fix: improve message for inactive weak optional feature with edition2024

Author: linyihai

src/cargo/core/summary.rs

@@ -304,6 +304,13 @@ fn build_feature_map(
 
                     // Validation of the feature name will be performed in the resolver.
                     if !is_any_dep {
+                        // editon2024 stops expose implicit features, which will strip weak optional dependencies from `dependencies`
+                        if *weak {
+                            bail!(
+                                "feature `{feature}` includes `{fv}`, activate it in a feature with `dep:{dep_name}` if `{dep_name}` is an enabled dependency"                               
+                            );
+                        }
+
                         bail!(
                             "feature `{}` includes `{}`, but `{}` is not a dependency",
                             feature,

tests/testsuite/lints/unused_optional_dependencies.rs

@@ -188,7 +188,7 @@ fn inactive_weak_optional_dep() {
 error: failed to parse manifest at `[ROOT]/foo/Cargo.toml`
 
 Caused by:
-  feature `feat` includes `dep?/feat`, but `dep` is not a dependency
+  feature `feat` includes `dep?/feat`, activate it in a feature with `dep:dep` if `dep` is an enabled dependency
 ",
         )
         .run();
@@ -221,7 +221,7 @@ Caused by:
 error: failed to parse manifest at `[ROOT]/foo/Cargo.toml`
 
 Caused by:
-  feature `feat` includes `dep?/feat`, but `dep` is not a dependency
+  feature `feat` includes `dep?/feat`, activate it in a feature with `dep:dep` if `dep` is an enabled dependency
 ",
         )
         .run();