diff --git a/Project.toml b/Project.toml
index 440063f6..797a91ef 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "JuliaInterpreter"
 uuid = "aa1ae85d-cabe-5617-a682-6adf51b2e16a"
-version = "0.8.7"
+version = "0.8.8"
 
 [deps]
 CodeTracking = "da1fd8a2-8d9e-5ec2-8556-3022fb5608a2"
diff --git a/src/builtins.jl b/src/builtins.jl
index 7956b8b6..ff85eb8e 100644
--- a/src/builtins.jl
+++ b/src/builtins.jl
@@ -168,11 +168,11 @@ function maybe_evaluate_builtin(frame, call_expr, expand::Bool)
         return Some{Any}(applicable(getargs(args, frame)...))
     elseif f === fieldtype
         if nargs == 2
-            return Some{Any}(fieldtype(@lookup(frame, args[2]), @lookup(frame, args[3])))
+            return Some{Any}(fieldtype(@lookup(frame, args[2]), @lookup(frame, args[3]))::Type)
         elseif nargs == 3
-            return Some{Any}(fieldtype(@lookup(frame, args[2]), @lookup(frame, args[3]), @lookup(frame, args[4])))
+            return Some{Any}(fieldtype(@lookup(frame, args[2]), @lookup(frame, args[3]), @lookup(frame, args[4]))::Type)
         else
-            return Some{Any}(fieldtype(getargs(args, frame)...))
+            return Some{Any}(fieldtype(getargs(args, frame)...)::Type)
         end
     elseif f === getfield
         if nargs == 2
diff --git a/src/optimize.jl b/src/optimize.jl
index 2216abac..0890e6fe 100644
--- a/src/optimize.jl
+++ b/src/optimize.jl
@@ -25,7 +25,7 @@ function extract_inner_call!(stmt::Expr, idx, once::Bool=false)
     return nothing
 end
 
-function replace_ssa!(stmt, ssalookup)
+function replace_ssa!(@nospecialize(stmt), ssalookup)
     isa(stmt, Expr) || return nothing
     for (i, a) in enumerate(stmt.args)
         if isa(a, SSAValue)
@@ -59,7 +59,7 @@ function renumber_ssa!(stmts::Vector{Any}, ssalookup)
                 stmt.args[end] = jumplookup(ssalookup, stmt.args[end])
             end
         elseif is_GotoIfNot(stmt)
-            cond = stmt.cond
+            cond = (stmt::Core.GotoIfNot).cond
             if isa(cond, SSAValue)
                 cond = SSAValue(ssalookup[cond.id])
             end
@@ -245,7 +245,7 @@ function optimize!(code::CodeInfo, scope)
     return code, methodtables
 end
 
-function parametric_type_to_expr(t::Type)
+function parametric_type_to_expr(@nospecialize(t::Type))
     t isa Core.TypeofBottom && return t
     t isa UnionAll && (t = t.body)
     t = t::DataType
@@ -253,7 +253,7 @@ function parametric_type_to_expr(t::Type)
         return Expr(:(...), t.parameters[1])
     end
     if t.hasfreetypevars
-        params = map(t.parameters) do p
+        params = map(t.parameters) do @nospecialize(p)
             isa(p, TypeVar) ? p.name :
             isa(p, DataType) && p.hasfreetypevars ? parametric_type_to_expr(p) : p
         end
@@ -403,10 +403,18 @@ end
 
