Remove expect, use collect, add must_use

src/meta.rs

@@ -11,6 +11,7 @@ pub struct Field {
 
 impl Field {
     /// Create a new empty field metadata
+    #[must_use]
     pub const fn empty() -> Self {
         Self {
             meta: String::new(),
@@ -47,16 +48,19 @@ impl Field {
     }
 
     /// Get the metadata of this field
+    #[must_use]
     pub fn get_meta(&self) -> &str {
         self.meta.as_str()
     }
 
     /// Return whether this field has inner fields
+    #[must_use]
     pub fn has_fields(&self) -> bool {
         self.fields.is_some()
     }
 
     /// Get a reference to the inner fields of this field, if it has any
+    #[must_use]
     pub fn fields(&self) -> Option<&Fields> {
         self.fields.as_ref()
     }
@@ -75,6 +79,7 @@ pub struct Fields {
 
 impl Fields {
     /// Return a new, empty metadata field map
+    #[must_use]
     pub fn new() -> Self {
         Self::default()
     }
@@ -99,7 +104,7 @@ impl Fields {
 impl<K: Into<String>> FromIterator<(K, Field)> for Fields {
     fn from_iter<T: IntoIterator<Item = (K, Field)>>(iter: T) -> Self {
         Self {
-            fields: HashMap::from_iter(iter.into_iter().map(|(k, v)| (k.into(), v))),
+            fields: iter.into_iter().map(|(k, v)| (k.into(), v)).collect(),
         }
     }
 }

src/ser/mod.rs

@@ -7,7 +7,7 @@ use unicode_ident::is_xid_continue;
 use crate::{
     error::{Error, Result},
     extensions::Extensions,
-    meta::Fields,
+    meta::{Field, Fields},
     options::Options,
     parse::{is_ident_first_char, is_ident_raw_char, is_whitespace_char, LargeSInt, LargeUInt},
 };
@@ -1341,14 +1341,11 @@ impl<'a, W: fmt::Write> ser::SerializeStruct for Compound<'a, W> {
             if let Some((ref config, _)) = self.ser.pretty {
                 let mut iter = self.ser.field_memory.iter();
 
-                let name = iter.next().expect(
-                    "is always at least one, because we push one at the beginning of this function",
-                );
-
+                let init = iter.next().and_then(|name| config.meta.get_field(name));
                 let field = iter
-                    .try_fold(config.meta.get_field(name), |field, name| {
+                    .try_fold(init, |field, name| {
                         field
-                            .and_then(|field| field.fields())
+                            .and_then(Field::fields)
                             .map(|fields| fields.get_field(name))
                     })
                     .flatten();