From 513743a38391c54c1186b999ac6f9051a99836f3 Mon Sep 17 00:00:00 2001
From: Tim Holy <tim.holy@gmail.com>
Date: Mon, 24 Aug 2020 08:10:25 -0500
Subject: [PATCH] Support MethodList

This is nice to collect MethodInstances from several methods.
---
 src/MethodAnalysis.jl |  4 ++--
 src/visit.jl          | 12 ++++++++++++
 test/runtests.jl      |  8 ++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/MethodAnalysis.jl b/src/MethodAnalysis.jl
index c06b94d..8ceff8a 100644
--- a/src/MethodAnalysis.jl
+++ b/src/MethodAnalysis.jl
@@ -116,10 +116,10 @@ end
     methodinstances(mod::Module)
     methodinstances(f)
 
-Collect all `MethodInstance`s, optionally restricting them to a particular module or function.
+Collect all `MethodInstance`s, optionally restricting them to a particular module, function, method, or methodlist.
 """
 function methodinstances(top=())
-    if isa(top, Module) || isa(top, Function) || isa(top, Type)
+    if isa(top, Module) || isa(top, Function) || isa(top, Type) || isa(top, Method) || isa(top, Base.MethodList)
         top = (top,)
     end
     mis = Core.MethodInstance[]
diff --git a/src/visit.jl b/src/visit.jl
index 9572e58..c258406 100644
--- a/src/visit.jl
+++ b/src/visit.jl
@@ -100,6 +100,18 @@ function _visit(@nospecialize(operation), @nospecialize(f::Callable), visited::I
     return nothing
 end
 
+function _visit(@nospecialize(operation), ml::Base.MethodList, visited::IdSet{Any}, print::Bool)
+    ml ∈ visited && return nothing
+    push!(visited, ml)
+    print && println("MethodList ", ml)
+    _visit(operation, ml.mt, visited, print)
+    for m in ml.ms
+        _visit(operation, m, visited, print)
+    end
+    return nothing
+end
+
+
 function _visit(@nospecialize(operation), mt::MethodTable, visited::IdSet{Any}, print::Bool)
     mt ∈ visited && return nothing
     push!(visited, mt)
diff --git a/test/runtests.jl b/test/runtests.jl
index 7c62599..ef7b96c 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -79,6 +79,14 @@ end
     @test mis isa Vector{Core.MethodInstance}
     @test mi ∈ mis
     @test length(mis) > 1
+
+    mi = methodinstance(convert, (Type{String}, String))
+    mis = methodinstances(methods(convert, (Type{String}, Any)))
+    @test length(mis) > 10  # in fact, there are many more
+    @test mi ∈ mis
+    mis = methodinstances(which(convert, (Type{String}, AbstractString)))
+    @test length(mis) > 2
+    @test mi ∉ mis   # that's covered by a different Method
 end
 
 @testset "Backedges" begin