Remove dead error code.

Author: cjgillot

compiler/rustc_error_codes/src/error_codes/E0698.md

@@ -1,9 +1,11 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 When using generators (or async) all type variables must be bound so a
 generator can be constructed.
 
 Erroneous code example:
 
-```edition2018,compile_fail,E0698
+```edition2018,compile_fail,E0282
 async fn bar<T>() -> () {}
 
 async fn foo() {

compiler/rustc_infer/src/errors/mod.rs

@@ -14,8 +14,7 @@ use rustc_span::{symbol::Ident, BytePos, Span};
 
 use crate::fluent_generated as fluent;
 use crate::infer::error_reporting::{
-    need_type_info::{GeneratorKindAsDiagArg, UnderspecifiedArgKind},
-    nice_region_error::placeholder_error::Highlighted,
+    need_type_info::UnderspecifiedArgKind, nice_region_error::placeholder_error::Highlighted,
     ObligationCauseAsDiagArg,
 };
 
@@ -86,16 +85,6 @@ pub struct AmbiguousReturn<'a> {
     pub multi_suggestions: Vec<SourceKindMultiSuggestion<'a>>,
 }
 
-#[derive(Diagnostic)]
-#[diag(infer_need_type_info_in_generator, code = "E0698")]
-pub struct NeedTypeInfoInGenerator<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub generator_kind: GeneratorKindAsDiagArg,
-    #[subdiagnostic]
-    pub bad_label: InferenceBadError<'a>,
-}
-
 // Used when a better one isn't available
 #[derive(Subdiagnostic)]
 #[label(infer_label_bad)]

compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs

@@ -1,5 +1,5 @@
 use crate::errors::{
-    AmbiguousImpl, AmbiguousReturn, AnnotationRequired, InferenceBadError, NeedTypeInfoInGenerator,
+    AmbiguousImpl, AmbiguousReturn, AnnotationRequired, InferenceBadError,
     SourceKindMultiSuggestion, SourceKindSubdiag,
 };
 use crate::infer::error_reporting::TypeErrCtxt;
@@ -595,39 +595,6 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
     }
 }
 
-impl<'tcx> InferCtxt<'tcx> {
-    pub fn need_type_info_err_in_generator(
-        &self,
-        kind: hir::GeneratorKind,
-        span: Span,
-        ty: ty::Term<'tcx>,
-    ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
-        let ty = self.resolve_vars_if_possible(ty);
-        let data = self.extract_inference_diagnostics_data(ty.into(), None);
-
-        NeedTypeInfoInGenerator {
-            bad_label: data.make_bad_error(span),
-            span,
-            generator_kind: GeneratorKindAsDiagArg(kind),
-        }
-        .into_diagnostic(&self.tcx.sess.parse_sess.span_diagnostic)
-    }
-}
-
-pub struct GeneratorKindAsDiagArg(pub hir::GeneratorKind);
-
-impl IntoDiagnosticArg for GeneratorKindAsDiagArg {
-    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
-        let kind = match self.0 {
-            hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Block) => "async_block",
-            hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Closure) => "async_closure",
-            hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Fn) => "async_fn",
-            hir::GeneratorKind::Gen => "generator",
-        };
-        rustc_errors::DiagnosticArgValue::Str(kind.into())
-    }
-}
-
 #[derive(Debug)]
 struct InferSource<'tcx> {
     span: Span,