mon Sep 17 00:00:00 2001
From: Sebastian Stock <42280794+sostock@users.noreply.github.com>
Date: Mon, 17 Jun 2019 19:00:07 +0200
Subject: [PATCH 1/7] Make empty ranges equal

---
 base/range.jl        | 10 ++++++----
 base/strings/util.jl |  8 ++++----
 test/ranges.jl       |  4 +++-
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/base/range.jl b/base/range.jl
index 9fbc198d1c372..3c73ca1bbe07f 100644
--- a/base/range.jl
+++ b/base/range.jl
@@ -714,18 +714,20 @@ show(io::IO, r::UnitRange) = print(io, repr(first(r)), ':', repr(last(r)))
 show(io::IO, r::OneTo) = print(io, "Base.OneTo(", r.stop, ")")
 
 ==(r::T, s::T) where {T<:AbstractRange} =
-    (first(r) == first(s)) & (step(r) == step(s)) & (last(r) == last(s))
+    (isempty(r) & isempty(s)) | ((first(r) == first(s)) & (step(r) == step(s)) & (last(r) == last(s)))
 ==(r::OrdinalRange, s::OrdinalRange) =
-    (first(r) == first(s)) & (step(r) == step(s)) & (last(r) == last(s))
+    (isempty(r) & isempty(s)) | ((first(r) == first(s)) & (step(r) == step(s)) & (last(r) == last(s)))
 ==(r::T, s::T) where {T<:Union{StepRangeLen,LinRange}} =
-    (first(r) == first(s)) & (length(r) == length(s)) & (last(r) == last(s))
+    (isempty(r) & isempty(s)) | ((first(r) == first(s)) & (length(r) == length(s)) & (last(r) == last(s)))
 ==(r::Union{StepRange{T},StepRangeLen{T,T}}, s::Union{StepRange{T},StepRangeLen{T,T}}) where {T} =
-    (first(r) == first(s)) & (last(r) == last(s)) & (step(r) == step(s))
+    (isempty(r) & isempty(s)) | ((first(r) == first(s)) & (step(r) == step(s)) & (last(r) == last(s)))
 
 function ==(r::AbstractRange, s::AbstractRange)
     lr = length(r)
     if lr != length(s)
         return false
+    elseif iszero(lr)
+        return true
     end
     yr, ys = iterate(r), iterate(s)
     while yr !== nothing
diff --git a/base/strings/util.jl b/base/strings/util.jl
index b97a76a24b3e8..ad2e8b54a72e6 100644
--- a/base/strings/util.jl
+++ b/base/strings/util.jl
@@ -324,8 +324,8 @@ end
 function _split(str::AbstractString, splitter, limit::Integer, keepempty::Bool, strs::Array)
     i = 1 # firstindex(str)
     n = lastindex(str)
-    r = something(findfirst(splitter,str), 0)
-    if r != 0:-1
+    r = findfirst(splitter,str)
+    if !isnothing(r)
         j, k = first(r), nextind(str,last(r))
         while 0 < j <= n && length(strs) != limit-1
             if i < k
@@ -335,8 +335,8 @@ function _split(str::AbstractString, splitter, limit::Integer, keepempty::Bool,
                 i = k
             end
             (k <= j) && (k = nextind(str,j))
-            r = something(findnext(splitter,str,k), 0)
-            r == 0:-1 && break
+            r = findnext(splitter,str,k)
+            isnothing(r) && break
             j, k = first(r), nextind(str,last(r))
         end
     end
diff --git a/test/ranges.jl b/test/ranges.jl
index 38c73b1bef792..5ab735ffc782b 100644
--- a/test/ranges.jl
+++ b/test/ranges.jl
@@ -765,7 +765,8 @@ end
                        map(Int32,1:3:17), map(Int64,1:3:17), 1:0, 1:-1:0, 17:-3:0,
                        0.0:0.1:1.0, map(Float32,0.0:0.1:1.0),map(Float32,LinRange(0.0, 1.0, 11)),
                        1.0:eps():1.0 .+ 10eps(), 9007199254740990.:1.0:9007199254740994,
-                       range(0, stop=1, length=20), map(Float32, range(0, stop=1, length=20))]
+                       range(0, stop=1, length=20), map(Float32, range(0, stop=1, length=20)),
+                       3:2, 5:-2:7, range(0.0, step=2.0, length=0), 3//2:3//2:0//1, LinRange(2,3,0)]
     for r in Rs
         local r
         ar = Vector(r)
@@ -785,6 +786,7 @@ end
     @test 1:1:10 == 1:10 == 1:10 == Base.OneTo(10) == Base.OneTo(10)
     @test 1:10 != 2:10 != 2:11 != Base.OneTo(11)
     @test Base.OneTo(10) != Base.OneTo(11) != 1:10
+    @test Base.OneTo(0) == 5:4
 end
 # issue #2959
 @test 1.0:1.5 == 1.0:1.0:1.5 == 1.0:1.0

