[refactor] resolve_extension_ops: take an ExtensionRegistry (#520)

This turns out to be pretty trivial, as ExtensionRegistry looks exactly
the same as HashMap as far as this code is concerned. Most of the effort
here is in fixing up imports and doclinks.

This addresses the first (easy) part of #508 but the second remains as
an issue/question for discussion, not attempting to resolve that here.

src/ops/custom.rs

@@ -1,15 +1,14 @@
 //! Extensible operations.
 
 use smol_str::SmolStr;
-use std::collections::HashMap;
 use std::sync::Arc;
 use thiserror::Error;
 
-use crate::extension::{ExtensionId, OpDef, SignatureError};
+use crate::extension::{ExtensionId, ExtensionRegistry, OpDef, SignatureError};
 use crate::hugr::hugrmut::sealed::HugrMutInternals;
 use crate::hugr::{HugrView, NodeType};
 use crate::types::{type_param::TypeArg, FunctionType, SignatureDescription};
-use crate::{Extension, Hugr, Node};
+use crate::{Hugr, Node};
 
 use super::tag::OpTag;
 use super::{LeafOp, OpName, OpTrait, OpType};
@@ -19,8 +18,12 @@ use super::{LeafOp, OpName, OpTrait, OpType};
 #[serde(into = "OpaqueOp", from = "OpaqueOp")]
 pub enum ExternalOp {
     /// When we've found (loaded) the [Extension] definition and identified the [OpDef]
+    ///
+    /// [Extension]: crate::Extension
     Extension(ExtensionOp),
     /// When we either haven't tried to identify the [Extension] or failed to find it.
+    ///
+    /// [Extension]: crate::Extension
     Opaque(OpaqueOp),
 }
 
@@ -95,7 +98,9 @@ impl OpTrait for ExternalOp {
 }
 
 /// An operation defined by an [OpDef] from a loaded [Extension].
-// Note *not* Serializable: container (ExternalOp) is serialized as an OpaqueOp instead.
+/// Note *not* Serializable: container ([ExternalOp]) is serialized as an [OpaqueOp] instead.
+///
+/// [Extension]: crate::Extension
 #[derive(Clone, Debug)]
 pub struct ExtensionOp {
     def: Arc<OpDef>,
@@ -216,13 +221,13 @@ impl OpaqueOp {
 #[allow(dead_code)]
 pub fn resolve_extension_ops(
     h: &mut Hugr,
-    extension_registry: &HashMap<SmolStr, Extension>,
+    extension_registry: &ExtensionRegistry,
 ) -> Result<(), CustomOpError> {
     let mut replacements = Vec::new();
     for n in h.nodes() {
         if let OpType::LeafOp(LeafOp::CustomOp(op)) = h.get_optype(n) {
             if let ExternalOp::Opaque(opaque) = op.as_ref() {
-                if let Some(r) = extension_registry.get(&*opaque.extension) {
+                if let Some(r) = extension_registry.get(&opaque.extension) {
                     // Fail if the Extension was found but did not have the expected operation
                     let Some(def) = r.get_op(&opaque.op_name) else {
                         return Err(CustomOpError::OpNotFoundInExtension(