1 files changed, 32 insertions, 9 deletions

diff --git a/src/source.rs b/src/source.rs
index 82b54550..eaf94001 100644
--- a/src/source.rs
+++ b/src/source.rs
@@ -20,24 +20,24 @@ use codespan_reporting::files::{self, Files};
 
 /// A unique identifier for a loaded source file.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub struct SourceId(u32);
+pub struct SourceId(u16);
 
 impl SourceId {
     /// Create a new source id for a file that is not part of a store.
     pub const fn detached() -> Self {
-        Self(u32::MAX)
+        Self(u16::MAX)
     }
 
     /// Create a source id from the raw underlying value.
     ///
     /// This should only be called with values returned by
     /// [`into_raw`](Self::into_raw).
-    pub const fn from_raw(v: u32) -> Self {
+    pub const fn from_raw(v: u16) -> Self {
         Self(v)
     }
 
     /// Convert into the raw underlying value.
-    pub const fn into_raw(self) -> u32 {
+    pub const fn into_raw(self) -> u16 {
         self.0
     }
 }
@@ -108,7 +108,7 @@ impl SourceStore {
         }
 
         // No existing file yet.
-        let id = SourceId(self.sources.len() as u32);
+        let id = SourceId(self.sources.len() as u16);
         self.sources.push(SourceFile::new(id, path, src));
 
         // Register in file map if the path was known to the loader.
@@ -140,6 +140,13 @@ impl SourceStore {
     ) -> Range<usize> {
         self.sources[id.0 as usize].edit(replace, with)
     }
+
+    /// Map a span that points into this source store to a byte range.
+    ///
+    /// Panics if the span does not point into this source store.
+    pub fn range(&self, span: Span) -> Range<usize> {
+        self.get(span.source()).range(span)
+    }
 }
 
 /// A single source file.
@@ -160,10 +167,14 @@ impl SourceFile {
     pub fn new(id: SourceId, path: &Path, src: String) -> Self {
         let mut lines = vec![Line { byte_idx: 0, utf16_idx: 0 }];
         lines.extend(Line::iter(0, 0, &src));
+
+        let mut root = parse(&src);
+        root.number(id, 1);
+
         Self {
             id,
             path: path.normalize(),
-            root: parse(&src),
+            root,
             src,
             lines,
             rev: 0,
@@ -178,8 +189,8 @@ impl SourceFile {
     /// Create a source file with the same synthetic span for all nodes.
     pub fn synthesized(src: impl Into<String>, span: Span) -> Self {
         let mut file = Self::detached(src);
-        file.root.synthesize(Arc::new(span));
-        file.id = span.source;
+        file.root.synthesize(span);
+        file.id = span.source();
         file
     }
 
@@ -232,6 +243,7 @@ impl SourceFile {
         self.lines = vec![Line { byte_idx: 0, utf16_idx: 0 }];
         self.lines.extend(Line::iter(0, 0, &self.src));
         self.root = parse(&self.src);
+        self.root.number(self.id(), 1);
         self.rev = self.rev.wrapping_add(1);
     }
 
@@ -265,7 +277,9 @@ impl SourceFile {
         ));
 
         // Incrementally reparse the replaced range.
-        reparse(&mut self.root, &self.src, replace, with.len())
+        let range = reparse(&mut self.root, &self.src, replace, with.len());
+        self.root.number(self.id(), 1);
+        range
     }
 
     /// Get the length of the file in bytes.
@@ -284,6 +298,15 @@ impl SourceFile {
         self.lines.len()
     }
 
+    /// Map a span that points into this source file to a byte range.
+    ///
+    /// Panics if the span does not point into this source file.
+    pub fn range(&self, span: Span) -> Range<usize> {
+        self.root
+            .range(span, 0)
+            .expect("span does not point into this source file")
+    }
+
     /// Return the index of the UTF-16 code unit at the byte index.
     pub fn byte_to_utf16(&self, byte_idx: usize) -> Option<usize> {
         let line_idx = self.byte_to_line(byte_idx)?;