Drop the lifetime from Circuit

src/circuit.rs

@@ -30,9 +30,11 @@ pub use hugr::{Node, Port, Wire};
 // - Vertical slice iterator
 // - Gate count map
 // - Depth
-pub trait Circuit<'circ>: HugrView {
+pub trait Circuit: HugrView {
     /// An iterator over the commands in the circuit.
-    type Commands: Iterator<Item = Command>;
+    type Commands<'a>: Iterator<Item = Command>
+    where
+        Self: 'a;
 
     /// An iterator over the commands applied to an unit.
     type UnitCommands: Iterator<Item = Command>;
@@ -65,10 +67,10 @@ pub trait Circuit<'circ>: HugrView {
     /// Returns all the commands in the circuit, in some topological order.
     ///
     /// Ignores the Input and Output nodes.
-    fn commands(&'circ self) -> Self::Commands;
+    fn commands(&self) -> Self::Commands<'_>;
 
     /// Returns all the commands applied to the given unit, in order.
-    fn unit_commands(&'circ self) -> Self::UnitCommands;
+    fn unit_commands(&self) -> Self::UnitCommands;
 
     /// Returns the [`NodeType`] of a command.
     fn command_nodetype(&self, command: &Command) -> &NodeType {
@@ -84,11 +86,11 @@ pub trait Circuit<'circ>: HugrView {
     fn num_gates(&self) -> usize;
 }
 
-impl<'circ, T> Circuit<'circ> for T
+impl<T> Circuit for T
 where
-    T: 'circ + HugrView,
+    T: HugrView,
 {
-    type Commands = CommandIterator<'circ, T>;
+    type Commands<'a> = CommandIterator<'a, T> where Self: 'a;
     type UnitCommands = std::iter::Empty<Command>;
 
     #[inline]
@@ -126,12 +128,12 @@ where
         }
     }
 
-    fn commands(&'circ self) -> Self::Commands {
+    fn commands(&self) -> Self::Commands<'_> {
         // Traverse the circuit in topological order.
         CommandIterator::new(self)
     }
 
-    fn unit_commands(&'circ self) -> Self::UnitCommands {
+    fn unit_commands(&self) -> Self::UnitCommands {
         // TODO Can we associate linear i/o with the corresponding unit without
         // doing the full toposort?
         unimplemented!()

src/circuit/command.rs

@@ -59,7 +59,7 @@ pub struct CommandIterator<'circ, Circ> {
 
 impl<'circ, Circ> CommandIterator<'circ, Circ>
 where
-    Circ: Circuit<'circ>,
+    Circ: Circuit,
 {
     /// Create a new iterator over the commands of a circuit.
     pub(super) fn new(circ: &'circ Circ) -> Self {
@@ -157,7 +157,7 @@ where
 
 impl<'circ, Circ> Iterator for CommandIterator<'circ, Circ>
 where
-    Circ: Circuit<'circ>,
+    Circ: Circuit,
 {
     type Item = Command;
 
@@ -181,7 +181,7 @@ where
     }
 }
 
-impl<'circ, Circ> FusedIterator for CommandIterator<'circ, Circ> where Circ: Circuit<'circ> {}
+impl<'circ, Circ> FusedIterator for CommandIterator<'circ, Circ> where Circ: Circuit {}
 
 #[cfg(test)]
 mod test {

src/json.rs

@@ -38,7 +38,7 @@ pub trait TKETDecode: Sized {
     /// Convert the serialized circuit to a [`Hugr`].
     fn decode(self) -> Result<Hugr, Self::DecodeError>;
     /// Convert a [`Hugr`] to a new serialized circuit.
-    fn encode<'circ>(circuit: &'circ impl Circuit<'circ>) -> Result<Self, Self::EncodeError>;
+    fn encode(circuit: &impl Circuit) -> Result<Self, Self::EncodeError>;
 }
 
 impl TKETDecode for SerialCircuit {
@@ -60,7 +60,7 @@ impl TKETDecode for SerialCircuit {
         Ok(decoder.finish())
     }
 
-    fn encode<'circ>(circ: &'circ impl Circuit<'circ>) -> Result<Self, Self::EncodeError> {
+    fn encode(circ: &impl Circuit) -> Result<Self, Self::EncodeError> {
         let mut encoder = JsonEncoder::new(circ);
         for com in circ.commands() {
             let optype = circ.command_optype(&com);

src/json/encoder.rs

@@ -41,7 +41,7 @@ pub(super) struct JsonEncoder {
 
 impl JsonEncoder {
     /// Create a new [`JsonEncoder`] from a [`Circuit`].
-    pub fn new<'circ>(circ: &impl Circuit<'circ>) -> Self {
+    pub fn new(circ: &impl Circuit) -> Self {
         let name = circ.name().map(str::to_string);
 
