From 1239dd4809cb92f10b0a22adab058c28af255598 Mon Sep 17 00:00:00 2001
From: Lilith Hafner <Lilith.Hafner@gmail.com>
Date: Fri, 9 Jun 2023 08:41:40 -0500
Subject: [PATCH 1/2] make (1:3:4)[6148914691236517207] throw (and test)

---
 base/range.jl  | 16 ++++++++++------
 test/ranges.jl |  8 ++++++++
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/base/range.jl b/base/range.jl
index f0bcc0dd20ae8..e82aa341db108 100644
--- a/base/range.jl
+++ b/base/range.jl
@@ -934,12 +934,16 @@ end
 function getindex(v::AbstractRange{T}, i::Integer) where T
     @inline
     i isa Bool && throw(ArgumentError("invalid index: $i of type Bool"))
-    ret = convert(T, first(v) + (i - oneunit(i))*step_hp(v))
-    ok = ifelse(step(v) > zero(step(v)),
-                (ret <= last(v)) & (ret >= first(v)),
-                (ret <= first(v)) & (ret >= last(v)))
-    @boundscheck ((i > 0) & ok) || throw_boundserror(v, i)
-    ret
+    @boundscheck checkbounds(v, i)
+    convert(T, first(v) + (i - oneunit(i))*step_hp(v))
+end
+
+let BitInteger64 = Union{Int8,Int16,Int32,Int64,UInt8,UInt16,UInt32,UInt64} # for bootstrapping
+    function checkbounds(::Type{Bool}, v::StepRange{<:BitInteger64, <:BitInteger64}, i::BitInteger64)
+        @inline
+        res = widemul(step(v), i-oneunit(i)) + first(v)
+        (0 < i) & ifelse(0 < step(v), res <= last(v), res >= last(v))
+    end
 end
 
 function getindex(r::Union{StepRangeLen,LinRange}, i::Integer)
diff --git a/test/ranges.jl b/test/ranges.jl
index 98233267d03a9..7b133d1bdf388 100644
--- a/test/ranges.jl
+++ b/test/ranges.jl
@@ -2487,3 +2487,11 @@ function check_ranges(rx, ry)
 end
 @test Core.Compiler.is_foldable(Base.infer_effects(check_ranges, (UnitRange{Int},UnitRange{Int})))
 # TODO JET.@test_opt check_ranges(1:2, 3:4)
+
+@testset "checkbounds overflow (#26623)" begin
+    # the reported issue:
+    @test (1:3:4)[typemax(Int)÷3*2+3]
+
+    # a case that using mul_with_overflow & add_with_overflow might get wrong:
+    @test (-10:2:typemax(Int))[typemax(Int)÷2+2] == typemax(Int)-9
+true

From 428ed0fd21313f2258faeb3ee264b3bffdec0ffb Mon Sep 17 00:00:00 2001
From: Lilith Hafner <Lilith.Hafner@gmail.com>
Date: Sat, 10 Jun 2023 07:54:34 -0500
Subject: [PATCH 2/2] fix typos in tests

---
 test/ranges.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/ranges.jl b/test/ranges.jl
index 7b133d1bdf388..2e91e1ddbe078 100644
--- a/test/ranges.jl
+++ b/test/ranges.jl
@@ -2490,8 +2490,8 @@ end
 
 @testset "checkbounds overflow (#26623)" begin
     # the reported issue:
-    @test (1:3:4)[typemax(Int)÷3*2+3]
+    @test_throws BoundsError (1:3:4)[typemax(Int)÷3*2+3]
 
     # a case that using mul_with_overflow & add_with_overflow might get wrong:
     @test (-10:2:typemax(Int))[typemax(Int)÷2+2] == typemax(Int)-9
-true
+end