clippy: don't use .iter and .iter_mut where not necessary

Also a style thing, but makes the code more idiomatic.

Author: apoelstra

Cargo.toml

@@ -71,7 +71,7 @@ enum_glob_use = "allow"
 expl_impl_clone_on_copy = "warn"
 explicit_deref_methods = "warn"
 explicit_into_iter_loop = "warn"
-explicit_iter_loop = "allow"
+explicit_iter_loop = "warn"
 filter_map_next = "warn"
 flat_map_option = "allow"
 float_cmp = "warn"

src/num.rs

@@ -298,7 +298,7 @@ impl fmt::Display for U256 {
             is_zero = true;
 
             // Divide by 10, starting at the most significant bytes
-            for byte in bytes.iter_mut() {
+            for byte in &mut bytes {
                 let value = carry * 256 + u32::from(*byte);
                 *byte = (value / 10) as u8;
                 carry = value % 10;

src/serde.rs

@@ -144,7 +144,7 @@ impl<'a> Serialize for WitnessMapSerializer<'a> {
         S: Serializer,
     {
         let mut map = serializer.serialize_map(Some(self.0.len()))?;
-        for (name, value) in self.0.iter() {
+        for (name, value) in self.0 {
             map.serialize_entry(name.as_inner(), &ValueMapSerializer(value))?;
         }
         map.end()

src/value.rs

@@ -934,7 +934,7 @@ impl ValueConstructible for StructuralValue {
 
     fn array<I: IntoIterator<Item = Self>>(elements: I, ty: Self::Type) -> Self {
         let elements: Vec<Self> = elements.into_iter().collect();
-        for element in elements.iter() {
+        for element in &elements {
             assert!(
                 element.is_of_type(&ty),
                 "Element {element} is not of expected type {ty}"
@@ -954,7 +954,7 @@ impl ValueConstructible for StructuralValue {
             elements.len() < bound.get(),
             "There must be fewer list elements than the bound {bound}"
         );
-        for element in elements.iter() {
+        for element in &elements {
             assert!(
                 element.is_of_type(&ty),
                 "Element {element} is not of expected type {ty}"