Test for identical type promotion

JuliaLang · Dec 8, 2024 · 30d1239 · 30d1239
1 parent 52e5024
commit 30d1239
Showing 1 changed file with 12 additions and 4 deletions.
diff --git a/test/core.jl b/test/core.jl
@@ -8390,10 +8390,18 @@ f_invalidate_me() = 2
 @test_throws ErrorException invoke(f_invoke_me, f_invoke_me_ci)
 @test_throws ErrorException f_call_me()
 
-@testset "error with conflicting promote_rules" begin
+@testset "promote_rule and promote_result overloads" begin
     struct PromoteA end
     struct PromoteB end
-    Base.promote_rule(::Type{PromoteA}, ::Type{PromoteB}) = PromoteA
-    Base.promote_rule(::Type{PromoteB}, ::Type{PromoteA}) = PromoteB
-    @test_throws ArgumentError promote_type(PromoteA, PromoteB)
+
+    @testset "error with conflicting promote_rules" begin
+        Base.promote_rule(::Type{PromoteA}, ::Type{PromoteB}) = PromoteA
+        Base.promote_rule(::Type{PromoteB}, ::Type{PromoteA}) = PromoteB
+        @test_throws ArgumentError promote_type(PromoteA, PromoteB)
+    end
+
+    @testset "promote_rule overload for identical types" begin
+        Base.promote_rule(::Type{PromoteA}, ::Type{PromoteA}) = PromoteB
+        @test promote_type(PromoteA, PromoteA) == PromoteB
+    end
 end