diff --git a/Cargo.lock b/Cargo.lock
index 31d3a6fbce..1712f4e1bf 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -323,6 +323,7 @@ dependencies = [
  "itertools",
  "log",
  "serde",
+ "strum",
 ]
 
 [[package]]
@@ -1026,6 +1027,12 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ffc183a10b4478d04cbbbfc96d0873219d962dd5accaff2ffbd4ceb7df837f4"
+
 [[package]]
 name = "ryu"
 version = "1.0.15"
@@ -1177,6 +1184,28 @@ version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
 
+[[package]]
+name = "strum"
+version = "0.25.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "290d54ea6f91c969195bdbcd7442c8c2a2ba87da8bf60a7ee86a235d4bc1e125"
+dependencies = [
+ "strum_macros",
+]
+
+[[package]]
+name = "strum_macros"
+version = "0.25.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ad8d03b598d3d0fff69bf533ee3ef19b8eeb342729596df84bcc7e1f96ec4059"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.29"
diff --git a/crates/dfcheck/src/context.rs b/crates/dfcheck/src/context.rs
index 6c96cad365..c30b44256d 100644
--- a/crates/dfcheck/src/context.rs
+++ b/crates/dfcheck/src/context.rs
@@ -40,7 +40,7 @@ impl Context {
             .iter()
             .flat_map(|(id, (annots, _))| {
                 annots.iter().filter_map(move |annot| match annot {
-                    Annotation::Label(MarkerAnnotation { marker, refinement }) => {
+                    Annotation::Marker(MarkerAnnotation { marker, refinement }) => {
                         Some((*marker, (*id, refinement.clone())))
                     }
                     _ => None,
@@ -305,7 +305,7 @@ fn test_happens_before() -> Result<()> {
             desc.annotations
                 .get(&function.function)
                 .map_or(false, |(anns, _)| {
-                    anns.iter().filter_map(Annotation::as_label_ann).any(|ann| {
+                    anns.iter().filter_map(Annotation::as_marker).any(|ann| {
                         ann.marker == marker
                             && (ann
                                 .refinement
@@ -340,7 +340,7 @@ fn test_happens_before() -> Result<()> {
                 DataSource::Argument(arg) => desc.annotations[&ctrl_name]
                     .0
                     .iter()
-                    .filter_map(Annotation::as_label_ann)
+                    .filter_map(Annotation::as_marker)
                     .any(|ann| {
                         ann.marker == marker
                             && (ann.refinement.on_self()
@@ -353,7 +353,7 @@ fn test_happens_before() -> Result<()> {
                 DataSource::FunctionCall(cs) => desc.annotations[&cs.function]
                     .0
                     .iter()
-                    .filter_map(Annotation::as_label_ann)
+                    .filter_map(Annotation::as_marker)
                     .any(|ann| {
                         ann.marker == marker
                             && (ann.refinement.on_self() || ann.refinement.on_return())
diff --git a/crates/dfgraph/Cargo.toml b/crates/dfgraph/Cargo.toml
index e6589d3e76..8c55eba5be 100644
--- a/crates/dfgraph/Cargo.toml
+++ b/crates/dfgraph/Cargo.toml
@@ -15,3 +15,4 @@ log = "0.4"
 internment = { version = "0.7.1", features = ["serde"] }
 indexical = { workspace = true }
 itertools = "0.11.0"
+strum = { version = "0.25", features = ["derive"] }
\ No newline at end of file
diff --git a/crates/dfgraph/src/lib.rs b/crates/dfgraph/src/lib.rs
index e36be33e51..b6dba08da0 100644
--- a/crates/dfgraph/src/lib.rs
+++ b/crates/dfgraph/src/lib.rs
@@ -18,6 +18,8 @@ pub(crate) mod rustc {
     pub use middle::mir;
 }
 
+extern crate strum;
+
 pub mod global_location;
 #[cfg(feature = "rustc")]
 mod rustc_impls;
@@ -29,7 +31,6 @@ use global_location::GlobalLocation;
 use indexical::define_index_type;
 use internment::Intern;
 use itertools::Itertools;
-use log::warn;
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use std::{borrow::Cow, fmt, hash::Hash, iter};
 