From aa604605f5f0d9c496209190ea600c859933ac13 Mon Sep 17 00:00:00 2001
From: Sebastian Stock <42280794+sostock@users.noreply.github.com>
Date: Thu, 20 Jun 2019 16:57:36 +0200
Subject: [PATCH 2/7] Adapt tests to new range comparison behavior

---
 stdlib/Dates/test/ranges.jl         |  8 +++----
 stdlib/REPL/test/replcompletions.jl | 15 ++++++++-----
 test/core.jl                        |  2 +-
 test/ranges.jl                      |  8 +++----
 test/regex.jl                       |  4 ++--
 test/sorting.jl                     | 34 +++++++++++++++++------------
 test/strings/search.jl              |  6 ++---
 7 files changed, 44 insertions(+), 33 deletions(-)

diff --git a/stdlib/Dates/test/ranges.jl b/stdlib/Dates/test/ranges.jl
index 473940d1ce98b..b21ae01195386 100644
--- a/stdlib/Dates/test/ranges.jl
+++ b/stdlib/Dates/test/ranges.jl
@@ -35,7 +35,7 @@ let
                 @test first(reverse(dr)) < f1
                 @test last(reverse(dr)) >= f1
                 @test issorted(dr)
-                @test sortperm(dr) == 1:1:0
+                @test sortperm(dr) === 1:1:0
                 @test !(f1 in dr)
                 @test !(l1 in dr)
                 @test !(f1 - pos_step in dr)
@@ -93,7 +93,7 @@ let
                 @test first(reverse(dr)) > l1
                 @test last(reverse(dr)) <= l1
                 @test issorted(dr)
-                @test sortperm(dr) == 1:1:0
+                @test sortperm(dr) === 1:1:0
                 @test !(l1 in dr)
                 @test !(l1 in dr)
                 @test !(l1 - neg_step in dr)
@@ -153,7 +153,7 @@ let
                     @test first(reverse(dr)) < f1
                     @test last(reverse(dr)) >= f1
                     @test issorted(dr)
-                    @test sortperm(dr) == 1:1:0
+                    @test sortperm(dr) === 1:1:0
                     @test !(f1 in dr)
                     @test !(l1 in dr)
                     @test !(f1 - pos_step in dr)
@@ -211,7 +211,7 @@ let
                     @test first(reverse(dr)) > l1
                     @test last(reverse(dr)) <= l1
                     @test issorted(dr)
-                    @test sortperm(dr) == 1:1:0
+                    @test sortperm(dr) === 1:1:0
                     @test !(l1 in dr)
                     @test !(l1 in dr)
                     @test !(l1 - neg_step in dr)
diff --git a/stdlib/REPL/test/replcompletions.jl b/stdlib/REPL/test/replcompletions.jl
index 5f3d9e9e57c19..f2628ee3cf4a9 100644
--- a/stdlib/REPL/test/replcompletions.jl
+++ b/stdlib/REPL/test/replcompletions.jl
@@ -126,7 +126,7 @@ end
 let s = "Main.CompletionFoo."
     c, r = test_complete(s)
     @test "bar" in c
-    @test r == 20:19
+    @test r === 20:19
     @test s[r] == ""
 end
 
@@ -550,7 +550,12 @@ end
 
 # The return type is of importance, before #8995 it would return nothing
 # which would raise an error in the repl code.
-@test (String[], 0:-1, false) == test_scomplete("\$a")
+let c, r, res
+    c, r, res = test_scomplete("\$a")
+    @test c == String[]
+    @test r === 0:-1
+    @test res === false
+end
 
 if Sys.isunix()
 let s, c, r
@@ -598,7 +603,7 @@ let s, c, r
         s = "/tmp/"
         c,r = test_scomplete(s)
         @test !("tmp/" in c)
-        @test r == 6:5
+        @test r === 6:5
         @test s[r] == ""
     end
 
@@ -615,7 +620,7 @@ let s, c, r
         file = joinpath(path, "repl completions")
         s = "/tmp "
         c,r = test_scomplete(s)
-        @test r == 6:5
+        @test r === 6:5
     end
 
