clippy: trivial stuff

I split out the previous lint fix because touching boolean expressions always
makes me nervous. These ones are mechanical changes that do not make me nervous.

Author: apoelstra

Cargo.toml

@@ -91,7 +91,7 @@ copy_iterator = "warn"
 default_trait_access = "warn"
 doc_link_with_quotes = "warn"
 doc_markdown = "warn"
-empty_enum = "warn"
+empty_enums = "warn"
 enum_glob_use = "warn"
 expl_impl_clone_on_copy = "warn"
 explicit_deref_methods = "warn"
@@ -173,7 +173,7 @@ struct_field_names = "warn"
 too_many_lines = "allow" # FIXME 14 triggers for this lint; probably most should be fixed
 transmute_ptr_to_ptr = "warn"
 trivially_copy_pass_by_ref = "warn"
-unchecked_duration_subtraction = "warn"
+unchecked_time_subtraction = "warn"
 unicode_not_nfc = "warn"
 unnecessary_box_returns = "warn"
 unnecessary_join = "warn"

src/pset/mod.rs

@@ -360,11 +360,11 @@ impl PartiallySignedTransaction {
 
         self.global.merge(other.global)?;
 
-        for (self_input, other_input) in self.inputs.iter_mut().zip(other.inputs.into_iter()) {
+        for (self_input, other_input) in self.inputs.iter_mut().zip(other.inputs) {
             self_input.merge(other_input)?;
         }
 
-        for (self_output, other_output) in self.outputs.iter_mut().zip(other.outputs.into_iter()) {
+        for (self_output, other_output) in self.outputs.iter_mut().zip(other.outputs) {
             self_output.merge(other_output)?;
         }
 

src/pset/serialize.rs

@@ -186,10 +186,8 @@ impl Deserialize for KeySource {
 
         let mut d = &bytes[4..];
         while !d.is_empty() {
-            match u32::consensus_decode(&mut d) {
-                Ok(index) => dpath.push(index.into()),
-                Err(e) => return Err(e),
-            }
+            let index = u32::consensus_decode(&mut d)?;
+            dpath.push(index.into());
         }
 
         Ok((fprint, dpath.into()))