Merge 'Kill unwrap() in macros' from Pekka Enberg

Closes #4004

Author: penberg

macros/src/atomic_enum.rs

@@ -123,9 +123,10 @@ pub(crate) fn derive_atomic_enum_inner(input: TokenStream) -> TokenStream {
                     }
                 }
             }
-            Fields::Unnamed(_) => {
+            Fields::Unnamed(fields) => {
                 // same strategy as above, but for tuple variants like `Write(bool)`
-                if is_bool_type(&variant.fields.iter().next().unwrap().ty) {
+                let field = &fields.unnamed[0];
+                if is_bool_type(&field.ty) {
                     if use_u16 {
                         quote! {
                             #name::#var_name(ref val) => {
@@ -186,8 +187,9 @@ pub(crate) fn derive_atomic_enum_inner(input: TokenStream) -> TokenStream {
                     }
                 }
             }
-            Fields::Unnamed(_) => {
-                if is_bool_type(&variant.fields.iter().next().unwrap().ty) {
+            Fields::Unnamed(fields) => {
+                let field = &fields.unnamed[0];
+                if is_bool_type(&field.ty) {
                     if use_u16 {
                         quote! { #disc => #name::#var_name((val >> 8) != 0) }
                     } else {

macros/src/ext/match_ignore_ascii_case.rs

@@ -86,19 +86,12 @@ pub fn match_ignore_ascci_case(input: TokenStream) -> TokenStream {
         let mut current = &mut paths;
 
         for b in keyword_b {
-            match current.sub_entries.get(&b) {
-                Some(_) => {
-                    current = current.sub_entries.get_mut(&b).unwrap();
-                }
-                None => {
-                    let new_entry = Box::new(PathEntry {
-                        result: None,
-                        sub_entries: HashMap::new(),
-                    });
-                    current.sub_entries.insert(b, new_entry);
-                    current = current.sub_entries.get_mut(&b).unwrap();
-                }
-            }
+            current = current.sub_entries.entry(b).or_insert_with(|| {
+                Box::new(PathEntry {
+                    result: None,
+                    sub_entries: HashMap::new(),
+                })
+            });
         }
 
         assert!(current.result.is_none());

macros/src/lib.rs

@@ -132,15 +132,17 @@ fn generate_get_description(
     }
 
     let enum_impl = format!(
-        "impl {enum_name}  {{ 
+        "impl {enum_name}  {{
      pub fn get_description(&self) -> Option<&str> {{
      match self {{
      {all_enum_arms}
      }}
      }}
      }}"
     );
-    enum_impl.parse().unwrap()
+    enum_impl
+        .parse()
+        .expect("generated code should be valid Rust")
 }
 
 /// Register your extension with 'core' by providing the relevant functions