Fix specialization of Base.return_types

Author: emmt

NEWS.md

@@ -19,6 +19,8 @@ This page describes the most important changes in `TypeUtils`. The format is bas
 
 - Better rule for element type conversion of `AbstractUnitRange` instances.
 
+- Fix specialization of `Base.return_types` which shall return a vector of types.
+
 
 ## Version 1.7.1 (2025-05-19)
 

src/funcs.jl

@@ -66,8 +66,7 @@ AbstractTypeStableFunction{T}(f) where {T} = TypeStableFunction{T}(f)
 # Extend base methods.
 Base.parent(obj::TypeStableFunction) = getfield(obj, :callable)
 
-Base.return_types(::AbstractTypeStableFunction{T}; kwds...) where {T} = (T,)
-Base.return_types(::AbstractTypeStableFunction{T}, ::DataType; kwds...) where {T} = (T,)
+Base.return_types(::AbstractTypeStableFunction{T}, ::Any=Tuple) where {T} = [T]
 
 Base.promote_op(::AbstractTypeStableFunction{T}, ::DataType...) where {T} = T
 

test/runtests.jl

@@ -544,8 +544,8 @@ same_value_and_type(x::T, y::T) where {T} = (x === y) || (x == y)
         @test return_type(g) === BigFloat
         @test return_type(typeof(f)) === Float32
         @test return_type(typeof(g)) === BigFloat
-        @test Base.return_types(f) === (return_type(f),)
-        @test Base.return_types(g) === (return_type(g),)
+        @test Base.return_types(f) == [return_type(f)]
+        @test Base.return_types(g, Tuple) == [return_type(g)]
         @test Base.promote_op(f, Int8) === return_type(f)
         @test Base.promote_op(f, Int8, Int16) === return_type(f)
         @test Base.promote_op(g, Float32) === return_type(g)