turn pointer_structural_match into a hard error

compiler/rustc_lint/src/lib.rs

@@ -544,6 +544,11 @@ fn register_builtins(store: &mut LintStore) {
         "converted into hard error, see RFC #3535 \
          <https://rust-lang.github.io/rfcs/3535-constants-in-patterns.html> for more information",
     );
+    store.register_removed(
+        "pointer_structural_match",
+        "converted into hard error, see RFC #3535 \
+         <https://rust-lang.github.io/rfcs/3535-constants-in-patterns.html> for more information",
+    );
 }
 
 fn register_internals(store: &mut LintStore) {

compiler/rustc_lint_defs/src/builtin.rs

@@ -74,7 +74,6 @@ declare_lint_pass! {
         ORDER_DEPENDENT_TRAIT_OBJECTS,
         OVERLAPPING_RANGE_ENDPOINTS,
         PATTERNS_IN_FNS_WITHOUT_BODY,
-        POINTER_STRUCTURAL_MATCH,
         PRIVATE_BOUNDS,
         PRIVATE_INTERFACES,
         PROC_MACRO_BACK_COMPAT,
@@ -2371,45 +2370,6 @@ declare_lint! {
     report_in_external_macro
 }
 
-declare_lint! {
-    /// The `pointer_structural_match` lint detects pointers used in patterns whose behaviour
-    /// cannot be relied upon across compiler versions and optimization levels.
-    ///
-    /// ### Example
-    ///
-    /// ```rust,compile_fail
-    /// #![deny(pointer_structural_match)]
-    /// fn foo(a: usize, b: usize) -> usize { a + b }
-    /// const FOO: fn(usize, usize) -> usize = foo;
-    /// fn main() {
-    ///     match FOO {
-    ///         FOO => {},
-    ///         _ => {},
-    ///     }
-    /// }
-    /// ```
-    ///
-    /// {{produces}}
-    ///
-    /// ### Explanation
-    ///
-    /// Previous versions of Rust allowed function pointers and all raw pointers in patterns.
-    /// While these work in many cases as expected by users, it is possible that due to
-    /// optimizations pointers are "not equal to themselves" or pointers to different functions
-    /// compare as equal during runtime. This is because LLVM optimizations can deduplicate
-    /// functions if their bodies are the same, thus also making pointers to these functions point
-    /// to the same location. Additionally functions may get duplicated if they are instantiated
-    /// in different crates and not deduplicated again via LTO. Pointer identity for memory
-    /// created by `const` is similarly unreliable.
-    pub POINTER_STRUCTURAL_MATCH,
-    Warn,
-    "pointers are not structural-match",
-    @future_incompatible = FutureIncompatibleInfo {
-        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
-        reference: "issue #120362 <https://github.com/rust-lang/rust/issues/120362>",
-    };
-}
-
 declare_lint! {
     /// The `ambiguous_associated_items` lint detects ambiguity between
     /// [associated items] and [enum variants].

compiler/rustc_mir_build/src/errors.rs

@@ -788,9 +788,12 @@ pub struct NaNPattern {
     pub span: Span,
 }
 
-#[derive(LintDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(mir_build_pointer_pattern)]
-pub struct PointerPattern;
+pub struct PointerPattern {
+    #[primary_span]
+    pub span: Span,
+}
 
 #[derive(Diagnostic)]
 #[diag(mir_build_non_empty_never_pattern)]

compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs

@@ -6,7 +6,6 @@ use rustc_infer::traits::Obligation;
 use rustc_middle::mir;
 use rustc_middle::thir::{FieldPat, Pat, PatKind};
 use rustc_middle::ty::{self, Ty, TyCtxt, ValTree};
-use rustc_session::lint;
 use rustc_span::{ErrorGuaranteed, Span};
 use rustc_target::abi::{FieldIdx, VariantIdx};
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
@@ -189,12 +188,9 @@ impl<'tcx> ConstToPat<'tcx> {
             } else if !have_valtree {
                 // The only way valtree construction can fail without the structural match
                 // checker finding a violation is if there is a pointer somewhere.
-                self.tcx().emit_node_span_lint(
-                    lint::builtin::POINTER_STRUCTURAL_MATCH,
-                    self.id,
-                    self.span,
-                    PointerPattern,
-                );
+                let e = self.tcx().dcx().emit_err(PointerPattern { span: self.span });
+                let kind = PatKind::Error(e);
+                return Box::new(Pat { span: self.span, ty: cv.ty(), kind });
             }
 
             // Always check for `PartialEq` if we had no other errors yet.

