Use TokenKind::similar_tokens()

Author: FabianWolff

compiler/rustc_ast/src/token.rs

@@ -295,6 +295,7 @@ impl TokenKind {
         match *self {
             Comma => Some(vec![Dot, Lt, Semi]),
             Semi => Some(vec![Colon, Comma]),
+            FatArrow => Some(vec![Eq, RArrow]),
             _ => None,
         }
     }

compiler/rustc_parse/src/parser/expr.rs

@@ -2324,7 +2324,10 @@ impl<'a> Parser<'a> {
             let arrow_span = this.token.span;
             if let Err(mut err) = this.expect(&token::FatArrow) {
                 // We might have a `=>` -> `=` or `->` typo (issue #89396).
-                if let token::Eq | token::RArrow = this.token.kind {
+                if TokenKind::FatArrow
+                    .similar_tokens()
+                    .map_or(false, |similar_tokens| similar_tokens.contains(&this.token.kind))
+                {
                     err.span_suggestion(
                         this.token.span,
                         "try using a fat arrow here",