         // Compute the linear qubit and bit registers. Each one have independent

src/portmatching/matcher.rs

@@ -67,7 +67,7 @@ pub struct CircuitMatch<'a, 'p, C> {
     pub(super) root: Node,
 }
 
-impl<'a, 'p, C: Circuit<'a> + Clone> CircuitMatch<'a, 'p, C> {
+impl<'a, 'p, C: Circuit + Clone> CircuitMatch<'a, 'p, C> {
     /// Create a pattern match from the image of a pattern root.
     ///
     /// This checks at construction time that the match is convex. This will
@@ -132,7 +132,7 @@ impl<'a, 'p, C: Circuit<'a> + Clone> CircuitMatch<'a, 'p, C> {
     }
 }
 
-impl<'a, 'p, C: Circuit<'a>> Debug for CircuitMatch<'a, 'p, C> {
+impl<'a, 'p, C: Circuit> Debug for CircuitMatch<'a, 'p, C> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("CircuitMatch")
             .field("root", &self.root)
@@ -187,7 +187,7 @@ impl CircuitMatcher {
     }
 
     /// Find all convex pattern matches in a circuit.
-    pub fn find_matches<'a, 'm, C: Circuit<'a> + Clone>(
+    pub fn find_matches<'a, 'm, C: Circuit + Clone>(
         &'m self,
         circuit: &'a C,
     ) -> Vec<CircuitMatch<'a, 'm, C>> {
@@ -199,7 +199,7 @@ impl CircuitMatcher {
     }
 
     /// Find all convex pattern matches in a circuit rooted at a given node.
-    fn find_rooted_matches<'a, 'm, C: Circuit<'a> + Clone>(
+    fn find_rooted_matches<'a, 'm, C: Circuit + Clone>(
         &'m self,
         circ: &'a C,
         root: Node,
@@ -329,8 +329,8 @@ fn compatible_offsets((_, pout): &(Port, Port), (pin, _): &(Port, Port)) -> bool
 }
 
 /// Check if an edge `e` is valid in a portgraph `g` without weights.
-pub(crate) fn validate_unweighted_edge<'circ>(
-    circ: &impl Circuit<'circ>,
+pub(crate) fn validate_unweighted_edge(
+    circ: &impl Circuit,
 ) -> impl for<'a> Fn(Node, &'a PEdge) -> Option<Node> + '_ {
     move |src, &(src_port, tgt_port)| {
         let (next_node, _) = circ
@@ -341,8 +341,8 @@ pub(crate) fn validate_unweighted_edge<'circ>(
 }
 
 /// Check if a node `n` is valid in a weighted portgraph `g`.
-pub(crate) fn validate_weighted_node<'circ>(
-    circ: &impl Circuit<'circ>,
+pub(crate) fn validate_weighted_node(
+    circ: &impl Circuit,
 ) -> impl for<'a> Fn(Node, &PNode) -> bool + '_ {
     move |v, prop| {
         let v_weight = MatchOp::try_from(circ.get_optype(v).clone());

src/portmatching/pattern.rs

@@ -28,9 +28,7 @@ pub struct CircuitPattern {
 
 impl CircuitPattern {
     /// Construct a pattern from a circuit.
-    pub fn try_from_circuit<'circ, C: Circuit<'circ>>(
-        circuit: &'circ C,
-    ) -> Result<Self, InvalidPattern> {
+    pub fn try_from_circuit<C: Circuit>(circuit: &C) -> Result<Self, InvalidPattern> {
         if circuit.num_gates() == 0 {
             return Err(InvalidPattern::EmptyCircuit);
         }
@@ -74,11 +72,7 @@ impl CircuitPattern {
     }
 
     /// Compute the map from pattern nodes to circuit nodes in `circ`.
-    pub fn get_match_map<'a, C: Circuit<'a>>(
-        &self,
-        root: Node,
-        circ: &C,
-    ) -> Option<HashMap<Node, Node>> {
+    pub fn get_match_map<C: Circuit>(&self, root: Node, circ: &C) -> Option<HashMap<Node, Node>> {
         let single_matcher = SinglePatternMatcher::from_pattern(self.pattern.clone());
         single_matcher
             .get_match_map(