From 14e86eb7d93ebda57d2008ae37e88ac2a0604570 Mon Sep 17 00:00:00 2001
From: Veera <sveera.2001@gmail.com>
Date: Mon, 2 Sep 2024 12:43:35 -0400
Subject: Add Suggestions for Misspelled Keywords

This PR detects misspelled keywords using two heuristics:

1. Lowercasing the unexpected identifier.
2. Using edit distance to find a keyword similar to the unexpected identifier.

However, it does not detect each and every misspelled keyword to
minimize false positives and ambiguities. More details about the
implementation can be found in the comments.
---
 compiler/rustc_span/src/symbol.rs | 42 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

(limited to 'compiler/rustc_span')

diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 34765209605..cabbdb02092 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -20,7 +20,8 @@ mod tests;
 
 // The proc macro code for this is in `compiler/rustc_macros/src/symbols.rs`.
 symbols! {
-    // If you modify this list, adjust `is_special` and `is_used_keyword`/`is_unused_keyword`.
+    // If you modify this list, adjust `is_special`, `is_used_keyword`/`is_unused_keyword`
+    // and `AllKeywords`.
     // But this should rarely be necessary if the keywords are kept in alphabetic order.
     Keywords {
         // Special reserved identifiers used internally for elided lifetimes,
@@ -2577,3 +2578,42 @@ impl Ident {
         self.name.can_be_raw() && self.is_reserved()
     }
 }
+
+/// An iterator over all the keywords in Rust.
+#[derive(Copy, Clone)]
+pub struct AllKeywords {
+    curr_idx: u32,
+    end_idx: u32,
+}
+
+impl AllKeywords {
+    /// Initialize a new iterator over all the keywords.
+    ///
+    /// *Note:* Please update this if a new keyword is added beyond the current
+    /// range.
+    pub fn new() -> Self {
+        AllKeywords { curr_idx: kw::Empty.as_u32(), end_idx: kw::Yeet.as_u32() }
+    }
+
+    /// Collect all the keywords in a given edition into a vector.
+    pub fn collect_used(&self, edition: impl Copy + FnOnce() -> Edition) -> Vec<Symbol> {
+        self.filter(|&keyword| {
+            keyword.is_used_keyword_always() || keyword.is_used_keyword_conditional(edition)
+        })
+        .collect()
+    }
+}
+
+impl Iterator for AllKeywords {
+    type Item = Symbol;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.curr_idx <= self.end_idx {
+            let keyword = Symbol::new(self.curr_idx);
+            self.curr_idx += 1;
+            Some(keyword)
+        } else {
+            None
+        }
+    }
+}
-- 
cgit 1.4.1-3-g733a5