     # Test completing paths with an escaped trailing space
@@ -929,7 +934,7 @@ end
 let s = ""
     c, r = test_complete_context(s)
     @test "bar" in c
-    @test r == 1:0
+    @test r === 1:0
     @test s[r] == ""
 end
 
diff --git a/test/core.jl b/test/core.jl
index 14375439ebfee..b883636b380de 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -6701,7 +6701,7 @@ function f27597(y)
     return y
 end
 @test f27597([1]) == [1]
-@test f27597([]) == 1:0
+@test f27597([]) === 1:0
 
 # issue #22291
 wrap22291(ind) = (ind...,)
diff --git a/test/ranges.jl b/test/ranges.jl
index 5ab735ffc782b..052603b55893e 100644
--- a/test/ranges.jl
+++ b/test/ranges.jl
@@ -422,10 +422,10 @@ end
     end
 end
 @testset "indexing range with empty range (#4309)" begin
-    @test (3:6)[5:4] == 7:6
+    @test (3:6)[5:4] === 7:6
     @test_throws BoundsError (3:6)[5:5]
     @test_throws BoundsError (3:6)[5]
-    @test (0:2:10)[7:6] == 12:2:10
+    @test (0:2:10)[7:6] === 12:2:10
     @test_throws BoundsError (0:2:10)[7:7]
 end
 # indexing with negative ranges (#8351)
@@ -1479,11 +1479,11 @@ end
         for stops in [-2, 0, 2, 100]
             for lengths in [2, 10, 100]
                 if stops >= starts
-                    @test range(starts, stops, length=lengths) == range(starts, stop=stops, length=lengths)
+                    @test range(starts, stops, length=lengths) === range(starts, stop=stops, length=lengths)
                 end
             end
             for steps in [0.01, 1, 2]
-                @test range(starts, stops, step=steps) == range(starts, stop=stops, step=steps)
+                @test range(starts, stops, step=steps) === range(starts, stop=stops, step=steps)
             end
         end
     end
diff --git a/test/regex.jl b/test/regex.jl
index aad5413fd250b..7732b4a9ddafa 100644
--- a/test/regex.jl
+++ b/test/regex.jl
@@ -49,8 +49,8 @@
     # findall:
     @test findall(r"\w+", "foo bar") == [1:3, 5:7]
     @test findall(r"\w+", "foo bar", overlap=true) == [1:3, 2:3, 3:3, 5:7, 6:7, 7:7]
-    @test findall(r"\w*", "foo bar") == [1:3, 4:3, 5:7, 8:7]
-    @test findall(r"\b", "foo bar") == [1:0, 4:3, 5:4, 8:7]
+    @test all(findall(r"\w*", "foo bar") .=== [1:3, 4:3, 5:7, 8:7]) # use === to compare empty ranges
+    @test all(findall(r"\b", "foo bar") .=== [1:0, 4:3, 5:4, 8:7])  # use === to compare empty ranges
 
     # Named subpatterns
     let m = match(r"(?<a>.)(.)(?<b>.)", "xyz")
diff --git a/test/sorting.jl b/test/sorting.jl
index 8b58a2d2620ef..ce8c4e868b7cf 100644
--- a/test/sorting.jl
+++ b/test/sorting.jl
@@ -35,6 +35,12 @@ let a=[1:10;]
 end
 @test sum(randperm(6)) == 21
 
+# Compare ranges by comparing their `first` and `last` elements and their `length`. This
+# returns `false` if empty ranges have different startpoints, which is relevant for
+# `searchsorted`
+==ᵣ(r::AbstractRange, s::AbstractRange) =
+    (first(r) == first(s)) & (length(r) == length(s)) & (last(r) == last(s))
+
 @testset "searchsorted" begin
     numTypes = [ Int8,  Int16,  Int32,  Int64,  Int128,
                 UInt8, UInt16, UInt32, UInt64, UInt128,
@@ -46,16 +52,16 @@ end
     @test searchsorted(fill(1, 15), 1, 6, 10, Forward) == 6:10
 
     for R in numTypes, T in numTypes
-        @test searchsorted(R[1, 1, 2, 2, 3, 3], T(0)) == 1:0
+        @test searchsorted(R[1, 1, 2, 2, 3, 3], T(0)) === 1:0
         @test searchsorted(R[1, 1, 2, 2, 3, 3], T(1)) == 1:2
         @test searchsorted(R[1, 1, 2, 2, 3, 3], T(2)) == 3:4
-        @test searchsorted(R[1, 1, 2, 2, 3, 3], T(4)) == 7:6
-        @test searchsorted(R[1, 1, 2, 2, 3, 3], 2.5) == 5:4
+        @test searchsorted(R[1, 1, 2, 2, 3, 3], T(4)) === 7:6
+        @test searchsorted(R[1, 1, 2, 2, 3, 3], 2.5) === 5:4
 
