Rollup merge of rust-lang#125829 - petrochenkov:upctxt2, r=michaelwoerister

rustc_span: Add conveniences for working with span formats

This is the refactoring part of rust-lang#125017.

Author: matthiaskrgr

compiler/rustc_expand/src/mbe/transcribe.rs

@@ -30,7 +30,7 @@ impl MutVisitor for Marker {
         // it's some advanced case with macro-generated macros. So if we cache the marked version
         // of that context once, we'll typically have a 100% cache hit rate after that.
         let Marker(expn_id, transparency, ref mut cache) = *self;
-        span.update_ctxt(|ctxt| {
+        *span = span.map_ctxt(|ctxt| {
             *cache
                 .entry(ctxt)
                 .or_insert_with(|| ctxt.apply_mark(expn_id.to_expn_id(), transparency))

compiler/rustc_span/src/lib.rs

@@ -520,6 +520,7 @@ impl SpanData {
     pub fn with_hi(&self, hi: BytePos) -> Span {
         Span::new(self.lo, hi, self.ctxt, self.parent)
     }
+    /// Avoid if possible, `Span::map_ctxt` should be preferred.
     #[inline]
     fn with_ctxt(&self, ctxt: SyntaxContext) -> Span {
         Span::new(self.lo, self.hi, ctxt, self.parent)
@@ -576,9 +577,8 @@ impl Span {
         self.data().with_hi(hi)
     }
     #[inline]
-    pub fn with_ctxt(mut self, ctxt: SyntaxContext) -> Span {
-        self.update_ctxt(|_| ctxt);
-        self
+    pub fn with_ctxt(self, ctxt: SyntaxContext) -> Span {
+        self.map_ctxt(|_| ctxt)
     }
     #[inline]
     pub fn parent(self) -> Option<LocalDefId> {
@@ -1059,9 +1059,8 @@ impl Span {
     }
 
     #[inline]
-    pub fn apply_mark(mut self, expn_id: ExpnId, transparency: Transparency) -> Span {
-        self.update_ctxt(|ctxt| ctxt.apply_mark(expn_id, transparency));
-        self
+    pub fn apply_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span {
+        self.map_ctxt(|ctxt| ctxt.apply_mark(expn_id, transparency))
     }
 
     #[inline]
@@ -1109,15 +1108,13 @@ impl Span {
     }
 
     #[inline]
-    pub fn normalize_to_macros_2_0(mut self) -> Span {
-        self.update_ctxt(|ctxt| ctxt.normalize_to_macros_2_0());
-        self
+    pub fn normalize_to_macros_2_0(self) -> Span {
+        self.map_ctxt(|ctxt| ctxt.normalize_to_macros_2_0())
     }
 
     #[inline]
-    pub fn normalize_to_macro_rules(mut self) -> Span {
-        self.update_ctxt(|ctxt| ctxt.normalize_to_macro_rules());
-        self
+    pub fn normalize_to_macro_rules(self) -> Span {
+        self.map_ctxt(|ctxt| ctxt.normalize_to_macro_rules())
     }
 }