diff --git a/src/CodeTracking.jl b/src/CodeTracking.jl
index f59ff59..a21fc46 100644
--- a/src/CodeTracking.jl
+++ b/src/CodeTracking.jl
@@ -30,6 +30,13 @@ is the first line of the method's body.
 """
 function whereis(method::Method)
     lin = get(method_info, method.sig, nothing)
+    if lin === nothing
+        f = method_lookup_callback[]
+        if f !== nothing
+            Base.invokelatest(f, method)
+        end
+        lin = get(method_info, method.sig, nothing)
+    end
     if lin === nothing
         file, line = String(method.file), method.line
     else
@@ -194,4 +201,8 @@ were loaded to define the package that defined `mod`.
 """
 pkgfiles(mod::Module) = pkgfiles(PkgId(mod))
 
+if ccall(:jl_generating_output, Cint, ()) == 1
+    precompile(Tuple{typeof(setindex!), Dict{PkgId,PkgFiles}, PkgFiles, PkgId})
+end
+
 end # module