Remove unused `BuiltinLintDiag` variant `InnerAttributeUnstable`

This variant doesn't appear to have ever been used.

There's a matching message in `rustc_resolve`, that used to have a FIXME
for porting it to the new diagnostic infrastructure, but that message is
using `feature_err`, which doesn't use buffered lints. Thus, even when
that does get ported, it won't use `BuiltinLintDiag`.

3 files changed, 0 insertions, 18 deletions

diff --git a/compiler/rustc_lint/messages.ftl b/compiler/rustc_lint/messages.ftl
index 8f5043862aa..fc3b0cf2c56 100644
--- a/compiler/rustc_lint/messages.ftl
+++ b/compiler/rustc_lint/messages.ftl
@@ -205,8 +205,6 @@ lint_confusable_identifier_pair = found both `{$existing_sym}` and `{$sym}` as i
     .current_use = this identifier can be confused with `{$existing_sym}`
     .other_use = other identifier used here
 
-lint_custom_inner_attribute_unstable = custom inner attributes are unstable
-
 lint_dangling_pointers_from_locals = a dangling pointer will be produced because the local variable `{$local_var_name}` will be dropped
     .ret_ty = return type of the {$fn_kind} is `{$ret_ty}`
     .local_var = `{$local_var_name}` is part the {$fn_kind} and will be dropped at the end of the {$fn_kind}
@@ -427,8 +425,6 @@ lint_improper_ctypes_union_non_exhaustive = this union is non-exhaustive
 lint_incomplete_include =
     include macro expected single expression in source
 
-lint_inner_macro_attribute_unstable = inner macro attributes are unstable
-
 lint_invalid_asm_label_binary = avoid using labels containing only the digits `0` and `1` in inline assembly
     .label = use a different label that doesn't start with `0` or `1`
     .help = start numbering with `2` instead
diff --git a/compiler/rustc_lint/src/early/diagnostics.rs b/compiler/rustc_lint/src/early/diagnostics.rs
index 5f5e1b322bc..09e474963ff 100644
--- a/compiler/rustc_lint/src/early/diagnostics.rs
+++ b/compiler/rustc_lint/src/early/diagnostics.rs
@@ -463,12 +463,6 @@ pub fn decorate_builtin_lint(
             }
             .decorate_lint(diag)
         }
-        BuiltinLintDiag::InnerAttributeUnstable { is_macro } => if is_macro {
-            lints::InnerAttributeUnstable::InnerMacroAttribute
-        } else {
-            lints::InnerAttributeUnstable::CustomInnerAttribute
-        }
-        .decorate_lint(diag),
         BuiltinLintDiag::OutOfScopeMacroCalls { span, path, location } => {
             lints::OutOfScopeMacroCalls { span, path, location }.decorate_lint(diag)
         }
diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs
index 408774468b4..32bd7e263b0 100644
--- a/compiler/rustc_lint/src/lints.rs
+++ b/compiler/rustc_lint/src/lints.rs
@@ -2679,14 +2679,6 @@ pub(crate) struct IllFormedAttributeInput {
 }
 
 #[derive(LintDiagnostic)]
-pub(crate) enum InnerAttributeUnstable {
-    #[diag(lint_inner_macro_attribute_unstable)]
-    InnerMacroAttribute,
-    #[diag(lint_custom_inner_attribute_unstable)]
-    CustomInnerAttribute,
-}
-
-#[derive(LintDiagnostic)]
 #[diag(lint_unknown_diagnostic_attribute)]
 pub(crate) struct UnknownDiagnosticAttribute {
     #[subdiagnostic]