Rollup merge of #81849 - scottmcm:control-flow-comments, r=Mark-Simulacrum

[rust.git] / compiler / rustc_span / src / source_map.rs

diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index 2b429372dcffb2d2dd07a800bf4392b408739512..298c995b1660b1320ba7b055552855c8294241a8 100644 (file)
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -539,7 +539,7 @@ pub fn is_valid_span(&self, sp: Span) -> Result<(Loc, Loc), SpanLinesError> {
 
     pub fn is_line_before_span_empty(&self, sp: Span) -> bool {
         match self.span_to_prev_source(sp) {
-            Ok(s) => s.split('\n').last().map_or(false, |l| l.trim_start().is_empty()),
+            Ok(s) => s.rsplit_once('\n').unwrap_or(("", &s)).1.trim_start().is_empty(),
             Err(_) => false,
         }
     }
@@ -632,10 +632,11 @@ pub fn span_to_snippet(&self, sp: Span) -> Result<String, SpanSnippetError> {
     pub fn span_to_margin(&self, sp: Span) -> Option<usize> {
         match self.span_to_prev_source(sp) {
             Err(_) => None,
-            Ok(source) => source
-                .split('\n')
-                .last()
-                .map(|last_line| last_line.len() - last_line.trim_start().len()),
+            Ok(source) => {
+                let last_line = source.rsplit_once('\n').unwrap_or(("", &source)).1;
+
+                Some(last_line.len() - last_line.trim_start().len())
+            }
         }
     }
 
@@ -651,7 +652,7 @@ pub fn span_to_prev_source(&self, sp: Span) -> Result<String, SpanSnippetError>
     pub fn span_extend_to_prev_char(&self, sp: Span, c: char, accept_newlines: bool) -> Span {
         if let Ok(prev_source) = self.span_to_prev_source(sp) {
             let prev_source = prev_source.rsplit(c).next().unwrap_or("");
-            if !prev_source.is_empty() && (!prev_source.contains('\n') || accept_newlines) {
+            if !prev_source.is_empty() && (accept_newlines || !prev_source.contains('\n')) {
                 return sp.with_lo(BytePos(sp.lo().0 - prev_source.len() as u32));
             }
         }
@@ -673,7 +674,7 @@ pub fn span_extend_to_prev_str(&self, sp: Span, pat: &str, accept_newlines: bool
                 let prev_source = prev_source.rsplit(&pat).next().unwrap_or("").trim_start();
                 if prev_source.is_empty() && sp.lo().0 != 0 {
                     return sp.with_lo(BytePos(sp.lo().0 - 1));
-                } else if !prev_source.contains('\n') || accept_newlines {
+                } else if accept_newlines || !prev_source.contains('\n') {
                     return sp.with_lo(BytePos(sp.lo().0 - prev_source.len() as u32));
                 }
             }
@@ -693,7 +694,7 @@ pub fn span_to_next_source(&self, sp: Span) -> Result<String, SpanSnippetError>
     pub fn span_extend_to_next_char(&self, sp: Span, c: char, accept_newlines: bool) -> Span {
         if let Ok(next_source) = self.span_to_next_source(sp) {
             let next_source = next_source.split(c).next().unwrap_or("");
-            if !next_source.is_empty() && (!next_source.contains('\n') || accept_newlines) {
+            if !next_source.is_empty() && (accept_newlines || !next_source.contains('\n')) {
                 return sp.with_hi(BytePos(sp.hi().0 + next_source.len() as u32));
             }
         }