From 00f6fe1b6cbb211c4396b306566816f91a4ed371 Mon Sep 17 00:00:00 2001
From: Esteban Küber <esteban@kuber.com.ar>
Date: Sat, 30 Aug 2025 16:24:26 +0000
Subject: On unused binding in pattern, suggest unit struct/variant with
 similar name

When encountering a typo in a pattern that gets interpreted as an unused binding, look for unit struct/variant of the same type as the binding:

```
error: unused variable: `Non`
  --> $DIR/binding-typo-2.rs:36:9
   |
LL |         Non => {}
   |         ^^^
   |
help: if this is intentional, prefix it with an underscore
   |
LL |         _Non => {}
   |         +
help: you might have meant to pattern match on the similarly named variant `None`
   |
LL -         Non => {}
LL +         std::prelude::v1::None => {}
   |
```
---
 compiler/rustc_passes/src/errors.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'compiler/rustc_passes/src/errors.rs')

diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 4fec6b0798a..ebd8f6fc820 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -1346,6 +1346,22 @@ pub(crate) struct UnusedVarRemoveFieldSugg {
 #[note]
 pub(crate) struct UnusedVarAssignedOnly {
     pub name: String,
+    #[subdiagnostic]
+    pub typo: Option<PatternTypo>,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(
+    passes_unused_var_typo,
+    style = "verbose",
+    applicability = "machine-applicable"
+)]
+pub(crate) struct PatternTypo {
+    #[suggestion_part(code = "{code}")]
+    pub span: Span,
+    pub code: String,
+    pub item_name: String,
+    pub kind: String,
 }
 
 #[derive(LintDiagnostic)]
@@ -1413,6 +1429,8 @@ pub(crate) struct UnusedVariableTryPrefix {
     #[subdiagnostic]
     pub sugg: UnusedVariableSugg,
     pub name: String,
+    #[subdiagnostic]
+    pub typo: Option<PatternTypo>,
 }
 
 #[derive(Subdiagnostic)]
-- 
cgit 1.4.1-3-g733a5