From 268c2758a372f2ceec74bd6ada0c4666cf8a4c5c Mon Sep 17 00:00:00 2001
From: Jakob Peters <jakobj.peters@gmail.com>
Date: Mon, 16 Dec 2024 06:59:52 -0800
Subject: [PATCH] Visit callable objects

---
 src/visit.jl     | 15 ++++++++++++++-
 test/runtests.jl | 14 ++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/visit.jl b/src/visit.jl
index 59ff1f3..ddb29f1 100644
--- a/src/visit.jl
+++ b/src/visit.jl
@@ -223,7 +223,20 @@ if isdefined(Core, :CodeInstance)
     end
 end
 
-_visit(@nospecialize(operation), @nospecialize(x), visited::IdSet{Any}, print::Bool) = nothing
+function _visit(@nospecialize(operation), @nospecialize(x), visited::IdSet{Any}, print::Bool)
+    x ∈ visited && return nothing
+    x === Vararg && return nothing
+    push!(visited, x)
+    print && (show(x); println())
+    if operation(x)
+        ml = methods(x)
+        _visit(operation, ml.mt, visited, print)
+        for m in ml.ms
+            _visit(operation, m, visited, print)
+        end
+    end
+    return nothing
+end
 
 """
     visit_backedges(operation, obj)
diff --git a/test/runtests.jl b/test/runtests.jl
index 1a62c9d..dcc5eab 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -56,6 +56,11 @@ module Two
     One.f(x::Int) = x + 2
 end
 
+module CallableObjects
+    struct Foo end
+    (::Foo)() = 1
+    Foo()()
+end
 
 @testset "visit" begin
     # Do we pick up kwfuncs?
@@ -121,6 +126,15 @@ end
         isa(m, Method) && @test Base.unwrap_unionall(m.sig).parameters[1].parameters[1] === IndexStyle
         return m === IndexStyle
     end
+
+    # See issue #50
+    foo = CallableObjects.Foo()
+    empty!(mis)
+    visit(foo) do x
+        isa(x, Core.MethodInstance) && push!(mis, x)
+        true
+    end
+    @test only(mis) == only(methods(foo)).specializations
 end
 
 @testset "visit_withmodule" begin