merge recommended changes

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>

Author: richard-uk1

compiler/rustc_lexer/src/lib.rs

@@ -688,7 +688,7 @@ impl Cursor<'_> {
                             }
                         }
                         ('e' | 'E', '0'..='9' | '+' | '-') => {
-                            // definitely an exponent
+                            // Definitely an exponent (which still can be empty).
                             self.bump();
                             empty_exponent = !self.eat_float_exponent();
                             suffix_start = self.pos_within_token();
@@ -700,7 +700,7 @@ impl Cursor<'_> {
                 (Float { base, empty_exponent }, suffix_start)
             }
             ('e' | 'E', '_') => {
-                // see above bock for similar apporach
+                // See above block for similar approach.
                 let non_exponent_suffix_start = self.pos_within_token();
                 self.bump();
                 while matches!(self.first(), '_') {
@@ -718,7 +718,7 @@ impl Cursor<'_> {
                 }
             }
             ('e' | 'E', '0'..='9' | '+' | '-') => {
-                // definitely an exponent
+                // // Definitely an exponent (which still can be empty).
                 self.bump();
                 let empty_exponent = !self.eat_float_exponent();
                 let suffix_start = self.pos_within_token();
@@ -978,7 +978,7 @@ impl Cursor<'_> {
         }
     }
 
-    /// Returns `true` if a digit was consumed (rather than just '_')
+    /// Returns `true` if a digit was consumed (rather than just '_'s).
     fn eat_decimal_digits(&mut self) -> bool {
         let mut has_digits = false;
         loop {

compiler/rustc_session/src/errors.rs

@@ -377,7 +377,7 @@ pub fn report_lit_error(
         s.len() > 1 && s.starts_with(first_chars) && s[1..].chars().all(|c| c.is_ascii_digit())
     }
 
-    fn looks_like_exponent(s: &str) -> bool {
+    fn looks_like_empty_exponent(s: &str) -> bool {
         s.len() == 1 && matches!(s.chars().next(), Some('e' | 'E'))
     }
 
@@ -413,7 +413,7 @@ pub fn report_lit_error(
             if looks_like_width_suffix(&['i', 'u'], suf) {
                 // If it looks like a width, try to be helpful.
                 dcx.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() })
-            } else if looks_like_exponent(suf) {
+            } else if looks_like_empty_exponent(suf) {
                 dcx.emit_err(EmptyFloatExponent { span })
             } else if let Some(fixed) = fix_base_capitalisation(lit.symbol.as_str(), suf) {
                 dcx.emit_err(InvalidNumLiteralBasePrefix { span, fixed })
@@ -426,7 +426,7 @@ pub fn report_lit_error(
             if looks_like_width_suffix(&['f'], suf) {
                 // If it looks like a width, try to be helpful.
                 dcx.emit_err(InvalidFloatLiteralWidth { span, width: suf[1..].to_string() })
-            } else if looks_like_exponent(suf) {
+            } else if looks_like_empty_exponent(suf) {
                 dcx.emit_err(EmptyFloatExponent { span })
             } else {
                 dcx.emit_err(InvalidFloatLiteralSuffix { span, suffix: suf.to_string() })