 function replace_coretypes_list!(list::AbstractVector; rev::Bool)
     function rep(@nospecialize(x), rev::Bool)
-        if isa(x, rev ? SSAValue : Core.SSAValue)
-            return rev ? Core.SSAValue(x.id) : SSAValue(x.id)
-        elseif isa(x, rev ? SlotNumber : Core.SlotNumber)
-            return rev ? Core.SlotNumber(x.id) : SlotNumber(x.id)
+        if rev
+            if isa(x, SSAValue)
+                return Core.SSAValue(x.id)
+            elseif isa(x, SlotNumber)
+                return Core.SlotNumber(x.id)
+            end
+            return x
+        end
+        if isa(x, Core.SSAValue)
+            return SSAValue(x.id)
+        elseif isa(x, Core.SlotNumber)
+            return SlotNumber(x.id)
         end
         return x
     end
diff --git a/src/precompile.jl b/src/precompile.jl
index 671abcc3..9beff6d9 100644
--- a/src/precompile.jl
+++ b/src/precompile.jl
@@ -17,6 +17,7 @@ function _precompile_()
     @assert precompile(Tuple{typeof(eval_rhs), Any, Frame, Expr})
     @assert precompile(Tuple{typeof(step_expr!), Any, Frame, Any, Bool})
     for f in (finish!, finish_and_return!, finish_stack!, next_call!, maybe_next_call!, next_line!)
+        @assert precompile(Tuple{typeof(f), Any, Frame})
         @assert precompile(Tuple{typeof(f), Any, Frame, Bool})
     end
     @assert precompile(Tuple{typeof(through_methoddef_or_done!), Any, Frame})
@@ -51,4 +52,5 @@ function _precompile_()
         @assert precompile(Tuple{typeof(append_any), Any})
         @assert precompile(Tuple{typeof(append_any), Any, Vararg{Any, 100}})
     end
+    @assert precompile(Tuple{typeof(whichtt), Any})
 end
diff --git a/src/utils.jl b/src/utils.jl
index 04a188f2..aa04f381 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -123,11 +123,15 @@ end
 
 function scopename(tn::TypeName)
     modpath = Base.fullname(tn.module)
-    return Expr(:., _scopename(modpath...), QuoteNode(tn.name))
+    if isa(modpath, Tuple{Symbol})
+        return Expr(:., modpath[1], QuoteNode(tn.name))
+    end
+    ex = Expr(:., modpath[end-1], QuoteNode(modpath[end]))
+    for i = length(modpath)-2:-1:1
+        ex = Expr(:., modpath[i], ex)
+    end
+    return Expr(:., ex, QuoteNode(tn.name))
 end
-_scopename(sym) = sym
-_scopename(parent, child) = Expr(:., parent, QuoteNode(child))
-_scopename(parent, child, rest...) = Expr(:., parent, _scopename(child, rest...))
 
 ## Predicates
 
@@ -146,9 +150,11 @@ end
 if isdefined(Core, :ReturnNode)
     is_ReturnNode(@nospecialize(node)) = isa(node, Core.ReturnNode)
     is_return(@nospecialize(node)) = is_ReturnNode(node)
+    get_return_node(@nospecialize(node)) = (node::Core.ReturnNode).val
 else
     is_ReturnNode(@nospecialize(node)) = false
     is_return(@nospecialize(node)) = isexpr(node, :return)
+    get_return_node(@nospecialize(node)) = node.args[1]
 end
 
 is_loc_meta(@nospecialize(expr), @nospecialize(kind)) = isexpr(expr, :meta) && length(expr.args) >= 1 && expr.args[1] === kind
diff --git a/test/core.jl b/test/core.jl
index a3292a55..a8905690 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -23,4 +23,11 @@ using Test
     if isdefined(Base.IRShow, :show_ir_stmt)   # only works on Julia 1.6 and higher
         @test any(str->occursin(":copyast", str) && occursin("println", str), lines)
     end
+
+    thunk = Meta.lower(Main, :(return 1+2))
+    stmt = thunk.args[1].code[end]   # the return
+    @test JuliaInterpreter.get_return_node(stmt) isa Core.SSAValue
+
+    @test string(JuliaInterpreter.parametric_type_to_expr(Base.Iterators.Stateful{String})) ∈
+        ("Base.Iterators.Stateful{String, VS}", "(Base.Iterators).Stateful{String, VS}")
 end