Do not warn on failed return type guessing (#409)

* Do not throw warnings

* Bump patch

* Remove redundant test case

Project.toml

@@ -1,7 +1,7 @@
 name = "Mooncake"
 uuid = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 authors = ["Will Tebbutt, Hong Ge, and contributors"]
-version = "0.4.54"
+version = "0.4.55"
 
 [deps]
 ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"

src/interpreter/s2s_reverse_mode_ad.jl

@@ -1735,14 +1735,12 @@ _rtype(T::Type{<:DerivedRule}) = Tuple{_rtype(fieldtype(T, :fwds_oc)),fieldtype(
         rule.rule = derived_rule
         result = derived_rule(args...)
     else
-        @warn "Unable to put rule in rule field. A `BadRuleTypeException` might be thrown."
         err = BadRuleTypeException(rule.mi, sig, typeof(derived_rule), Trule)
         result = try
             derived_rule(args...)
         catch
             throw(err)
         end
-        @warn "`BadRuleTypException was _not_ thrown. Expect an error at some point."
     end
     return result::_rtype(Trule)
 end

test/interpreter/s2s_reverse_mode_ad.jl

@@ -12,12 +12,6 @@ struct A
 end
 f(a, x) = dot(a.data, x)
 
-# Test cases designed to cause `LazyDerivedRule` to throw an error when attempting to
-# construct a rule for `bar`.
-foo(x) = x
-@noinline bar(x) = foo(x)
-baz(x) = bar(x)
-Mooncake.@is_primitive Mooncake.MinimalCtx Tuple{typeof(foo),Any}
 end
 
 @testset "s2s_reverse_mode_ad" begin
@@ -258,15 +252,6 @@ end
         rule = Mooncake.build_rrule(interp, sig; debug_mode)
         @test rule isa Mooncake.rule_type(interp, sig; debug_mode)
     end
-    @testset "LazyDerivedRule" begin
-        fargs = (S2SGlobals.baz, 5.0)
-        rule = build_rrule(fargs...)
-        msg = "Unable to put rule in rule field. A `BadRuleTypeException` might be thrown."
-        @test_logs(
-            (:warn, msg),
-            (@test_throws Mooncake.BadRuleTypeException rule(map(zero_fcodual, fargs)...)),
-        )
-    end
     @testset "MooncakeRuleCompilationError" begin
         @test_throws(Mooncake.MooncakeRuleCompilationError, Mooncake.build_rrule(sin))
     end