handle method signatures represented as GlobalRef/QuoteNode (#66)

Julia allows following method definitions, but LoweredCodeUtils
(and thus Revise) can't handle them well, and it lead to the issue
<timholy/Revise.jl#643>:
```julia
function foogr end
macro deffoogr()
    gr = GlobalRef(__module__, :foogr) # will be lowered to `GlobalRef`
    quote
        $gr(args...) = length(args)
    end
end
@deffoogr
@show foogr(1,2,3) # => 3

function fooqn end
macro deffooqn()
    sig = :($(GlobalRef(__module__, :fooqn))(args...)) # will be lowered to `QuoteNode`
    return Expr(:function, sig, Expr(:block, __source__, :(length(args))))
end
@deffooqn
@show fooqn(1,2,3) # => 3
```

---

fixes timholy/Revise.jl#643

Author: aviatesk

src/signatures.jl

@@ -152,7 +152,10 @@ function identify_framemethod_calls(frame)
                 end
             end
         elseif ismethod1(stmt)
-            key = stmt.args[1]::Symbol
+            key = stmt.args[1]
+            key = normalize_defsig(key, frame)
+            key === missing && continue
+            key = key::Symbol
             mi = get(methodinfos, key, nothing)
             if mi === nothing
                 methodinfos[key] = MethodInfo(i)
@@ -161,6 +164,8 @@ function identify_framemethod_calls(frame)
             end
         elseif ismethod3(stmt)
             key = stmt.args[1]
+            key = normalize_defsig(key, frame)
+            key === missing && continue
             if key isa Symbol
                 mi = methodinfos[key]
                 mi.stop = i
@@ -208,6 +213,18 @@ function identify_framemethod_calls(frame)
     return methodinfos, selfcalls
 end
 
+# try to normalize `def` to `Symbol` representation
+function normalize_defsig(@nospecialize(def), frame::Frame)
+    if def isa QuoteNode
+        parentmodule(def.value) === moduleof(frame) || return false
+        def = nameof(def.value)
+    elseif def isa GlobalRef
+        def.mod === moduleof(frame) || return false
+        def = def.name
+    end
+    return def
+end
+
 function callchain(selfcalls)
     calledby = Dict{Symbol,Union{Symbol,Bool,Nothing}}()
     for sc in selfcalls
@@ -469,8 +486,11 @@ function methoddef!(@nospecialize(recurse), signatures, frame::Frame, @nospecial
     end
     ismethod1(stmt) || error("expected method opening, got ", stmt)
     name = stmt.args[1]
+    name = normalize_defsig(name, frame)
     if isa(name, Bool)
         error("not valid for anonymous methods")
+    elseif name === missing
+        error("given invalid definition: $stmt")
     end
     name = name::Symbol
     while true  # methods containing inner methods may need multiple trips through this loop

test/signatures.jl

@@ -432,3 +432,41 @@ bodymethtest5(x, y=Dict(1=>2)) = 5
         end
     end
 end
+
+# https://github.com/timholy/Revise.jl/issues/643
+module Revise643
+
+using LoweredCodeUtils, JuliaInterpreter, Test
+
+# make sure to not define `foogr` before macro expansion,
+# otherwise it will be resolved as `QuoteNode`
+macro deffoogr()
+    gr = GlobalRef(__module__, :foogr) # will be lowered to `GlobalRef`
+    quote
+        $gr(args...) = length(args) + 2
+    end
+end
+let
+    ex = quote
+        @deffoogr
+        @show foogr(1,2,3)
+    end
+    methranges = rename_framemethods!(Frame(@__MODULE__, ex))
+    @test haskey(methranges, :foogr)
+end
+
+function fooqn end
+macro deffooqn()
+    sig = :($(GlobalRef(__module__, :fooqn))(args...)) # will be lowered to `QuoteNode`
+    return Expr(:function, sig, Expr(:block, __source__, :(length(args))))
+end
+let
+    ex = quote
+        @deffooqn
+        @show fooqn(1,2,3)
+    end
+    methranges = rename_framemethods!(Frame(@__MODULE__, ex))
+    @test haskey(methranges, :fooqn)
+end
+
+end