-        @test searchsorted(1:3, T(0)) == 1:0
+        @test searchsorted(1:3, T(0)) ==ᵣ 1:0
         @test searchsorted(1:3, T(1)) == 1:1
         @test searchsorted(1:3, T(2)) == 2:2
-        @test searchsorted(1:3, T(4)) == 4:3
+        @test searchsorted(1:3, T(4)) ==ᵣ 4:3
 
         @test searchsorted(R[1:10;], T(1), by=(x -> x >= 5)) == 1:4
         @test searchsorted(R[1:10;], T(10), by=(x -> x >= 5)) == 5:10
@@ -67,31 +73,31 @@ end
         rg_r = reverse(rg)
         rgv, rgv_r = [rg;], [rg_r;]
         for i = I
-            @test searchsorted(rg,i) == searchsorted(rgv,i)
-            @test searchsorted(rg_r,i,rev=true) == searchsorted(rgv_r,i,rev=true)
+            @test searchsorted(rg,i) === searchsorted(rgv,i)
+            @test searchsorted(rg_r,i,rev=true) === searchsorted(rgv_r,i,rev=true)
         end
     end
 
     rg = 0.0:0.01:1.0
     for i = 2:101
         @test searchsorted(rg, rg[i]) == i:i
-        @test searchsorted(rg, prevfloat(rg[i])) == i:i-1
-        @test searchsorted(rg, nextfloat(rg[i])) == i+1:i
+        @test searchsorted(rg, prevfloat(rg[i])) === i:i-1
+        @test searchsorted(rg, nextfloat(rg[i])) === i+1:i
     end
 
     rg_r = reverse(rg)
     for i = 1:100
         @test searchsorted(rg_r, rg_r[i], rev=true) == i:i
-        @test searchsorted(rg_r, prevfloat(rg_r[i]), rev=true) == i+1:i
-        @test searchsorted(rg_r, nextfloat(rg_r[i]), rev=true) == i:i-1
+        @test searchsorted(rg_r, prevfloat(rg_r[i]), rev=true) === i+1:i
+        @test searchsorted(rg_r, nextfloat(rg_r[i]), rev=true) === i:i-1
     end
 
     @test searchsorted(1:10, 1, by=(x -> x >= 5)) == searchsorted([1:10;], 1, by=(x -> x >= 5))
     @test searchsorted(1:10, 10, by=(x -> x >= 5)) == searchsorted([1:10;], 10, by=(x -> x >= 5))
 
-    @test searchsorted([], 0) == 1:0
-    @test searchsorted([1,2,3], 0) == 1:0
-    @test searchsorted([1,2,3], 4) == 4:3
+    @test searchsorted([], 0) === 1:0
+    @test searchsorted([1,2,3], 0) === 1:0
+    @test searchsorted([1,2,3], 4) === 4:3
 
     @testset "issue 8866" begin
         @test searchsortedfirst(500:1.0:600, -1.0e20) == 1
diff --git a/test/strings/search.jl b/test/strings/search.jl
index 8de73e5c652e5..ff0fbf05d770b 100644
--- a/test/strings/search.jl
+++ b/test/strings/search.jl
@@ -247,7 +247,7 @@ end
 for i = 1:lastindex(u8str)
     @test findnext("", u8str, i) == i:i-1
 end
-@test findfirst("", "") == 1:0
+@test findfirst("", "") === 1:0
 
 # string backward search with a zero-char string
 for i = 1:lastindex(astr)
@@ -256,7 +256,7 @@ end
 for i = 1:lastindex(u8str)
     @test findprev("", u8str, i) == i:i-1
 end
-@test findlast("", "") == 1:0
+@test findlast("", "") === 1:0
 
 # string forward search with a zero-char regex
 for i = 1:lastindex(astr)
@@ -377,7 +377,7 @@ s_18109 = "fooα🐨βcd3"
 @testset "findall" begin
     @test findall("fooo", "foo") == UnitRange{Int}[]
     @test findall("ing", "Spinning laughing dancing") == [6:8, 15:17, 23:25]
-    @test findall("", "foo") == [1:0, 2:1, 3:2, 4:3]
+    @test all(findall("", "foo") .=== [1:0, 2:1, 3:2, 4:3]) # use === to compare empty ranges
     @test findall("αβ", "blαh blαβ blαββy") == findall("αβ", "blαh blαβ blαββy", overlap=true) == [9:11, 16:18]
     @test findall("aa", "aaaaaa") == [1:2, 3:4, 5:6]
     @test findall("aa", "aaaaaa", overlap=true) == [1:2, 2:3, 3:4, 4:5, 5:6]

