From bd936843d1e7cf8cf79de96535bf8ed221bb3ca0 Mon Sep 17 00:00:00 2001
From: kimikage <kimikage.ceo@gmail.com>
Date: Tue, 13 Oct 2026 01:59:16 +0900
Subject: [PATCH] Fix `floattype()` for non-concrete types while preserving the
 depwarn

---
 src/FixedPointNumbers.jl |  5 ++---
 test/fixed.jl            |  1 +
 test/normed.jl           |  1 +
 test/traits.jl           | 16 +++++++++++++++-
 4 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/FixedPointNumbers.jl b/src/FixedPointNumbers.jl
index 7bafaca2..e58f26ee 100644
--- a/src/FixedPointNumbers.jl
+++ b/src/FixedPointNumbers.jl
@@ -196,9 +196,8 @@ floattype(::Type{T}) where {T <: Integer} = Float64
 floattype(::Type{T}) where {T <: LongInts} = BigFloat
 floattype(::Type{T}) where {I <: Integer, T <: Rational{I}} = typeof(zero(I)/oneunit(I))
 floattype(::Type{<:AbstractIrrational}) = Float64
-floattype(::Type{X}) where {T <: ShortInts, X <: FixedPoint{T}} = Float32
-floattype(::Type{X}) where {T <: Integer, X <: FixedPoint{T}} = Float64
-floattype(::Type{X}) where {T <: LongInts, X <: FixedPoint{T}} = BigFloat
+floattype(::Type{<:FixedPoint}) = BigFloat # fallback for `FixedPoint`
+floattype(::Type{<:FixedPoint{T}}) where {T <: Integer} = isconcretetype(T) ? floattype(T) : BigFloat
 
 # Non-Real types
 floattype(::Type{Complex{T}}) where T = Complex{floattype(T)}
diff --git a/test/fixed.jl b/test/fixed.jl
index d0909c3b..1b5fdd86 100644
--- a/test/fixed.jl
+++ b/test/fixed.jl
@@ -245,6 +245,7 @@ end
     @test float(0.75Q10f53)::BigFloat == big"0.75"
 
     test_floattype(Fixed)
+    # see test/traits.jl for floattype tests for non-concrete types
 end
 
 @testset "conversions from float" begin
diff --git a/test/normed.jl b/test/normed.jl
index 50b60093..28974e35 100644
--- a/test/normed.jl
+++ b/test/normed.jl
@@ -210,6 +210,7 @@ end
     @test float(1N11f53)::BigFloat == big"1.0"
 
     test_floattype(Normed)
+    # see test/traits.jl for floattype tests for non-concrete types
 end
 
 @testset "conversions from float" begin
diff --git a/test/traits.jl b/test/traits.jl
index c248b4c0..e832b352 100644
--- a/test/traits.jl
+++ b/test/traits.jl
@@ -2,8 +2,21 @@ using FixedPointNumbers, Test
 using FixedPointNumbers: bitwidth
 
 struct MyReal <: Real end
+struct MyInteger <: Integer end
 
-@testset "floattype" begin
+@testset "floattype for non-concrete/non-FixedPoint types" begin
+    @test floattype(FixedPoint) === BigFloat
+    @test floattype(Normed) === BigFloat
+    @test floattype(Fixed) === BigFloat
+    @test floattype(FixedPoint{Int8}) === Float32
+    @test floattype(Normed{UInt32}) === Float64
+    @test floattype(Fixed{Int64}) === BigFloat
+    @test floattype(FixedPoint{MyInteger}) === Float64
+    @test floattype(FixedPoint{Union{},1}) === BigFloat
+    @test floattype(Normed{Unsigned,2}) === BigFloat
+    @test floattype(Fixed{T,3} where {T<:Signed}) === BigFloat
+    # TODO: eliminate `@test_skipped` when depwarn is eliminated.
+    @test_skip(@test_throws MethodError floattype(Fixed{T,3} where T)) # T is not bounded
     for T in (UInt8, UInt16, UInt32, UInt64, UInt128, Bool,
               Int8, Int16, Int32, Int64, Int128)
         @test typemax(T) <= maxintfloat(floattype(T))
@@ -17,4 +30,5 @@ struct MyReal <: Real end
     @test floattype(typeof(π))                    === Float64
 
     @test_skip(@test_throws MethodError floattype(MyReal))   # TODO: eliminate `@test_skipped` when depwarn is eliminated. See #177.
+    @test floattype(MyInteger) === Float64
 end