From 5a0c15eb556f13871abce2bb7990feaac070dada Mon Sep 17 00:00:00 2001
From: Miles Cranmer <miles.cranmer@gmail.com>
Date: Wed, 17 Jan 2024 21:39:52 +0000
Subject: [PATCH 1/3] Create overloadable function for strings

---
 TypedSyntax/src/show.jl | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/TypedSyntax/src/show.jl b/TypedSyntax/src/show.jl
index f3bfbe05..9c6d9559 100644
--- a/TypedSyntax/src/show.jl
+++ b/TypedSyntax/src/show.jl
@@ -113,12 +113,14 @@ function type_annotation_mode(node, @nospecialize(T); type_annotations::Bool, hi
     return type_annotate, pre, pre2, post
 end
 
+type_string(T) = string(T)
+
 function show_annotation(io, @nospecialize(T), post, node, position; iswarn::Bool)
     diagnostics = get(io, :diagnostics, nothing)
     inlay_hints = get(io, :inlay_hints, nothing)
 
     print(io, post)
-    T_str = string(T)
+    T_str = type_string(T)
     if iswarn && is_type_unstable(T)
         color = is_small_union_or_tunion(T) ? :yellow : :red
         printstyled(io, "::", T_str; color)

From eaa8ae8444547c2077df49fb8bdb259536dcf157 Mon Sep 17 00:00:00 2001
From: Miles Cranmer <miles.cranmer@gmail.com>
Date: Wed, 17 Jan 2024 21:43:35 +0000
Subject: [PATCH 2/3] Document `type_string` and make available in `Cthulhu`

---
 TypedSyntax/src/show.jl | 7 +++++++
 src/Cthulhu.jl          | 1 +
 2 files changed, 8 insertions(+)

diff --git a/TypedSyntax/src/show.jl b/TypedSyntax/src/show.jl
index 9c6d9559..1709f248 100644
--- a/TypedSyntax/src/show.jl
+++ b/TypedSyntax/src/show.jl
@@ -113,6 +113,13 @@ function type_annotation_mode(node, @nospecialize(T); type_annotations::Bool, hi
     return type_annotate, pre, pre2, post
 end
 
+"""
+    type_string(type)
+
+Overload this function to implement custom annotations for types. For example,
+`type_string(::Type{Float32}) = "F32"` would result in `F32` being used to annotate
+any instance of a `Float32`.
+"""
 type_string(T) = string(T)
 
 function show_annotation(io, @nospecialize(T), post, node, position; iswarn::Bool)
diff --git a/src/Cthulhu.jl b/src/Cthulhu.jl
index 46b98bdc..fa1855c0 100644
--- a/src/Cthulhu.jl
+++ b/src/Cthulhu.jl
@@ -9,6 +9,7 @@ using REPL: REPL, AbstractTerminal
 using JuliaSyntax
 using JuliaSyntax: SyntaxNode, AbstractSyntaxNode, child, children
 using TypedSyntax
+using TypedSyntax: type_string
 using WidthLimitedIO
 
 using Core: MethodInstance, MethodMatch

From 2629d7b6f1d485170b6bb63ac7b35582e18d0cab Mon Sep 17 00:00:00 2001
From: MilesCranmer <miles.cranmer@gmail.com>
Date: Thu, 18 Jan 2024 05:04:06 +0000
Subject: [PATCH 3/3] Recurse in `type_string`

---
 TypedSyntax/src/show.jl | 21 ++++++++++++++++++++-
 test/test_codeview.jl   | 27 +++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/TypedSyntax/src/show.jl b/TypedSyntax/src/show.jl
index 1709f248..8eec4dad 100644
--- a/TypedSyntax/src/show.jl
+++ b/TypedSyntax/src/show.jl
@@ -120,7 +120,26 @@ Overload this function to implement custom annotations for types. For example,
 `type_string(::Type{Float32}) = "F32"` would result in `F32` being used to annotate
 any instance of a `Float32`.
 """
-type_string(T) = string(T)
+function type_string(T)
+    if T isa DataType
+        if isempty(T.parameters)
+            return string(T)
+        else
+            wrapper = Base.typename(T).wrapper
+            return string(wrapper, '{', join(map(type_string, T.parameters), ','), '}')
+        end
+    elseif T isa Union
+        params = union_to_tuple(T)
+        return string("Union{" * join(map(type_string, params), ",") * "}")
+    elseif T isa UnionAll
+        return string(type_string(T.body), " where ", string(T.var))
+    end
+    return string(T)
+end
+union_to_tuple(T) = (T,)
+function union_to_tuple(U::Union)
+    return (union_to_tuple(U.a)..., union_to_tuple(U.b)...)
+end
 
 function show_annotation(io, @nospecialize(T), post, node, position; iswarn::Bool)
     diagnostics = get(io, :diagnostics, nothing)
diff --git a/test/test_codeview.jl b/test/test_codeview.jl
index 8e531011..48159251 100644
--- a/test/test_codeview.jl
+++ b/test/test_codeview.jl
@@ -1,6 +1,7 @@
 module test_codeview
 
 using Cthulhu, Test, Revise
+import Cthulhu: type_string
 
 include("setup.jl")
 
@@ -113,4 +114,30 @@ end
     end
 end
 
+@testset "type aliases" begin
+    let
+        @gensym MyType
+        (; src, infos, mi, rt, exct, effects, slottypes) = @eval Module() begin
+            import Cthulhu: type_string
+            struct $MyType{T}
+                a::T
+            end
+            type_string(::Type{$MyType{T}}) where {T} = "Abracadabra{" * type_string(T) * ",5}"
+            $cthulhu_info() do
+                x = Union{$MyType{Float64},Missing}[]
+                return x
+            end
+        end
+        function prints(; kwargs...)
+            io = IOBuffer()
+            Cthulhu.cthulhu_typed(io, :none, src, rt, exct, effects, mi; kwargs...)
+            return String(take!(io))
+        end
+        let
+            s = prints()
+            @test occursin("Abracadabra{Float64,5}", s)
+        end
+    end
+end
+
 end # module test_codeview