Rollup merge of #141936 - WaffleLapkin:report-in-deps-decoupling, r=oli-obk

Decouple "reporting in deps" from `FutureIncompatibilityReason`

The reason should just be it -- the reason. It never felt right to me that it was also responsible for whatever we include the warning in cargo's reports.

It gets especially unruly if you want to add non-`FutureReleaseError*` warnings which are included in the reports.

I just added a field to `FutureIncompatibleInfo` to control whatever the diagnostic is included in the cargo's reports.

4 files changed, 67 insertions, 82 deletions

diff --git a/compiler/rustc_lint/src/levels.rs b/compiler/rustc_lint/src/levels.rs
index 00775647ac6..c52dbd892bf 100644
--- a/compiler/rustc_lint/src/levels.rs
+++ b/compiler/rustc_lint/src/levels.rs
@@ -126,7 +126,7 @@ fn lints_that_dont_need_to_run(tcx: TyCtxt<'_>, (): ()) -> UnordSet<LintId> {
         .filter(|lint| {
             // Lints that show up in future-compat reports must always be run.
             let has_future_breakage =
-                lint.future_incompatible.is_some_and(|fut| fut.reason.has_future_breakage());
+                lint.future_incompatible.is_some_and(|fut| fut.report_in_deps);
             !has_future_breakage && !lint.eval_always
         })
         .filter(|lint| {
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 7c7ba85d484..1b14157c5f0 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -178,8 +178,9 @@ declare_lint! {
     Warn,
     "applying forbid to lint-groups",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #81670 <https://github.com/rust-lang/rust/issues/81670>",
+        report_in_deps: true,
     };
 }
 
@@ -214,7 +215,7 @@ declare_lint! {
     Deny,
     "ill-formed attribute inputs that were previously accepted and used in practice",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #57571 <https://github.com/rust-lang/rust/issues/57571>",
     };
     crate_level_only
@@ -251,8 +252,9 @@ declare_lint! {
     Deny,
     "conflicts between `#[repr(..)]` hints that were previously accepted and used in practice",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #68585 <https://github.com/rust-lang/rust/issues/68585>",
+        report_in_deps: true,
     };
 }
 
@@ -1240,8 +1242,9 @@ declare_lint! {
     Deny,
     "detect public re-exports of private extern crates",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #127909 <https://github.com/rust-lang/rust/issues/127909>",
+        report_in_deps: true,
     };
 }
 
@@ -1270,8 +1273,9 @@ declare_lint! {
     Deny,
     "type parameter default erroneously allowed in invalid location",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #36887 <https://github.com/rust-lang/rust/issues/36887>",
+        report_in_deps: true,
     };
 }
 
@@ -1409,7 +1413,7 @@ declare_lint! {
     Deny,
     "patterns in functions without body were erroneously allowed",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #35203 <https://github.com/rust-lang/rust/issues/35203>",
     };
 }
@@ -1453,8 +1457,9 @@ declare_lint! {
     Deny,
     "detects missing fragment specifiers in unused `macro_rules!` patterns",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #40107 <https://github.com/rust-lang/rust/issues/40107>",
+        report_in_deps: true,
     };
 }
 
@@ -1495,7 +1500,7 @@ declare_lint! {
     Warn,
     "detects generic lifetime arguments in path segments with late bound lifetime parameters",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #42868 <https://github.com/rust-lang/rust/issues/42868>",
     };
 }
@@ -2122,8 +2127,9 @@ declare_lint! {
     Deny,
     "detects proc macro derives using inaccessible names from parent modules",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #83583 <https://github.com/rust-lang/rust/issues/83583>",
+        report_in_deps: true,
     };
 }
 
