Auto merge of #119088 - George-lewis:glewis/suggest-upgrading-compiler, r=Nilstrieb

Suggest Upgrading Compiler for Gated Features

This PR addresses #117318

I have a few questions:

1. Do we want to specify the current version and release date of the compiler? I have added this in via environment variables, which I found in the code for the rustc cli where it handles the `--version` flag
  a. How can I handle the changing message in the tests?
3. Do we want to only show this message when the compiler is old?
  a. How can we determine when the compiler is old?

I'll wait until we figure out the message to bless the tests

compiler/rustc_hir_analysis/src/astconv/errors.rs

@@ -59,7 +59,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             if trait_segment.args().parenthesized == hir::GenericArgsParentheses::ParenSugar {
                 // For now, require that parenthetical notation be used only with `Fn()` etc.
                 feature_err(
-                    &self.tcx().sess.parse_sess,
+                    &self.tcx().sess,
                     sym::unboxed_closures,
                     span,
                     "parenthetical notation is only stable when used with `Fn`-family traits",
@@ -75,7 +75,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         if trait_segment.args().parenthesized != hir::GenericArgsParentheses::ParenSugar {
             // For now, require that parenthetical notation be used only with `Fn()` etc.
             let mut err = feature_err(
-                &sess.parse_sess,
+                sess,
                 sym::unboxed_closures,
                 span,
                 "the precise format of `Fn`-family traits' type parameters is subject to change",

compiler/rustc_hir_analysis/src/check/check.rs

@@ -996,7 +996,7 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>)
 
     if adt.is_union() && !tcx.features().transparent_unions {
         feature_err(
-            &tcx.sess.parse_sess,
+            &tcx.sess,
             sym::transparent_unions,
             tcx.def_span(adt.did()),
             "transparent unions are unstable",
@@ -1128,7 +1128,7 @@ fn check_enum(tcx: TyCtxt<'_>, def_id: LocalDefId) {
     if repr_type_ty == tcx.types.i128 || repr_type_ty == tcx.types.u128 {
         if !tcx.features().repr128 {
             feature_err(
-                &tcx.sess.parse_sess,
+                &tcx.sess,
                 sym::repr128,
                 tcx.def_span(def_id),
                 "repr with 128-bit type is unstable",

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -293,7 +293,7 @@ fn default_body_is_unstable(
 
     rustc_session::parse::add_feature_diagnostics_for_issue(
         &mut err,
-        &tcx.sess.parse_sess,
+        &tcx.sess,
         feature,
         rustc_feature::GateIssue::Library(issue),
         false,

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1591,7 +1591,7 @@ fn check_method_receiver<'tcx>(
             return Err(if receiver_is_valid(wfcx, span, receiver_ty, self_ty, true) {
                 // Report error; would have worked with `arbitrary_self_types`.
                 feature_err(
-                    &tcx.sess.parse_sess,
+                    &tcx.sess,
                     sym::arbitrary_self_types,
                     span,
                     format!(

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -1189,12 +1189,13 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                         && !self.tcx.asyncness(lifetime_ref.hir_id.owner.def_id).is_async()
                         && !self.tcx.features().anonymous_lifetime_in_impl_trait
                     {
-                        let mut diag = rustc_session::parse::feature_err(
-                            &self.tcx.sess.parse_sess,
-                            sym::anonymous_lifetime_in_impl_trait,
-                            lifetime_ref.ident.span,
-                            "anonymous lifetimes in `impl Trait` are unstable",
-                        );
+                        let mut diag: rustc_errors::DiagnosticBuilder<'_> =
+                            rustc_session::parse::feature_err(
+                                &self.tcx.sess,
+                                sym::anonymous_lifetime_in_impl_trait,
+                                lifetime_ref.ident.span,
+                                "anonymous lifetimes in `impl Trait` are unstable",
+                            );
 
                         if let Some(generics) =
                             self.tcx.hir().get_generics(lifetime_ref.hir_id.owner.def_id)

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -639,7 +639,7 @@ fn check_feature_inherent_assoc_ty(tcx: TyCtxt<'_>, span: Span) {
         use rustc_session::parse::feature_err;
         use rustc_span::symbol::sym;
         feature_err(
-            &tcx.sess.parse_sess,
+            &tcx.sess,
             sym::inherent_associated_types,
             span,
             "inherent associated types are unstable",

compiler/rustc_hir_analysis/src/lib.rs

@@ -134,13 +134,8 @@ fn require_c_abi_if_c_variadic(tcx: TyCtxt<'_>, decl: &hir::FnDecl<'_>, abi: Abi
         // Using this ABI would be ok, if the feature for additional ABI support was enabled.
         // Return CONVENTIONS_STABLE, because we want the other error to look the same.
         (false, true) => {
-            feature_err(
-                &tcx.sess.parse_sess,
-                sym::extended_varargs_abi_support,
-                span,
-                UNSTABLE_EXPLAIN,
-            )
-            .emit();
+            feature_err(&tcx.sess, sym::extended_varargs_abi_support, span, UNSTABLE_EXPLAIN)
+                .emit();
             CONVENTIONS_STABLE
         }