tests/ui/closures/2229_closure_analysis/match/match-edge-cases_1.rs

@@ -2,8 +2,7 @@
 //@ edition:2021
 
 const PATTERN_REF: &str = "Hello World";
-const NUMBER: i32 = 30;
-const NUMBER_POINTER: *const i32 = &NUMBER;
+const NUMBER_POINTER: *const i32 = 30 as *const i32;
 
 pub fn edge_case_ref(event: &str) {
     let _ = || {
@@ -26,8 +25,7 @@ pub fn edge_case_str(event: String) {
 pub fn edge_case_raw_ptr(event: *const i32) {
     let _ = || {
         match event {
-            NUMBER_POINTER => (), //~WARN behave unpredictably
-            //~| previously accepted
+            NUMBER_POINTER => (),
             _ => (),
         };
     };

tests/ui/consts/const_in_pattern/issue-34784-match-on-non-int-raw-ptr.rs

@@ -1,4 +1,3 @@
-#![deny(pointer_structural_match)]
 #![allow(dead_code)]
 
 const C: *const u8 = &0;
@@ -8,15 +7,13 @@ const C_INNER: (*const u8, u8) = (C, 0);
 fn foo(x: *const u8) {
     match x {
         C => {} //~ERROR: behave unpredictably
-        //~| previously accepted
         _ => {}
     }
 }
 
 fn foo2(x: *const u8) {
     match (x, 1) {
         C_INNER => {} //~ERROR: behave unpredictably
-        //~| previously accepted
         _ => {}
     }
 }
@@ -28,13 +25,11 @@ const STR: *const str = "abcd";
 fn main() {
     match D {
         D => {} //~ERROR: behave unpredictably
-        //~| previously accepted
         _ => {}
     }
 
     match STR {
         STR => {} //~ERROR: behave unpredictably
-        //~| previously accepted
         _ => {}
     }
 }

tests/ui/consts/const_in_pattern/issue-34784-match-on-non-int-raw-ptr.stderr

@@ -1,103 +1,26 @@
 error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:10:9
+  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:9:9
    |
 LL |         C => {}
    |         ^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-note: the lint level is defined here
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:1:9
-   |
-LL | #![deny(pointer_structural_match)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:18:9
+  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:16:9
    |
 LL |         C_INNER => {}
    |         ^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
 
 error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:30:9
+  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:27:9
    |
 LL |         D => {}
    |         ^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
 
 error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:36:9
+  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:32:9
    |
 LL |         STR => {}
    |         ^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
 
 error: aborting due to 4 previous errors
 
-Future incompatibility report: Future breakage diagnostic:
-error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:10:9
-   |
-LL |         C => {}
-   |         ^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-note: the lint level is defined here
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:1:9
-   |
-LL | #![deny(pointer_structural_match)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
-
-Future breakage diagnostic:
-error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:18:9
-   |
-LL |         C_INNER => {}
-   |         ^^^^^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-note: the lint level is defined here
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:1:9
-   |
-LL | #![deny(pointer_structural_match)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
-
-Future breakage diagnostic:
-error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:30:9
-   |
-LL |         D => {}
-   |         ^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-note: the lint level is defined here
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:1:9
-   |
-LL | #![deny(pointer_structural_match)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
-
-Future breakage diagnostic:
-error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:36:9
-   |
-LL |         STR => {}
-   |         ^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-note: the lint level is defined here
-  --> $DIR/issue-34784-match-on-non-int-raw-ptr.rs:1:9
-   |
-LL | #![deny(pointer_structural_match)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
-

tests/ui/consts/const_in_pattern/issue-44333.rs

@@ -1,7 +1,3 @@
-//@ run-pass
-
-#![warn(pointer_structural_match)]
-
 type Func = fn(usize, usize) -> usize;
 
 fn foo(a: usize, b: usize) -> usize { a + b }
@@ -16,10 +12,8 @@ const BAR: Func = bar;
 
 fn main() {
     match test(std::env::consts::ARCH.len()) {
-        FOO => println!("foo"), //~ WARN behave unpredictably
-        //~^ WARN will become a hard error
-        BAR => println!("bar"), //~ WARN behave unpredictably
-        //~^ WARN will become a hard error
+        FOO => println!("foo"), //~ ERROR behave unpredictably
+        BAR => println!("bar"), //~ ERROR behave unpredictably
         _ => unreachable!(),
     }
 }

tests/ui/consts/const_in_pattern/issue-44333.stderr

@@ -1,55 +1,14 @@
-warning: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-44333.rs:19:9
+error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
+  --> $DIR/issue-44333.rs:15:9
    |
 LL |         FOO => println!("foo"),
    |         ^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-note: the lint level is defined here
-  --> $DIR/issue-44333.rs:3:9
-   |
-LL | #![warn(pointer_structural_match)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
 
-warning: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-44333.rs:21:9
+error: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
+  --> $DIR/issue-44333.rs:16:9
    |
 LL |         BAR => println!("bar"),
    |         ^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-
-warning: 2 warnings emitted
 
-Future incompatibility report: Future breakage diagnostic:
-warning: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-44333.rs:19:9
-   |
-LL |         FOO => println!("foo"),
-   |         ^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-note: the lint level is defined here
-  --> $DIR/issue-44333.rs:3:9
-   |
-LL | #![warn(pointer_structural_match)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
-
-Future breakage diagnostic:
-warning: function pointers and raw pointers not derived from integers in patterns behave unpredictably and should not be relied upon. See https://github.com/rust-lang/rust/issues/70861 for details.
-  --> $DIR/issue-44333.rs:21:9
-   |
-LL |         BAR => println!("bar"),
-   |         ^^^
-   |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
-note: the lint level is defined here
-  --> $DIR/issue-44333.rs:3:9
-   |
-LL | #![warn(pointer_structural_match)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
+error: aborting due to 2 previous errors