@@ -2225,7 +2231,7 @@ declare_lint! {
     "macro-expanded `macro_export` macros from the current crate \
      cannot be referred to by absolute paths",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #52234 <https://github.com/rust-lang/rust/issues/52234>",
     };
     crate_level_only
@@ -2346,7 +2352,7 @@ declare_lint! {
     Deny,
     "ambiguous associated items",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #57644 <https://github.com/rust-lang/rust/issues/57644>",
     };
 }
@@ -2362,8 +2368,9 @@ declare_lint! {
     Deny,
     "a feature gate that doesn't break dependent crates",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #64266 <https://github.com/rust-lang/rust/issues/64266>",
+        report_in_deps: true,
     };
 }
 
@@ -2674,7 +2681,7 @@ declare_lint! {
     Warn,
     "detects a generic constant is used in a type without a emitting a warning",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #76200 <https://github.com/rust-lang/rust/issues/76200>",
     };
 }
@@ -2733,7 +2740,7 @@ declare_lint! {
     Warn,
     "uninhabited static",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #74840 <https://github.com/rust-lang/rust/issues/74840>",
     };
 }
@@ -2866,7 +2873,7 @@ declare_lint! {
     Warn,
     "detect unsupported use of `Self` from outer item",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #124186 <https://github.com/rust-lang/rust/issues/124186>",
     };
 }
@@ -2912,8 +2919,9 @@ declare_lint! {
     Warn,
     "trailing semicolon in macro body used as expression",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #79813 <https://github.com/rust-lang/rust/issues/79813>",
+        report_in_deps: true,
     };
 }
 
@@ -2959,7 +2967,7 @@ declare_lint! {
     Warn,
     "detects derive helper attributes that are used before they are introduced",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #79202 <https://github.com/rust-lang/rust/issues/79202>",
     };
 }
@@ -3126,7 +3134,7 @@ declare_lint! {
     Warn,
     "transparent type contains an external ZST that is marked #[non_exhaustive] or contains private fields",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #78586 <https://github.com/rust-lang/rust/issues/78586>",
     };
 }
@@ -3177,7 +3185,7 @@ declare_lint! {
     Warn,
     "unstable syntax can change at any point in the future, causing a hard error!",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #65860 <https://github.com/rust-lang/rust/issues/65860>",
     };
 }
@@ -3685,8 +3693,9 @@ declare_lint! {
     Warn,
     "use of unsupported calling convention for function pointer",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #130260 <https://github.com/rust-lang/rust/issues/130260>",
+        report_in_deps: true,
     };
 }
 
@@ -4368,7 +4377,7 @@ declare_lint! {
     Warn,
     "detects certain glob imports that require reporting an ambiguity error",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #114095 <https://github.com/rust-lang/rust/issues/114095>",
     };
 }
@@ -4523,7 +4532,7 @@ declare_lint! {
     Deny,
     "elided lifetimes cannot be used in associated constants in impls",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #115010 <https://github.com/rust-lang/rust/issues/115010>",
     };
 }
@@ -4570,7 +4579,7 @@ declare_lint! {
     Warn,
     "detects certain macro bindings that should not be re-exported",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #120192 <https://github.com/rust-lang/rust/issues/120192>",
     };
 }
@@ -4635,7 +4644,7 @@ declare_lint! {
     Warn,
     "impl contains type parameters that are not covered",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #124559 <https://github.com/rust-lang/rust/issues/124559>",
     };
 }
@@ -4799,7 +4808,7 @@ declare_lint! {
     Warn,
     "detects out of scope calls to `macro_rules` in key-value attributes",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #124535 <https://github.com/rust-lang/rust/issues/124535>",
     };
 }
@@ -5040,8 +5049,9 @@ declare_lint! {
     Warn,
     "detects code relying on rustc's non-spec-compliant wasm C ABI",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #138762 <https://github.com/rust-lang/rust/issues/138762>",
+        report_in_deps: true,
     };
 }
 
