From f15bf710565a261998be1d5f320372e76ab9d4bf Mon Sep 17 00:00:00 2001
From: Yue Zhengyuan <yuezy1997@icloud.com>
Date: Sat, 24 Oct 2026 10:55:07 +0800
Subject: [PATCH] Fix tensor map subtype bounds and add regression coverage

---
 .gitignore                    |  1 +
 src/tensors/adjoint.jl        |  4 ++--
 src/tensors/braidingtensor.jl |  4 ++--
 src/tensors/diagonal.jl       |  2 +-
 src/tensors/tensor.jl         |  4 ++--
 test/tensors/subtyping.jl     | 12 ++++++++++++
 6 files changed, 20 insertions(+), 7 deletions(-)
 create mode 100644 test/tensors/subtyping.jl

diff --git a/.gitignore b/.gitignore
index 22b0fc821..3e6da32ea 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,7 @@
 __pycache__
 .ipynb*
 *Manifest.toml
+*LocalPreferences.toml
 .vscode
 experimental
 refs
diff --git a/src/tensors/adjoint.jl b/src/tensors/adjoint.jl
index 2297643ce..39c785375 100644
--- a/src/tensors/adjoint.jl
+++ b/src/tensors/adjoint.jl
@@ -1,12 +1,12 @@
 # AdjointTensorMap: lazy adjoint
 #==========================================================#
 """
-    struct AdjointTensorMap{T, S, N₁, N₂, TT<:AbstractTensorMap} <: AbstractTensorMap{T, S, N₁, N₂}
+    struct AdjointTensorMap{T<:Number, S<:IndexSpace, N₁, N₂, TT<:AbstractTensorMap} <: AbstractTensorMap{T, S, N₁, N₂}
 
 Specific subtype of [`AbstractTensorMap`](@ref) that is a lazy wrapper for representing the
 adjoint of an instance of [`AbstractTensorMap`](@ref).
 """
-struct AdjointTensorMap{T, S, N₁, N₂, TT <: AbstractTensorMap{T, S, N₂, N₁}} <:
+struct AdjointTensorMap{T <: Number, S <: IndexSpace, N₁, N₂, TT <: AbstractTensorMap{T, S, N₂, N₁}} <:
     AbstractTensorMap{T, S, N₁, N₂}
     parent::TT
 end
diff --git a/src/tensors/braidingtensor.jl b/src/tensors/braidingtensor.jl
index 0635f7988..ea72f713b 100644
--- a/src/tensors/braidingtensor.jl
+++ b/src/tensors/braidingtensor.jl
@@ -2,7 +2,7 @@
 # special (2,2) tensor that implements a standard braiding operation
 #====================================================================#
 """
-    struct BraidingTensor{T, S <: IndexSpace, A <: DenseVector{T}} <: AbstractTensorMap{T, S, 2, 2}
+    struct BraidingTensor{T <: Number, S <: IndexSpace, A <: DenseVector{T}} <: AbstractTensorMap{T, S, 2, 2}
     BraidingTensor(V1::S, V2::S, adjoint::Bool=false) where {S<:IndexSpace}
     BraidingTensor{T, S, A}(V1::S, V2::S, adjoint::Bool=false) where {T, S, A}
 
@@ -14,7 +14,7 @@ It holds that `domain(BraidingTensor(V1, V2)) == V1 ⊗ V2` and
 controls the array type of the braiding tensor used when indexing
 and multiplying with other tensors.
 """
-struct BraidingTensor{T, S, A <: DenseVector{T}} <: AbstractTensorMap{T, S, 2, 2}
+struct BraidingTensor{T <: Number, S <: IndexSpace, A <: DenseVector{T}} <: AbstractTensorMap{T, S, 2, 2}
     V1::S
     V2::S
     adjoint::Bool
diff --git a/src/tensors/diagonal.jl b/src/tensors/diagonal.jl
index 630f1866a..8a59fa96b 100644
--- a/src/tensors/diagonal.jl
+++ b/src/tensors/diagonal.jl
@@ -1,6 +1,6 @@
 # DiagonalTensorMap
 #==========================================================#
-struct DiagonalTensorMap{T, S <: IndexSpace, A <: DenseVector{T}} <: AbstractTensorMap{T, S, 1, 1}
+struct DiagonalTensorMap{T <: Number, S <: IndexSpace, A <: DenseVector{T}} <: AbstractTensorMap{T, S, 1, 1}
     data::A
     domain::S # equals codomain
 
diff --git a/src/tensors/tensor.jl b/src/tensors/tensor.jl
index 1aeb0070c..3888959d3 100644
--- a/src/tensors/tensor.jl
+++ b/src/tensors/tensor.jl
@@ -2,12 +2,12 @@
 # general tensor implementation with arbitrary symmetries
 #==========================================================#
 """
-    struct TensorMap{T, S<:IndexSpace, N₁, N₂, A<:DenseVector{T}} <: AbstractTensorMap{T, S, N₁, N₂}
+    struct TensorMap{T<:Number, S<:IndexSpace, N₁, N₂, A<:DenseVector{T}} <: AbstractTensorMap{T, S, N₁, N₂}
 
 Specific subtype of [`AbstractTensorMap`](@ref) for representing tensor maps (morphisms in
 a tensor category), where the data is stored in a dense vector.
 """
-struct TensorMap{T, S <: IndexSpace, N₁, N₂, A <: DenseVector{T}} <: AbstractTensorMap{T, S, N₁, N₂}
+struct TensorMap{T <: Number, S <: IndexSpace, N₁, N₂, A <: DenseVector{T}} <: AbstractTensorMap{T, S, N₁, N₂}
     data::A
     space::TensorMapSpace{S, N₁, N₂}
 
diff --git a/test/tensors/subtyping.jl b/test/tensors/subtyping.jl
new file mode 100644
index 000000000..6d6ae0252
--- /dev/null
+++ b/test/tensors/subtyping.jl
@@ -0,0 +1,12 @@
+using Test
+using TensorKit
+using TensorKit: AdjointTensorMap
+
+@testset "Tensor map subtyping" begin
+    for TT in (TensorMap, DiagonalTensorMap, AdjointTensorMap, BraidingTensor)
+        @test TT <: AbstractTensorMap
+        for T in (Float64, ComplexF64)
+            @test TT{T} <: AbstractTensorMap{T}
+        end
+    end
+end