Handle nested where statements

src/utils.jl

@@ -99,15 +99,25 @@ function is_func_expr(@nospecialize(ex), meth::Method)
         if !(isa(fname, Symbol) && is_gensym(fname)) && !isexpr(fname, :$)
             if fname === :Type && isexpr(ex.args[1], :where) && isexpr(callex.args[1], :(::)) && isexpr(callex.args[1].args[end], :curly)
                 Tsym = callex.args[1].args[end].args[2]
-                for wheretyp in ex.args[1].args[2:end]
-                    @assert isexpr(wheretyp, :(<:))
-                    if Tsym == wheretyp.args[1]
-                        fname = wheretyp.args[2]
-                        break
+                whereex = ex.args[1]
+                while true
+                    found = false
+                    for wheretyp in whereex.args[2:end]
+                        isexpr(wheretyp, :(<:)) || continue
+                        if Tsym == wheretyp.args[1]
+                            fname = wheretyp.args[2]
+                            found = true
+                            break
+                        end
                     end
+                    found && break
+                    whereex = whereex.args[1]
                 end
             end
             # match the function name
+            if isexpr(fname, :curly)
+                fname = fname.args[1]
+            end
             fname === strip_gensym(meth.name) || return false
         end
         exargs = callex.args[2:end]

test/runtests.jl

@@ -273,6 +273,12 @@ isdefined(Main, :Revise) ? Main.Revise.includet("script.jl") : include("script.j
     if !isdefined(Main, :Revise)
         @test definition(String, only(methods(wrongline))) === nothing
     end
+
+    # Nested `where`s
+    m = @which Parametric{2}(5)
+    src, line = definition(String, m)
+    @test occursin("::Type{P}", src)
+    @test line == 148
 end
 
 @testset "With Revise" begin

test/script.jl

@@ -142,3 +142,7 @@ end
 
 wrongline() = 1    # for use testing #124
 only(methods(wrongline)).line = 9999   # unclear how it happened in the wild, but this at least catches the problem
+
+# Nested `where`s
+struct Parametric{N} end
+(::Type{P})(x::Int) where P<:Parametric{N} where N = P()