Add note to E0401

Author: estebank

compiler/rustc_resolve/messages.ftl

@@ -175,6 +175,7 @@ resolve_generic_params_from_outer_item =
     } from outer item
     .refer_to_type_directly = refer to the type directly here instead
     .suggestion = try introducing a local generic parameter here
+    .note = nested items are independent from their parent item for everything except for privacy and name resolution
 
 resolve_generic_params_from_outer_item_const = a `const` is a separate item from the item that contains it
 

compiler/rustc_resolve/src/errors.rs

@@ -11,6 +11,7 @@ use crate::{Res, fluent_generated as fluent};
 
 #[derive(Diagnostic)]
 #[diag(resolve_generic_params_from_outer_item, code = E0401)]
+#[note]
 pub(crate) struct GenericParamsFromOuterItem {
     #[primary_span]
     #[label]

tests/ui/const-generics/early/const-param-from-outer-fn.stderr

@@ -8,6 +8,7 @@ LL |     fn bar() -> u32 {
 LL |         X
    |         ^ use of generic parameter from outer item
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: try introducing a local generic parameter here
    |
 LL |     fn bar<X>() -> u32 {

tests/ui/delegation/target-expr.stderr

@@ -8,6 +8,8 @@ LL |     reuse Trait::static_method {
 LL |
 LL |         let _ = T::Default();
    |                 ^ use of generic parameter from outer item
+   |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 
 error[E0434]: can't capture dynamic environment in a fn item
   --> $DIR/target-expr.rs:26:17

tests/ui/error-codes/E0401.stderr

@@ -8,6 +8,7 @@ LL |     fn bfnr<U, V: Baz<U>, W: Fn()>(y: T) {
    |        |
    |        generic parameter used in this inner function
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: try introducing a local generic parameter here
    |
 LL |     fn bfnr<T, U, V: Baz<U>, W: Fn()>(y: T) {
@@ -25,6 +26,7 @@ LL |     fn baz<U,
 LL |            (y: T) {
    |                ^ use of generic parameter from outer item
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: try introducing a local generic parameter here
    |
 LL |     fn baz<T, U,
@@ -41,6 +43,7 @@ LL |         fn helper(sel: &Self) -> u8 {
    |            |
    |            `Self` used in this inner function
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: refer to the type directly here instead
    |
 LL -         fn helper(sel: &Self) -> u8 {

tests/ui/generics/enum-definition-with-outer-generic-parameter-5997.stderr

@@ -8,6 +8,7 @@ LL |     enum E { V(Z) }
    |          |
    |          generic parameter used in this inner enum
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: try introducing a local generic parameter here
    |
 LL |     enum E<Z> { V(Z) }

tests/ui/generics/generic-params-nested-fn-scope-error.stderr

@@ -8,6 +8,7 @@ LL |     fn bar(w: [U]) -> U {
    |        |
    |        generic parameter used in this inner function
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: try introducing a local generic parameter here
    |
 LL |     fn bar<U>(w: [U]) -> U {
@@ -23,6 +24,7 @@ LL |     fn bar(w: [U]) -> U {
    |        |
    |        generic parameter used in this inner function
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: try introducing a local generic parameter here
    |
 LL |     fn bar<U>(w: [U]) -> U {

tests/ui/generics/issue-98432.stderr

@@ -9,6 +9,7 @@ LL |         struct _Obligation where T:;
    |                |
    |                generic parameter used in this inner struct
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: try introducing a local generic parameter here
    |
 LL |         struct _Obligation<T> where T:;

tests/ui/resolve/bad-type-env-capture.stderr

@@ -8,6 +8,7 @@ LL |     fn bar(b: T) { }
    |        |
    |        generic parameter used in this inner function
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
 help: try introducing a local generic parameter here
    |
 LL |     fn bar<T>(b: T) { }

tests/ui/resolve/generic-params-from-outer-item-in-const-item.default.stderr

@@ -8,6 +8,7 @@ LL |     const K: u32 = T::C;
    |           |
    |           generic parameter used in this inner constant item
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
    = note: a `const` is a separate item from the item that contains it
 
 error[E0401]: can't use generic parameters from outer item
@@ -21,6 +22,7 @@ LL |         const I: u32 = T::C;
    |               |
    |               generic parameter used in this inner constant item
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
    = note: a `const` is a separate item from the item that contains it
 
 error[E0401]: can't use generic parameters from outer item
@@ -33,6 +35,7 @@ LL |     const _: u32 = T::C;
    |           |
    |           generic parameter used in this inner constant item
    |
+   = note: nested items are independent from their parent item for everything except for privacy and name resolution
    = note: a `const` is a separate item from the item that contains it
 
 error: aborting due to 3 previous errors