@@ -43,31 +44,27 @@ pub type Function = Identifier;
 /// Types of annotations we support.
 ///
 /// Usually you'd expect one of those annotation types in any given situation.
-/// For convenience the match methods [`Self::as_label_ann`],
-/// [`Self::as_otype_ann`] and [`Self::as_exception_annotation`] are provided. These are particularly useful in conjunction with e.g. [`Iterator::filter_map`]
-#[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Deserialize, Serialize)]
+/// For convenience the match methods [`Self::as_marker`], [`Self::as_otype`]
+/// and [`Self::as_exception`] are provided. These are particularly useful in
+/// conjunction with e.g. [`Iterator::filter_map`]
+#[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Deserialize, Serialize, strum::EnumIs)]
 pub enum Annotation {
-    Label(MarkerAnnotation),
+    Marker(MarkerAnnotation),
     OType(Vec<TypeDescriptor>),
     Exception(ExceptionAnnotation),
 }
 
 impl Annotation {
-    /// If this is an [`Annotation::Label`], returns the underlying [`MarkerAnnotation`].
-    pub fn as_label_ann(&self) -> Option<&MarkerAnnotation> {
+    /// If this is an [`Annotation::Marker`], returns the underlying [`MarkerAnnotation`].
+    pub fn as_marker(&self) -> Option<&MarkerAnnotation> {
         match self {
-            Annotation::Label(l) => Some(l),
+            Annotation::Marker(l) => Some(l),
             _ => None,
         }
     }
 
-    /// Returns true if this is an [`Annotation::Label`].
-    pub fn is_label_ann(&self) -> bool {
-        matches!(self, Annotation::Label(_))
-    }
-
     /// If this is an [`Annotation::OType`], returns the underlying [`TypeDescriptor`].
-    pub fn as_otype_ann(&self) -> Option<&[TypeDescriptor]> {
+    pub fn as_otype(&self) -> Option<&[TypeDescriptor]> {
         match self {
             Annotation::OType(t) => Some(t),
             _ => None,
@@ -75,7 +72,7 @@ impl Annotation {
     }
 
     /// If this is an [`Annotation::Exception`], returns the underlying [`ExceptionAnnotation`].
-    pub fn as_exception_annotation(&self) -> Option<&ExceptionAnnotation> {
+    pub fn as_exception(&self) -> Option<&ExceptionAnnotation> {
         match self {
             Annotation::Exception(e) => Some(e),
             _ => None,
@@ -92,10 +89,10 @@ pub struct ExceptionAnnotation {
     pub verification_hash: Option<VerificationHash>,
 }
 
-/// A label annotation and its refinements.
+/// A marker annotation and its refinements.
 #[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Serialize, Deserialize)]
 pub struct MarkerAnnotation {
-    /// The (unchanged) name of the label as provided by the user
+    /// The (unchanged) name of the marker as provided by the user
     pub marker: Identifier,
     #[serde(flatten)]
     pub refinement: MarkerRefinement,
@@ -105,7 +102,7 @@ fn const_false() -> bool {
     false
 }
 
-/// Refinements in the label targeting. The default (no refinement provided) is
+/// Refinements in the marker targeting. The default (no refinement provided) is
 /// `on_argument == vec![]` and `on_return == false`, which is also what is
 /// returned from [`Self::empty`].
 #[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Deserialize, Serialize)]
@@ -116,6 +113,8 @@ pub struct MarkerRefinement {
     on_return: bool,
 }
 
+/// Disaggregated version of [`MarkerRefinement`]. Can be added to an existing
+/// refinement [`MarkerRefinement::merge_kind`].
 #[derive(Clone, Deserialize, Serialize)]
 pub enum MarkerRefinementKind {
     Argument(#[serde(with = "crate::tiny_bitset::pretty")] TinyBitSet),
@@ -158,10 +157,12 @@ impl MarkerRefinement {
         }
     }
 
+    /// Get the refinements on arguments
     pub fn on_argument(&self) -> TinyBitSet {
         self.on_argument
     }
 
+    /// Is this refinement targeting the return value?
     pub fn on_return(&self) -> bool {
         self.on_return
     }
@@ -173,7 +174,7 @@ impl MarkerRefinement {
     }
 }
 
-#[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Serialize, Deserialize)]
+#[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Serialize, Deserialize, strum::EnumIs)]
 pub enum ObjectType {
     Function(usize),
     Type,
@@ -181,33 +182,13 @@ pub enum ObjectType {
 }
 
 impl ObjectType {
-    pub fn is_function(&self) -> Option<usize> {
+    /// If this is [`Self::Function`], then return the payload.
+    pub fn as_function(&self) -> Option<usize> {
         match self {
             ObjectType::Function(f) => Some(*f),
             _ => None,
         }
     }
-    pub fn merge(&mut self, other: &Self) {
-        if self != other {
-            warn!(
-                "Merging two different object types {:?} and {:?}!",
-                self, other
-            );
-            match (self, other) {
-                (ObjectType::Function(ref mut i), ObjectType::Function(j)) => {
-                    if j > i {
-                        *i = *j
-                    }
-                }
-                (slf, other) => {
-                    panic!("Cannot merge two different object types {slf:?} and {other:?}")
-                }
-            }
-        }
-    }
-    pub fn is_type(&self) -> bool {
-        matches!(self, ObjectType::Type)
-    }
 }
 