@@ -5081,7 +5091,8 @@ declare_lint! {
     Warn,
     "detects code that could be affected by ABI issues on aarch64 softfloat targets",
     @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reason: FutureIncompatibilityReason::FutureReleaseError,
         reference: "issue #134375 <https://github.com/rust-lang/rust/issues/134375>",
+        report_in_deps: true,
     };
 }
diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index 6cbdc245d21..e19bf59e543 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -361,6 +361,18 @@ pub struct FutureIncompatibleInfo {
     /// Set to false for lints that already include a more detailed
     /// explanation.
     pub explain_reason: bool,
+    /// If set to `true`, this will make future incompatibility warnings show up in cargo's
+    /// reports.
+    ///
+    /// When a future incompatibility warning is first inroduced, set this to `false`
+    /// (or, rather, don't override the default). This allows crate developers an opportunity
+    /// to fix the warning before blasting all dependents with a warning they can't fix
+    /// (dependents have to wait for a new release of the affected crate to be published).
+    ///
+    /// After a lint has been in this state for a while, consider setting this to true, so it
+    /// warns for everyone. It is a good signal that it is ready if you can determine that all
+    /// or most affected crates on crates.io have been updated.
+    pub report_in_deps: bool,
 }
 
 /// The reason for future incompatibility
@@ -380,46 +392,24 @@ pub struct FutureIncompatibleInfo {
 pub enum FutureIncompatibilityReason {
     /// This will be an error in a future release for all editions
     ///
-    /// This will *not* show up in cargo's future breakage report.
-    /// The warning will hence only be seen in local crates, not in dependencies.
-    ///
     /// Choose this variant when you are first introducing a "future
     /// incompatible" warning that is intended to eventually be fixed in the
-    /// future. This allows crate developers an opportunity to fix the warning
-    /// before blasting all dependents with a warning they can't fix
-    /// (dependents have to wait for a new release of the affected crate to be
-    /// published).
-    ///
-    /// After a lint has been in this state for a while, consider graduating
-    /// it to [`FutureIncompatibilityReason::FutureReleaseErrorReportInDeps`].
-    FutureReleaseErrorDontReportInDeps,
-    /// This will be an error in a future release, and
-    /// Cargo should create a report even for dependencies
+    /// future.
     ///
-    /// This is the *only* reason that will make future incompatibility warnings show up in cargo's
-    /// reports. All other future incompatibility warnings are not visible when they occur in a
-    /// dependency.
-    ///
-    /// Choose this variant after the lint has been sitting in the
-    /// [`FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps`]
-    /// state for a while, and you feel like it is ready to graduate to
-    /// warning everyone. It is a good signal that it is ready if you can
-    /// determine that all or most affected crates on crates.io have been
-    /// updated.
+    /// After a lint has been in this state for a while and you feel like it is ready to graduate
+    /// to warning everyone, consider setting [`FutureIncompatibleInfo::report_in_deps`] to true.
+    /// (see it's documentation for more guidance)
     ///
     /// After some period of time, lints with this variant can be turned into
     /// hard errors (and the lint removed). Preferably when there is some
     /// confidence that the number of impacted projects is very small (few
     /// should have a broken dependency in their dependency tree).
-    ///
-    /// [`EditionAndFutureReleaseError`]: FutureIncompatibilityReason::EditionAndFutureReleaseError
-    FutureReleaseErrorReportInDeps,
+    FutureReleaseError,
     /// Code that changes meaning in some way in a
     /// future release.
     ///
     /// Choose this variant when the semantics of existing code is changing,
-    /// (as opposed to
-    /// [`FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps`],
+    /// (as opposed to [`FutureIncompatibilityReason::FutureReleaseError`],
     /// which is for when code is going to be rejected in the future).
     FutureReleaseSemanticsChange,
     /// Previously accepted code that will become an
@@ -454,13 +444,12 @@ pub enum FutureIncompatibilityReason {
     /// This will be an error in the provided edition *and* in a future
     /// release.
     ///
-    /// This variant a combination of [`FutureReleaseErrorDontReportInDeps`]
-    /// and [`EditionError`]. This is useful in rare cases when we
-    /// want to have "preview" of a breaking change in an edition, but do a
-    /// breaking change later on all editions anyway.
+    /// This variant a combination of [`FutureReleaseError`] and [`EditionError`].
+    /// This is useful in rare cases when we want to have "preview" of a breaking
+    /// change in an edition, but do a breaking change later on all editions anyway.
     ///
     /// [`EditionError`]: FutureIncompatibilityReason::EditionError
-    /// [`FutureReleaseErrorDontReportInDeps`]: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps
+    /// [`FutureReleaseError`]: FutureIncompatibilityReason::FutureReleaseError
     EditionAndFutureReleaseError(Edition),
     /// This will change meaning in the provided edition *and* in a future
     /// release.
@@ -478,7 +467,7 @@ pub enum FutureIncompatibilityReason {
     /// Choose this variant if the built-in text of the diagnostic of the
     /// other variants doesn't match your situation. This is behaviorally
     /// equivalent to
-    /// [`FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps`].
+    /// [`FutureIncompatibilityReason::FutureReleaseError`].
     Custom(&'static str),
 }
 
