fix(features): When feature activates a typo, suggest alt

Author: epage

src/cargo/core/summary.rs

@@ -1,4 +1,5 @@
 use crate::core::{Dependency, PackageId, SourceId};
+use crate::util::closest_msg;
 use crate::util::interning::InternedString;
 use crate::util::CargoResult;
 use anyhow::bail;
@@ -241,9 +242,10 @@ fn build_feature_map(
                 Feature(f) => {
                     if !features.contains_key(f) {
                         if !is_any_dep {
+                            let closest = closest_msg(f, features.keys(), |k| k, "feature");
                             bail!(
                                 "feature `{feature}` includes `{fv}` which is neither a dependency \
-                                 nor another feature"
+                                 nor another feature{closest}"
                               );
                         }
                         if is_optional_dep {

tests/testsuite/features.rs

@@ -32,6 +32,8 @@ fn feature_activates_missing_feature() {
 Caused by:
   feature `bar` includes `baz` which is neither a dependency nor another feature
 
+  [HELP] a feature with a similar name exists: `bar`
+
 "#]])
         .run();
 }
@@ -64,6 +66,8 @@ fn feature_activates_typoed_feature() {
 Caused by:
   feature `bar` includes `baz` which is neither a dependency nor another feature
 
+  [HELP] a feature with a similar name exists: `bar`
+
 "#]])
         .run();
 }

tests/testsuite/features_namespaced.rs

@@ -75,6 +75,8 @@ fn namespaced_invalid_feature() {
 Caused by:
   feature `bar` includes `baz` which is neither a dependency nor another feature
 
+  [HELP] a feature with a similar name exists: `bar`
+
 "#]])
         .run();
 }