 pub type AnnotationMap = HashMap<Identifier, (Vec<Annotation>, ObjectType)>;
@@ -305,7 +286,7 @@ impl ProgramDescription {
             .chain(
                 self.annotations
                     .iter()
-                    .filter(|f| f.1 .1.is_function().is_some())
+                    .filter(|f| f.1 .1.as_function().is_some())
                     .map(|f| f.0),
             )
             .collect()
diff --git a/crates/dfpp/src/ana/mod.rs b/crates/dfpp/src/ana/mod.rs
index 97c0d4b526..7a8cd5d5ae 100644
--- a/crates/dfpp/src/ana/mod.rs
+++ b/crates/dfpp/src/ana/mod.rs
@@ -290,7 +290,7 @@ impl<'tcx> CollectingVisitor<'tcx> {
                         .chain(self.marker_ctx.external_annotations().iter().map(|(did, anns)| {
                             (
                                 *did,
-                                anns.iter().cloned().map(Annotation::Label).collect(),
+                                anns.iter().cloned().map(Annotation::Marker).collect(),
                             )
                         }))
                         .map(|(did, anns)| {
diff --git a/crates/dfpp/src/frg.rs b/crates/dfpp/src/frg.rs
index 73a4becb9e..af3b91ed36 100644
--- a/crates/dfpp/src/frg.rs
+++ b/crates/dfpp/src/frg.rs
@@ -590,7 +590,7 @@ impl ProgramDescriptionExt for ProgramDescription {
         self.annotations
             .values()
             .flat_map(|v| v.0.iter())
-            .filter_map(Annotation::as_label_ann)
+            .filter_map(Annotation::as_marker)
             .map(|a| a.marker)
             .chain(std::iter::once(Identifier::new_intern(
                 name::EXCEPTIONS_LABEL,
@@ -678,51 +678,52 @@ impl ProgramDescriptionExt for ProgramDescription {
                 // Part of why we choose this behavior is because there is no
                 // call-site-independent representation for arguments, so the
                 // label has to be attached to the call site argument.
-                anns.iter()
-                    .filter_map(Annotation::as_label_ann)
-                    .map(move |a| {
-                        (
-                            if a.refinement.on_return() {
-                                Some(self.all_sources_with_ctrl().into_iter().filter(|(_, s)| {
-                                    s.as_function_call().map_or(false, |c| &c.function == id)
-                                }))
-                            } else {
-                                None
-                            }
-                            .into_iter()
-                            .flatten()
-                            .map(|(ctrl, ds)| data_source_as_forge(ds, alloc, ctrl))
-                            .chain(
-                                self.all_sinks()
-                                    .into_iter()
-                                    .filter(|s| {
-                                        matches!(
-                                            s,
-                                            DataSink::Argument{function, arg_slot} if
-                                            &function.function == id
-                                                && a.refinement
-                                                    .on_argument()
-                                                    .is_set(*arg_slot as u32)
-                                        )
-                                    })
-                                    .map(|s| s.build_forge(alloc)),
-                            )
-                            .chain([id.build_forge(alloc)])
-                            .chain(a.refinement.on_argument().into_iter_set_in_domain().map(
-                                |slot| {
+                anns.iter().filter_map(Annotation::as_marker).map(move |a| {
+                    (
+                        if a.refinement.on_return() {
+                            Some(self.all_sources_with_ctrl().into_iter().filter(|(_, s)| {
+                                s.as_function_call().map_or(false, |c| &c.function == id)
+                            }))
+                        } else {
+                            None
+                        }
+                        .into_iter()
+                        .flatten()
+                        .map(|(ctrl, ds)| data_source_as_forge(ds, alloc, ctrl))
+                        .chain(
+                            self.all_sinks()
+                                .into_iter()
+                                .filter(|s| {
+                                    matches!(
+                                        s,
+                                        DataSink::Argument{function, arg_slot} if
+                                        &function.function == id
+                                            && a.refinement
+                                                .on_argument()
+                                                .is_set(*arg_slot as u32)
+                                    )
+                                })
+                                .map(|s| s.build_forge(alloc)),
+                        )
+                        .chain([id.build_forge(alloc)])
+                        .chain(
+                            a.refinement
+                                .on_argument()
+                                .into_iter_set_in_domain()
+                                .map(|slot| {
                                     FormalParameter {
                                         function: *id,
                                         position: slot as u16,
                                     }
                                     .build_forge(alloc)
-                                },
-                            ))
-                            // This is necessary because otherwise captured variables escape
-                            .collect::<Vec<_>>()
-                            .into_iter(),
-                            std::iter::once(a.marker.build_forge(alloc)),
+                                }),
                         )
-                    })
+                        // This is necessary because otherwise captured variables escape
+                        .collect::<Vec<_>>()
+                        .into_iter(),
+                        std::iter::once(a.marker.build_forge(alloc)),
+                    )
+                })
             }))
             .append(" +")
             .append(alloc.hardline())
@@ -730,7 +731,7 @@ impl ProgramDescriptionExt for ProgramDescription {
                 alloc.forge_relation(self.annotations.iter().map(|(id, (anns, _))| {
                     (
                         anns.iter()
-                            .filter_map(Annotation::as_exception_annotation)
+                            .filter_map(Annotation::as_exception)
                             .next()
                             .map(|_| id.build_forge(alloc))
                             .into_iter(),
@@ -783,7 +784,7 @@ impl ProgramDescriptionExt for ProgramDescription {
             (
                 std::iter::once(o.build_forge(alloc)),
                 anns.iter()
-                    .filter_map(Annotation::as_otype_ann)
+                    .filter_map(Annotation::as_otype)
                     .flat_map(|v| v.iter())
                     .map(|t| t.build_forge(alloc)),
             )
@@ -1144,7 +1145,7 @@ impl ProgramDescriptionExt for ProgramDescription {
                                         alloc.forge_relation_with_arity(3,
                                             self.annotations.iter()
                                                 .flat_map(|(ident, (anns, _))|
-                                                    anns.iter().filter_map(Annotation::as_label_ann)
+                                                    anns.iter().filter_map(Annotation::as_marker)
                                                         .flat_map(|label|
                                                             label.refinement.on_argument().into_iter_set_in_domain().map(|i|
                                                                 (
diff --git a/crates/dfpp/src/marker_db.rs b/crates/dfpp/src/marker_db.rs
index bc6412751d..8753ef0ebd 100644
--- a/crates/dfpp/src/marker_db.rs
+++ b/crates/dfpp/src/marker_db.rs
@@ -81,7 +81,7 @@ impl<'tcx> MarkerCtx<'tcx> {
             .as_local()
             .map(|ldid| self.local_annotations(ldid))
             .into_iter()
-            .flat_map(|anns| anns.iter().flat_map(Annotation::as_label_ann))
+            .flat_map(|anns| anns.iter().flat_map(Annotation::as_marker))
             .chain(self.external_markers(def_id).iter())
     }
 
