Rollup merge of #86330 - rylev:update-fcw-handling, r=nikomatsakis

Change how edition based future compatibility warnings are handled

This fixes #85894 by updating how future compatibility lints work. This makes it more apparent that future compatibility warnings can happen for several different reasons.

For now `FutureCompatibilityReasons` are limited to three reasons, but we can easily add more.

This also updates the generated warning for FCW's that signal code that will error in a future edition. This makes the diagnostics between FCWs at edition boundaries more distinct from those not happening at an edition boundary.

r? ``@m-ou-se``

Author: JohnTitor

compiler/rustc_lint/src/array_into_iter.rs

@@ -3,7 +3,8 @@ use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_middle::ty;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment};
-use rustc_session::lint::FutureBreakage;
+use rustc_session::lint::FutureIncompatibilityReason;
+use rustc_span::edition::Edition;
 use rustc_span::symbol::sym;
 
 declare_lint! {
@@ -37,10 +38,7 @@ declare_lint! {
     "detects calling `into_iter` on arrays",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #66145 <https://github.com/rust-lang/rust/issues/66145>",
-        edition: None,
-        future_breakage: Some(FutureBreakage {
-            date: None
-        })
+        reason: FutureIncompatibilityReason::EditionSemanticsChange(Edition::Edition2021),
     };
 }
 

compiler/rustc_lint/src/builtin.rs

@@ -47,6 +47,7 @@ use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::subst::{GenericArgKind, Subst};
 use rustc_middle::ty::Instance;
 use rustc_middle::ty::{self, layout::LayoutError, Ty, TyCtxt};
+use rustc_session::lint::FutureIncompatibilityReason;
 use rustc_session::Session;
 use rustc_span::edition::Edition;
 use rustc_span::source_map::Spanned;
@@ -874,7 +875,7 @@ declare_lint! {
     "detects anonymous parameters",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #41686 <https://github.com/rust-lang/rust/issues/41686>",
-        edition: Some(Edition::Edition2018),
+        reason: FutureIncompatibilityReason::EditionError(Edition::Edition2018),
     };
 }
 
@@ -1663,7 +1664,7 @@ declare_lint! {
     "`...` range patterns are deprecated",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #80165 <https://github.com/rust-lang/rust/issues/80165>",
-        edition: Some(Edition::Edition2021),
+        reason: FutureIncompatibilityReason::EditionError(Edition::Edition2021),
     };
 }
 
@@ -1891,7 +1892,7 @@ declare_lint! {
     "detects edition keywords being used as an identifier",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #49716 <https://github.com/rust-lang/rust/issues/49716>",
-        edition: Some(Edition::Edition2018),
+        reason: FutureIncompatibilityReason::EditionError(Edition::Edition2018),
     };
 }