Rollup merge of #129626 - compiler-errors:explicit-named, r=fmease

Remove `ParamMode::ExplicitNamed`

This was introduced as a hack to improve a diagnostics suggestion in #61679. It was subsequently broken, but also it was an incomplete hack that I don't believe we need to support, so let's just remove it.

compiler/rustc_ast_lowering/src/item.rs

@@ -764,18 +764,7 @@ pub(super) fn lower_field_def(
         &mut self,
         (index, f): (usize, &FieldDef),
     ) -> hir::FieldDef<'hir> {
-        let ty = if let TyKind::Path(qself, path) = &f.ty.kind {
+        let ty = self.lower_ty(&f.ty, ImplTraitContext::Disallowed(ImplTraitPosition::FieldTy));
-            let t = self.lower_path_ty(
-                &f.ty,
-                qself,
-                path,
-                ParamMode::ExplicitNamed, // no `'_` in declarations (Issue #61124)
-                ImplTraitContext::Disallowed(ImplTraitPosition::FieldTy),
-            );
-            self.arena.alloc(t)
-        } else {
-            self.lower_ty(&f.ty, ImplTraitContext::Disallowed(ImplTraitPosition::FieldTy))
-        };
         let hir_id = self.lower_node_id(f.id);
         self.lower_attrs(hir_id, &f.attrs);
         hir::FieldDef {

compiler/rustc_ast_lowering/src/lib.rs

@@ -482,8 +482,6 @@ pub fn lower_to_hir(tcx: TyCtxt<'_>, (): ()) -> hir::Crate<'_> {
 enum ParamMode {
     /// Any path in a type context.
     Explicit,
-    /// Path in a type definition, where the anonymous lifetime `'_` is not allowed.
-    ExplicitNamed,
     /// The `module::Type` in `module::Type::method` in an expression.
     Optional,
 }