diff --git a/compiler/parse/src/header.rs b/compiler/parse/src/header.rs
index e289e15179..3bd83988ab 100644
--- a/compiler/parse/src/header.rs
+++ b/compiler/parse/src/header.rs
@@ -2,13 +2,10 @@ use crate::ast::{CommentOrNewline, Spaceable, StrLiteral, TypeAnnotation};
 use crate::blankspace::space0;
 use crate::ident::lowercase_ident;
 use crate::parser::{
-    ascii_char, optional, peek_utf8_char, specialize, unexpected_eof, Either, ParseResult, Parser,
-    Progress, Progress::*, State, SyntaxError,
+    ascii_char, optional, specialize, Either, Parser, Progress, Progress::*, State, SyntaxError,
 };
 use crate::string_literal;
-use bumpalo::collections::String;
 use bumpalo::collections::Vec;
-use bumpalo::Bump;
 use inlinable_string::InlinableString;
 use roc_region::all::Loc;
 
@@ -274,24 +271,22 @@ pub fn package_entry<'a>() -> impl Parser<'a, PackageEntry<'a>, SyntaxError<'a>>
 }
 
 pub fn package_or_path<'a>() -> impl Parser<'a, PackageOrPath<'a>, SyntaxError<'a>> {
-    map!(
-        either!(
+    one_of![
+        map!(
             specialize(
                 |e, r, c| SyntaxError::Expr(crate::parser::EExpr::Str(e, r, c)),
                 string_literal::parse()
             ),
+            PackageOrPath::Path
+        ),
+        map!(
             and!(
                 package_name(),
                 skip_first!(one_or_more!(ascii_char(b' ')), package_version())
-            )
-        ),
-        |answer| {
-            match answer {
-                Either::First(str_literal) => PackageOrPath::Path(str_literal),
-                Either::Second((name, version)) => PackageOrPath::Package(name, version),
-            }
-        }
-    )
+            ),
+            |(name, version)| { PackageOrPath::Package(name, version) }
+        )
+    ]
 }
 
 fn package_version<'a>() -> impl Parser<'a, Version<'a>, SyntaxError<'a>> {
@@ -300,45 +295,57 @@ fn package_version<'a>() -> impl Parser<'a, Version<'a>, SyntaxError<'a>> {
 
 #[inline(always)]
 pub fn package_name<'a>() -> impl Parser<'a, PackageName<'a>, SyntaxError<'a>> {
+    use encode_unicode::CharExt;
     // e.g. rtfeldman/blah
     //
     // Package names and accounts can be capitalized and can contain dashes.
     // They cannot contain underscores or other special characters.
     // They must be ASCII.
 
-    map!(
-        and!(
-            parse_package_part,
-            skip_first!(ascii_char(b'/'), parse_package_part)
-        ),
-        |(account, pkg)| { PackageName { account, pkg } }
-    )
-}
+    |_, mut state: State<'a>| match chomp_package_part(state.bytes) {
+        Err(progress) => Err((progress, SyntaxError::ConditionFailed, state)),
+        Ok(account) => {
+            let mut chomped = account.len();
+            if let Ok(('/', width)) = char::from_utf8_slice_start(&state.bytes[chomped..]) {
+                chomped += width;
+                match chomp_package_part(&state.bytes[chomped..]) {
+                    Err(progress) => Err((progress, SyntaxError::ConditionFailed, state)),
+                    Ok(pkg) => {
+                        chomped += pkg.len();
 
-fn parse_package_part<'a>(
-    arena: &'a Bump,
-    mut state: State<'a>,
-) -> ParseResult<'a, &'a str, SyntaxError<'a>> {
-    let mut part_buf = String::new_in(arena); // The current "part" (parts are dot-separated.)
+                        state.column += chomped as u16;
+                        state.bytes = &state.bytes[chomped..];
 
-    while !state.bytes.is_empty() {
-        match peek_utf8_char(&state) {
-            Ok((ch, bytes_parsed)) => {
-                if ch == '-' || ch.is_ascii_alphanumeric() {
-                    part_buf.push(ch);
-
-                    state = state.advance_without_indenting(bytes_parsed)?;
-                } else {
-                    let progress = Progress::progress_when(!part_buf.is_empty());
-                    return Ok((progress, part_buf.into_bump_str(), state));
+                        let value = PackageName { account, pkg };
+                        Ok((MadeProgress, value, state))
+                    }
                 }
-            }
-            Err(reason) => {
-                let progress = Progress::progress_when(!part_buf.is_empty());
-                return state.fail(arena, progress, reason);
+            } else {
+                Err((MadeProgress, SyntaxError::ConditionFailed, state))
             }
         }
     }
-
-    Err(unexpected_eof(arena, state, 0))
+}
+
+fn chomp_package_part<'a>(buffer: &'a [u8]) -> Result<&'a str, Progress> {
+    use encode_unicode::CharExt;
+
+    let mut chomped = 0;
+
+    while let Ok((ch, width)) = char::from_utf8_slice_start(&buffer[chomped..]) {
+        if ch == '-' || ch.is_ascii_alphanumeric() {
+            chomped += width;
+        } else {
+            // we're done
+            break;
+        }
+    }
+
+    if chomped == 0 {
+        Err(Progress::NoProgress)
+    } else {
+        let name = unsafe { std::str::from_utf8_unchecked(&buffer[..chomped]) };
+
+        Ok(name)
+    }
 }