Auto merge of rust-lang#71441 - RalfJung:beta-const-validation-fix, r=Mark-Simulacrum

[beta] fix failing const validation

This is the **beta branch fix** for rust-lang#71353, by reverting rust-lang#70566.

r? @oli-obk
Not sure if there is any extra process for the beta part. This is not a backport; we intend to "properly" fix this on master but for beta a revert is faster and less risky.

Author: bors

src/librustc_mir/transform/const_prop.rs

@@ -604,6 +604,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
+        // FIXME we need to revisit this for #67176
+        if rvalue.needs_subst() {
+            return None;
+        }
+
         // Perform any special handling for specific Rvalue types.
         // Generally, checks here fall into one of two categories:
         //   1. Additional checking to provide useful lints to the user
@@ -644,11 +649,6 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             _ => {}
         }
 
-        // FIXME we need to revisit this for #67176
-        if rvalue.needs_subst() {
-            return None;
-        }
-
         self.use_ecx(|this| {
             trace!("calling eval_rvalue_into_place(rvalue = {:?}, place = {:?})", rvalue, place);
             this.ecx.eval_rvalue_into_place(rvalue, place)?;

src/test/ui/consts/const-eval/ice-generic-assoc-const.rs

@@ -1,4 +1,5 @@
-// check-pass
+// build-pass (tests post-monomorphisation failure)
+#![crate_type = "lib"]
 
 pub trait Nullable {
     const NULL: Self;
@@ -13,6 +14,3 @@ impl<T> Nullable for *const T {
         *self == Self::NULL
     }
 }
-
-fn main() {
-}

src/test/ui/lint/lint-exceeding-bitshifts.noopt.stderr

@@ -1,152 +1,146 @@
-warning: this arithmetic operation will overflow
-  --> $DIR/lint-exceeding-bitshifts.rs:18:20
+error: this arithmetic operation will overflow
+  --> $DIR/lint-exceeding-bitshifts.rs:22:13
    |
-LL |     const N: i32 = T::N << 42;
-   |                    ^^^^^^^^^^ attempt to shift left with overflow
+LL |     let _ = x << 42;
+   |             ^^^^^^^ attempt to shift left with overflow
    |
 note: the lint level is defined here
   --> $DIR/lint-exceeding-bitshifts.rs:9:9
    |
-LL | #![warn(arithmetic_overflow, const_err)]
+LL | #![deny(arithmetic_overflow, const_err)]
    |         ^^^^^^^^^^^^^^^^^^^
 
-warning: this arithmetic operation will overflow
-  --> $DIR/lint-exceeding-bitshifts.rs:22:13
-   |
-LL |     let _ = x << 42;
-   |             ^^^^^^^ attempt to shift left with overflow
-
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:27:15
    |
 LL |       let n = 1u8 << 8;
    |               ^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:29:15
    |
 LL |       let n = 1u16 << 16;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:31:15
    |
 LL |       let n = 1u32 << 32;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:33:15
    |
 LL |       let n = 1u64 << 64;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:35:15
    |
 LL |       let n = 1i8 << 8;
    |               ^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:37:15
    |
 LL |       let n = 1i16 << 16;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:39:15
    |
 LL |       let n = 1i32 << 32;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:41:15
    |
 LL |       let n = 1i64 << 64;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:44:15
    |
 LL |       let n = 1u8 >> 8;
    |               ^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:46:15
    |
 LL |       let n = 1u16 >> 16;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:48:15
    |
 LL |       let n = 1u32 >> 32;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:50:15
    |
 LL |       let n = 1u64 >> 64;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:52:15
    |
 LL |       let n = 1i8 >> 8;
    |               ^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:54:15
    |
 LL |       let n = 1i16 >> 16;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:56:15
    |
 LL |       let n = 1i32 >> 32;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:58:15
    |
 LL |       let n = 1i64 >> 64;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:62:15
    |
 LL |       let n = n << 8;
    |               ^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:64:15
    |
 LL |       let n = 1u8 << -8;
    |               ^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:69:15
    |
 LL |       let n = 1u8 << (4+4);
    |               ^^^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:71:15
    |
 LL |       let n = 1i64 >> [64][0];
    |               ^^^^^^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:77:15
    |
 LL |       let n = 1_isize << BITS;
    |               ^^^^^^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:78:15
    |
 LL |       let n = 1_usize << BITS;
    |               ^^^^^^^^^^^^^^^ attempt to shift left with overflow
 
-warning: 24 warnings emitted
+error: aborting due to 23 previous errors
 

src/test/ui/lint/lint-exceeding-bitshifts.opt.stderr

@@ -1,152 +1,146 @@
-warning: this arithmetic operation will overflow
-  --> $DIR/lint-exceeding-bitshifts.rs:18:20
+error: this arithmetic operation will overflow
+  --> $DIR/lint-exceeding-bitshifts.rs:22:13
    |
-LL |     const N: i32 = T::N << 42;
-   |                    ^^^^^^^^^^ attempt to shift left with overflow
+LL |     let _ = x << 42;
+   |             ^^^^^^^ attempt to shift left with overflow
    |
 note: the lint level is defined here
   --> $DIR/lint-exceeding-bitshifts.rs:9:9
    |
-LL | #![warn(arithmetic_overflow, const_err)]
+LL | #![deny(arithmetic_overflow, const_err)]
    |         ^^^^^^^^^^^^^^^^^^^
 
-warning: this arithmetic operation will overflow
-  --> $DIR/lint-exceeding-bitshifts.rs:22:13
-   |
-LL |     let _ = x << 42;
-   |             ^^^^^^^ attempt to shift left with overflow
-
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:27:15
    |
 LL |       let n = 1u8 << 8;
    |               ^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:29:15
    |
 LL |       let n = 1u16 << 16;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:31:15
    |
 LL |       let n = 1u32 << 32;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:33:15
    |
 LL |       let n = 1u64 << 64;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:35:15
    |
 LL |       let n = 1i8 << 8;
    |               ^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:37:15
    |
 LL |       let n = 1i16 << 16;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:39:15
    |
 LL |       let n = 1i32 << 32;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:41:15
    |
 LL |       let n = 1i64 << 64;
    |               ^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:44:15
    |
 LL |       let n = 1u8 >> 8;
    |               ^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:46:15
    |
 LL |       let n = 1u16 >> 16;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:48:15
    |
 LL |       let n = 1u32 >> 32;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:50:15
    |
 LL |       let n = 1u64 >> 64;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:52:15
    |
 LL |       let n = 1i8 >> 8;
    |               ^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:54:15
    |
 LL |       let n = 1i16 >> 16;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:56:15
    |
 LL |       let n = 1i32 >> 32;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:58:15
    |
 LL |       let n = 1i64 >> 64;
    |               ^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:62:15
    |
 LL |       let n = n << 8;
    |               ^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:64:15
    |
 LL |       let n = 1u8 << -8;
    |               ^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:69:15
    |
 LL |       let n = 1u8 << (4+4);
    |               ^^^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:71:15
    |
 LL |       let n = 1i64 >> [64][0];
    |               ^^^^^^^^^^^^^^^ attempt to shift right with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:77:15
    |
 LL |       let n = 1_isize << BITS;
    |               ^^^^^^^^^^^^^^^ attempt to shift left with overflow
 
-warning: this arithmetic operation will overflow
+error: this arithmetic operation will overflow
   --> $DIR/lint-exceeding-bitshifts.rs:78:15
    |
 LL |       let n = 1_usize << BITS;
    |               ^^^^^^^^^^^^^^^ attempt to shift left with overflow
 
-warning: 24 warnings emitted
+error: aborting due to 23 previous errors