From f3775deb15dd0fc0281b4edd63a13bc9b8f77954 Mon Sep 17 00:00:00 2001
From: Sebastian Stock <42280794+sostock@users.noreply.github.com>
Date: Thu, 20 Jun 2019 20:09:21 +0200
Subject: [PATCH 3/7] Fix tests on 32-bit systems

---
 stdlib/Dates/test/ranges.jl         |  8 ++++----
 stdlib/REPL/test/replcompletions.jl | 15 ++++++++++-----
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/stdlib/Dates/test/ranges.jl b/stdlib/Dates/test/ranges.jl
index b21ae01195386..0535c350ecb32 100644
--- a/stdlib/Dates/test/ranges.jl
+++ b/stdlib/Dates/test/ranges.jl
@@ -35,7 +35,7 @@ let
                 @test first(reverse(dr)) < f1
                 @test last(reverse(dr)) >= f1
                 @test issorted(dr)
-                @test sortperm(dr) === 1:1:0
+                @test sortperm(dr) === Int64(1):Int64(1):Int64(0)
                 @test !(f1 in dr)
                 @test !(l1 in dr)
                 @test !(f1 - pos_step in dr)
@@ -93,7 +93,7 @@ let
                 @test first(reverse(dr)) > l1
                 @test last(reverse(dr)) <= l1
                 @test issorted(dr)
-                @test sortperm(dr) === 1:1:0
+                @test sortperm(dr) === Int64(1):Int64(1):Int64(0)
                 @test !(l1 in dr)
                 @test !(l1 in dr)
                 @test !(l1 - neg_step in dr)
@@ -153,7 +153,7 @@ let
                     @test first(reverse(dr)) < f1
                     @test last(reverse(dr)) >= f1
                     @test issorted(dr)
-                    @test sortperm(dr) === 1:1:0
+                    @test sortperm(dr) === Int64(1):Int64(1):Int64(0)
                     @test !(f1 in dr)
                     @test !(l1 in dr)
                     @test !(f1 - pos_step in dr)
@@ -211,7 +211,7 @@ let
                     @test first(reverse(dr)) > l1
                     @test last(reverse(dr)) <= l1
                     @test issorted(dr)
-                    @test sortperm(dr) === 1:1:0
+                    @test sortperm(dr) === Int64(1):Int64(1):Int64(0)
                     @test !(l1 in dr)
                     @test !(l1 in dr)
                     @test !(l1 - neg_step in dr)
diff --git a/stdlib/REPL/test/replcompletions.jl b/stdlib/REPL/test/replcompletions.jl
index f2628ee3cf4a9..542cf0da2640c 100644
--- a/stdlib/REPL/test/replcompletions.jl
+++ b/stdlib/REPL/test/replcompletions.jl
@@ -95,6 +95,11 @@ test_scomplete(s) =  map_completion_text(shell_completions(s,lastindex(s)))
 test_bslashcomplete(s) =  map_completion_text(bslash_completions(s,lastindex(s))[2])
 test_complete_context(s) =  map_completion_text(completions(s,lastindex(s),Main.CompletionFoo))
 
+# Compare ranges by comparing their `first` and `last` elements and their `length`. This
+# returns `false` if empty ranges have different startpoints.
+==ᵣ(r::AbstractRange, s::AbstractRange) =
+    (first(r) == first(s)) & (length(r) == length(s)) & (last(r) == last(s))
+
 let s = ""
     c, r = test_complete(s)
     @test "CompletionFoo" in c
@@ -126,7 +131,7 @@ end
 let s = "Main.CompletionFoo."
     c, r = test_complete(s)
     @test "bar" in c
-    @test r === 20:19
+    @test r ==ᵣ 20:19
     @test s[r] == ""
 end
 
@@ -553,7 +558,7 @@ end
 let c, r, res
     c, r, res = test_scomplete("\$a")
     @test c == String[]
-    @test r === 0:-1
+    @test r ==ᵣ 0:-1
     @test res === false
 end
 
@@ -603,7 +608,7 @@ let s, c, r
         s = "/tmp/"
         c,r = test_scomplete(s)
         @test !("tmp/" in c)
-        @test r === 6:5
+        @test r ==ᵣ 6:5
         @test s[r] == ""
     end
 
