Less method invalidations for OffsetInteger

src/offsetintegers.jl

@@ -67,14 +67,18 @@ for op in (:(+), :(-), :(*), :(/), :div)
     end
 end
 
-for op in (:(==), :(>=), :(<=), :(<), :(>), :sub_with_overflow)
+# No mixed OffsetInteger/Integer methods for the comparison operators: they
+# go through Base's promotion machinery (promote_rule + convert above) with
+# identical semantics, just like mixed +/-/* already do. Defining e.g.
+# `==(::Integer, ::OffsetInteger)` invalidates compiled comparison code in
+# unrelated packages whenever GeometryBasics loads (~1.8k method instances,
+# measured via SnoopCompile in a Makie session).
+for op in (:(==), :(>=), :(<=), :(<), :(>))
     @eval begin
         function Base.$op(x::OffsetInteger{O}, y::OffsetInteger{O}) where {O}
             return $op(x.i, y.i)
         end
         Base.$op(x::OffsetInteger, y::OffsetInteger) = $op(value(x), value(y))
-        Base.$op(x::OffsetInteger, y::Integer) = $op(value(x), y)
-        Base.$op(x::Integer, y::OffsetInteger) = $op(x, value(y))
     end
 end
 

test/runtests.jl

@@ -338,6 +338,45 @@ end
             @test <(x, x1)
         end
     end
+
+    # With a nonzero offset `raw != value`, so this exercises the arithmetic
+    # and the same-offset comparison method `op(x.i, y.i)` for an offset != 0.
+    let O = 3
+        a = OffsetInteger{O}(2)
+        b = OffsetInteger{O}(4)
+        @test GeometryBasics.value(a) == 2
+        @test GeometryBasics.raw(a) == 2 + O
+        @test Base.to_index(a) == 2
+        @test -(a)   == OffsetInteger{O}(-2)
+        @test abs(OffsetInteger{O}(-2)) == OffsetInteger{O}(2)
+        @test +(a, b)  == OffsetInteger{O}(6)
+        @test -(b, a)  == OffsetInteger{O}(2)
+        @test *(a, b)  == OffsetInteger{O}(8)
+        @test div(b, a) == OffsetInteger{O}(2)
+        @test a == OffsetInteger{O}(2)
+        @test a != b
+        @test a < b
+        @test a <= b
+        @test b > a
+        @test b >= a
+    end
+
+    # Comparing OffsetIntegers with *different* offsets goes through the
+    # value-based fallback method `op(value(x), value(y))`.
+    let
+        a = OffsetInteger{0}(5)  # value 5
+        b = OffsetInteger{3}(5)  # value 5
+        c = OffsetInteger{3}(7)  # value 7
+        @test a == b
+        @test a <= b
+        @test a >= b
+        @test !(a < b)
+        @test a < c
+        @test a <= c
+        @test c > a
+        @test c >= a
+        @test a != c
+    end
 end
 
 @testset "Tests from GeometryTypes" begin