@@ -490,34 +479,20 @@ impl FutureIncompatibilityReason {
             | Self::EditionAndFutureReleaseError(e)
             | Self::EditionAndFutureReleaseSemanticsChange(e) => Some(e),
 
-            FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps
-            | FutureIncompatibilityReason::FutureReleaseErrorReportInDeps
+            FutureIncompatibilityReason::FutureReleaseError
             | FutureIncompatibilityReason::FutureReleaseSemanticsChange
             | FutureIncompatibilityReason::Custom(_) => None,
         }
     }
-
-    pub fn has_future_breakage(self) -> bool {
-        match self {
-            FutureIncompatibilityReason::FutureReleaseErrorReportInDeps => true,
-
-            FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps
-            | FutureIncompatibilityReason::FutureReleaseSemanticsChange
-            | FutureIncompatibilityReason::EditionError(_)
-            | FutureIncompatibilityReason::EditionSemanticsChange(_)
-            | FutureIncompatibilityReason::EditionAndFutureReleaseError(_)
-            | FutureIncompatibilityReason::EditionAndFutureReleaseSemanticsChange(_)
-            | FutureIncompatibilityReason::Custom(_) => false,
-        }
-    }
 }
 
 impl FutureIncompatibleInfo {
     pub const fn default_fields_for_macro() -> Self {
         FutureIncompatibleInfo {
             reference: "",
-            reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+            reason: FutureIncompatibilityReason::FutureReleaseError,
             explain_reason: true,
+            report_in_deps: false,
         }
     }
 }
diff --git a/compiler/rustc_middle/src/lint.rs b/compiler/rustc_middle/src/lint.rs
index d5a408fdfa6..341a735f88f 100644
--- a/compiler/rustc_middle/src/lint.rs
+++ b/compiler/rustc_middle/src/lint.rs
@@ -299,7 +299,7 @@ pub fn lint_level(
         let has_future_breakage = future_incompatible.map_or(
             // Default allow lints trigger too often for testing.
             sess.opts.unstable_opts.future_incompat_test && lint.default_level != Level::Allow,
-            |incompat| incompat.reason.has_future_breakage(),
+            |incompat| incompat.report_in_deps,
         );
 
         // Convert lint level to error level.
@@ -370,8 +370,7 @@ pub fn lint_level(
 
         if let Some(future_incompatible) = future_incompatible {
             let explanation = match future_incompatible.reason {
-                FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps
-                | FutureIncompatibilityReason::FutureReleaseErrorReportInDeps => {
+                FutureIncompatibilityReason::FutureReleaseError => {
                     "this was previously accepted by the compiler but is being phased out; \
                          it will become a hard error in a future release!"
                         .to_owned()