@@ -620,7 +625,7 @@ let s, c, r
         file = joinpath(path, "repl completions")
         s = "/tmp "
         c,r = test_scomplete(s)
-        @test r === 6:5
+        @test r ==ᵣ 6:5
     end
 
     # Test completing paths with an escaped trailing space
@@ -934,7 +939,7 @@ end
 let s = ""
     c, r = test_complete_context(s)
     @test "bar" in c
-    @test r === 1:0
+    @test r ==ᵣ 1:0
     @test s[r] == ""
 end
 

From a0821f45ed614e1d34a703ca7bb537a4728ca9a0 Mon Sep 17 00:00:00 2001
From: Sebastian Stock <42280794+sostock@users.noreply.github.com>
Date: Thu, 20 Jun 2019 21:04:52 +0200
Subject: [PATCH 4/7] Fix tests for Dates

---
 stdlib/Dates/test/ranges.jl | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/stdlib/Dates/test/ranges.jl b/stdlib/Dates/test/ranges.jl
index 0535c350ecb32..4a35c33923a2d 100644
--- a/stdlib/Dates/test/ranges.jl
+++ b/stdlib/Dates/test/ranges.jl
@@ -7,6 +7,11 @@ using Dates
 
 using InteractiveUtils: subtypes
 
+# Compare ranges by comparing their `first` and `last` elements and their `length`. This
+# returns `false` if empty ranges have different startpoints.
+==ᵣ(r::AbstractRange, s::AbstractRange) =
+    (first(r) == first(s)) & (length(r) == length(s)) & (last(r) == last(s))
+
 let
     for T in (Dates.Date, Dates.DateTime)
         f1 = T(2014); l1 = T(2013, 12, 31)
@@ -35,7 +40,7 @@ let
                 @test first(reverse(dr)) < f1
                 @test last(reverse(dr)) >= f1
                 @test issorted(dr)
-                @test sortperm(dr) === Int64(1):Int64(1):Int64(0)
+                @test sortperm(dr) ==ᵣ 1:1:0
                 @test !(f1 in dr)
                 @test !(l1 in dr)
                 @test !(f1 - pos_step in dr)
@@ -93,7 +98,7 @@ let
                 @test first(reverse(dr)) > l1
                 @test last(reverse(dr)) <= l1
                 @test issorted(dr)
-                @test sortperm(dr) === Int64(1):Int64(1):Int64(0)
+                @test sortperm(dr) ==ᵣ 1:1:0
                 @test !(l1 in dr)
                 @test !(l1 in dr)
                 @test !(l1 - neg_step in dr)
@@ -153,7 +158,7 @@ let
                     @test first(reverse(dr)) < f1
                     @test last(reverse(dr)) >= f1
                     @test issorted(dr)
-                    @test sortperm(dr) === Int64(1):Int64(1):Int64(0)
+                    @test sortperm(dr) ==ᵣ 1:1:0
                     @test !(f1 in dr)
                     @test !(l1 in dr)
                     @test !(f1 - pos_step in dr)
@@ -211,7 +216,7 @@ let
                     @test first(reverse(dr)) > l1
                     @test last(reverse(dr)) <= l1
                     @test issorted(dr)
-                    @test sortperm(dr) === Int64(1):Int64(1):Int64(0)
+                    @test sortperm(dr) ==ᵣ 1:1:0
                     @test !(l1 in dr)
                     @test !(l1 in dr)
                     @test !(l1 - neg_step in dr)

From 548b667d40b261d9d38543a5784a2edbfbb72d40 Mon Sep 17 00:00:00 2001
From: Sebastian Stock <42280794+sostock@users.noreply.github.com>
Date: Mon, 1 Jul 2019 19:25:34 +0200
Subject: [PATCH 5/7] Add NEWS.md item for #32348

---
 NEWS.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/NEWS.md b/NEWS.md
index 643eb29aa1526..583c339b6ca8d 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -9,6 +9,7 @@ New language features
 Language changes
 ----------------
 
+* Empty ranges now compare equal, regardless of their startpoint and step ([#32348]).
 