@@ -94,7 +94,7 @@ impl<'tcx> MarkerCtx<'tcx> {
     pub fn is_locally_marked(&self, def_id: LocalDefId) -> bool {
         self.local_annotations(def_id)
             .iter()
-            .any(Annotation::is_label_ann)
+            .any(Annotation::is_marker)
     }
 
     /// Are there any markers (local or external) on this item?
@@ -192,11 +192,11 @@ impl<'tcx> MarkerCtx<'tcx> {
             .iter()
             .filter_map(|a| {
                 a.match_extract(&consts::MARKER_MARKER, |i| {
-                    Annotation::Label(crate::ann_parse::ann_match_fn(i))
+                    Annotation::Marker(crate::ann_parse::ann_match_fn(i))
                 }).or_else(||
                     a.match_extract(&consts::LABEL_MARKER, |i| {
                         warn!("The `dfpp::label` annotation is deprecated, use `dfpp::marker` instead");
-                        Annotation::Label(crate::ann_parse::ann_match_fn(i))
+                        Annotation::Marker(crate::ann_parse::ann_match_fn(i))
                     })
                 )
                 .or_else(|| {
diff --git a/crates/dfpp/src/test_utils.rs b/crates/dfpp/src/test_utils.rs
index 4dde7c8126..92f83f36b5 100644
--- a/crates/dfpp/src/test_utils.rs
+++ b/crates/dfpp/src/test_utils.rs
@@ -571,7 +571,7 @@ pub trait HasGraph<'g>: Sized + Copy {
         let marker = Identifier::new_intern(marker);
         self.graph().0.annotations.values().any(|v| {
             v.0.iter()
-                .filter_map(|a| a.as_label_ann())
+                .filter_map(|a| a.as_marker())
                 .any(|m| m.marker == marker)
         })
     }