 Multi-threading changes
 -----------------------

From 648c78e474197b784c23c41c0735564e7dca32df Mon Sep 17 00:00:00 2001
From: Sebastian Stock <42280794+sostock@users.noreply.github.com>
Date: Tue, 21 Apr 2020 09:07:29 +0200
Subject: [PATCH 6/7] Update tests

---
 test/offsetarray.jl | 2 +-
 test/sorting.jl     | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/test/offsetarray.jl b/test/offsetarray.jl
index 58a83cc2c9311..7479821be8268 100644
--- a/test/offsetarray.jl
+++ b/test/offsetarray.jl
@@ -502,7 +502,7 @@ v = OffsetArray(rand(8), (-2,))
 @test sort(A, dims=2) == OffsetArray(sort(parent(A), dims=2), A.offsets)
 # Issue #33977
 soa = OffsetArray([2,2,3], -2)
-@test searchsorted(soa, 1) == -1:-2
+@test searchsorted(soa, 1) === -1:-2
 @test searchsortedfirst(soa, 1) == -1
 @test searchsortedlast(soa, 1) == -2
 @test first(sort!(soa; alg=QuickSort)) == 2
diff --git a/test/sorting.jl b/test/sorting.jl
index 99d31962b1c01..f19af948db597 100644
--- a/test/sorting.jl
+++ b/test/sorting.jl
@@ -187,11 +187,11 @@ end
         for v0 = (3:-1:1, 3.0:-1.0:1.0), v = (v0, collect(v0))
             @test searchsorted(v, 3, rev=true) == 1:1
             @test searchsorted(v, 3.0, rev=true) == 1:1
-            @test searchsorted(v, 2.5, rev=true) == 2:1
+            @test searchsorted(v, 2.5, rev=true) === 2:1
             @test searchsorted(v, 2, rev=true) == 2:2
-            @test searchsorted(v, 1.2, rev=true) == 3:2
+            @test searchsorted(v, 1.2, rev=true) === 3:2
             @test searchsorted(v, 1, rev=true) == 3:3
-            @test searchsorted(v, 0.1, rev=true) == 4:3
+            @test searchsorted(v, 0.1, rev=true) === 4:3
         end
     end
 end

From afcaa9c7a6cd47cd7cf0b391b10b67895a287b14 Mon Sep 17 00:00:00 2001
From: Sebastian Stock <42280794+sostock@users.noreply.github.com>
Date: Tue, 28 Apr 2020 13:52:21 +0200
Subject: [PATCH 7/7] Simplify tests

---
 stdlib/Dates/test/ranges.jl         | 13 ++++---------
 stdlib/REPL/test/replcompletions.jl | 15 +++++----------
 test/sorting.jl                     | 10 ++--------
 3 files changed, 11 insertions(+), 27 deletions(-)

diff --git a/stdlib/Dates/test/ranges.jl b/stdlib/Dates/test/ranges.jl
index 4a35c33923a2d..f10350c3cb6f5 100644
--- a/stdlib/Dates/test/ranges.jl
+++ b/stdlib/Dates/test/ranges.jl
@@ -7,11 +7,6 @@ using Dates
 
 using InteractiveUtils: subtypes
 
-# Compare ranges by comparing their `first` and `last` elements and their `length`. This
-# returns `false` if empty ranges have different startpoints.
-==ᵣ(r::AbstractRange, s::AbstractRange) =
-    (first(r) == first(s)) & (length(r) == length(s)) & (last(r) == last(s))
-
 let
     for T in (Dates.Date, Dates.DateTime)
         f1 = T(2014); l1 = T(2013, 12, 31)
@@ -40,7 +35,7 @@ let
                 @test first(reverse(dr)) < f1
                 @test last(reverse(dr)) >= f1
                 @test issorted(dr)
-                @test sortperm(dr) ==ᵣ 1:1:0
+                @test sortperm(dr) === StepRange{Int64,Int}(1:1:0)
                 @test !(f1 in dr)
                 @test !(l1 in dr)
                 @test !(f1 - pos_step in dr)
@@ -98,7 +93,7 @@ let
                 @test first(reverse(dr)) > l1
                 @test last(reverse(dr)) <= l1
                 @test issorted(dr)
-                @test sortperm(dr) ==ᵣ 1:1:0
+                @test sortperm(dr) === StepRange{Int64,Int}(1:1:0)
                 @test !(l1 in dr)
                 @test !(l1 in dr)
                 @test !(l1 - neg_step in dr)
@@ -158,7 +153,7 @@ let
                     @test first(reverse(dr)) < f1
                     @test last(reverse(dr)) >= f1
                     @test issorted(dr)
-                    @test sortperm(dr) ==ᵣ 1:1:0
+                    @test sortperm(dr) === StepRange{Int64,Int}(1:1:0)
                     @test !(f1 in dr)
                     @test !(l1 in dr)
                     @test !(f1 - pos_step in dr)
@@ -216,7 +211,7 @@ let
                     @test first(reverse(dr)) > l1
                     @test last(reverse(dr)) <= l1
                     @test issorted(dr)
-                    @test sortperm(dr) ==ᵣ 1:1:0
+                    @test sortperm(dr) === StepRange{Int64,Int}(1:1:0)
                     @test !(l1 in dr)
                     @test !(l1 in dr)
                     @test !(l1 - neg_step in dr)
diff --git a/stdlib/REPL/test/replcompletions.jl b/stdlib/REPL/test/replcompletions.jl
index 1996c87cf7dcf..d37bfd7f3ad7e 100644
--- a/stdlib/REPL/test/replcompletions.jl
+++ b/stdlib/REPL/test/replcompletions.jl
@@ -101,11 +101,6 @@ test_scomplete(s) =  map_completion_text(shell_completions(s,lastindex(s)))
 test_bslashcomplete(s) =  map_completion_text(bslash_completions(s,lastindex(s))[2])
 test_complete_context(s) =  map_completion_text(completions(s,lastindex(s),Main.CompletionFoo))
 
-# Compare ranges by comparing their `first` and `last` elements and their `length`. This
-# returns `false` if empty ranges have different startpoints.
-==ᵣ(r::AbstractRange, s::AbstractRange) =
-    (first(r) == first(s)) & (length(r) == length(s)) & (last(r) == last(s))
-
 let s = ""
     c, r = test_complete(s)
     @test "CompletionFoo" in c
@@ -137,7 +132,7 @@ end
 let s = "Main.CompletionFoo."
     c, r = test_complete(s)
     @test "bar" in c
-    @test r ==ᵣ 20:19
+    @test r === UnitRange{Int64}(20:19)
     @test s[r] == ""
 end
 
@@ -600,7 +595,7 @@ end
 let c, r, res
     c, r, res = test_scomplete("\$a")
     @test c == String[]
-    @test r ==ᵣ 0:-1
+    @test r === UnitRange{Int64}(0:-1)
     @test res === false
 end
 
@@ -650,7 +645,7 @@ let s, c, r
         s = "/tmp/"
         c,r = test_scomplete(s)
         @test !("tmp/" in c)
-        @test r ==ᵣ 6:5
+        @test r === UnitRange{Int64}(6:5)
         @test s[r] == ""
     end
 
@@ -667,7 +662,7 @@ let s, c, r
         file = joinpath(path, "repl completions")
         s = "/tmp "
         c,r = test_scomplete(s)
-        @test r ==ᵣ 6:5
+        @test r === UnitRange{Int64}(6:5)
     end
 
     # Test completing paths with an escaped trailing space
@@ -981,7 +976,7 @@ end
 let s = ""
     c, r = test_complete_context(s)
     @test "bar" in c
-    @test r ==ᵣ 1:0
+    @test r === UnitRange{Int64}(1:0)
     @test s[r] == ""
 end
 
diff --git a/test/sorting.jl b/test/sorting.jl
index 44b12894635cd..ad5438514261e 100644
--- a/test/sorting.jl
+++ b/test/sorting.jl
@@ -77,12 +77,6 @@ end
     @test_throws ArgumentError partialsortperm!([1,2], [2,3,1], 1:2)
 end
 
-# Compare ranges by comparing their `first` and `last` elements and their `length`. This
-# returns `false` if empty ranges have different startpoints, which is relevant for
-# `searchsorted`
-==ᵣ(r::AbstractRange, s::AbstractRange) =
-    (first(r) == first(s)) & (length(r) == length(s)) & (last(r) == last(s))
-
 @testset "searchsorted" begin
     numTypes = [ Int8,  Int16,  Int32,  Int64,  Int128,
                 UInt8, UInt16, UInt32, UInt64, UInt128,
@@ -100,10 +94,10 @@ end
         @test searchsorted(R[1, 1, 2, 2, 3, 3], T(4)) === 7:6
         @test searchsorted(R[1, 1, 2, 2, 3, 3], 2.5) === 5:4
 
-        @test searchsorted(1:3, T(0)) ==ᵣ 1:0
+        @test searchsorted(1:3, T(0)) === 1:0
         @test searchsorted(1:3, T(1)) == 1:1
         @test searchsorted(1:3, T(2)) == 2:2
-        @test searchsorted(1:3, T(4)) ==ᵣ 4:3
+        @test searchsorted(1:3, T(4)) === 4:3
 
         @test searchsorted(R[1:10;], T(1), by=(x -> x >= 5)) == 1:4
         @test searchsorted(R[1:10;], T(10), by=(x -> x >= 5)) == 5:10