avoid promoting division, modulo and indexing operations that could fail

16 files changed, 278 insertions, 278 deletions

diff --git a/src/test/mir-opt/const_allocation2.main.ConstProp.after.32bit.mir b/src/test/mir-opt/const_allocation2.main.ConstProp.after.32bit.mir
index d2e764f856f..9fe3234f6ae 100644
--- a/src/test/mir-opt/const_allocation2.main.ConstProp.after.32bit.mir
+++ b/src/test/mir-opt/const_allocation2.main.ConstProp.after.32bit.mir
@@ -24,41 +24,41 @@ fn main() -> () {
 }
 
 alloc0 (static: FOO, size: 8, align: 4) {
-    ╾─alloc27─╼ 03 00 00 00                         │ ╾──╼....
+    ╾─alloc31─╼ 03 00 00 00                         │ ╾──╼....
 }
 
-alloc27 (size: 48, align: 4) {
-    0x00 │ 00 00 00 00 __ __ __ __ ╾─alloc12─╼ 00 00 00 00 │ ....░░░░╾──╼....
-    0x10 │ 00 00 00 00 __ __ __ __ ╾─alloc17─╼ 02 00 00 00 │ ....░░░░╾──╼....
-    0x20 │ 01 00 00 00 2a 00 00 00 ╾─alloc25─╼ 03 00 00 00 │ ....*...╾──╼....
+alloc31 (size: 48, align: 4) {
+    0x00 │ 00 00 00 00 __ __ __ __ ╾─alloc8──╼ 00 00 00 00 │ ....░░░░╾──╼....
+    0x10 │ 00 00 00 00 __ __ __ __ ╾─alloc14─╼ 02 00 00 00 │ ....░░░░╾──╼....
+    0x20 │ 01 00 00 00 2a 00 00 00 ╾─alloc29─╼ 03 00 00 00 │ ....*...╾──╼....
 }
 
-alloc12 (size: 0, align: 4) {}
+alloc8 (size: 0, align: 4) {}
 
-alloc17 (size: 8, align: 4) {
-    ╾─alloc15─╼ ╾─alloc16─╼                         │ ╾──╼╾──╼
+alloc14 (size: 8, align: 4) {
+    ╾─alloc12─╼ ╾─alloc13─╼                         │ ╾──╼╾──╼
 }
 
-alloc15 (size: 1, align: 1) {
+alloc12 (size: 1, align: 1) {
     05                                              │ .
 }
 
-alloc16 (size: 1, align: 1) {
+alloc13 (size: 1, align: 1) {
     06                                              │ .
 }
 
-alloc25 (size: 12, align: 4) {
-    ╾─a21+0x3─╼ ╾─alloc22─╼ ╾─a24+0x2─╼             │ ╾──╼╾──╼╾──╼
+alloc29 (size: 12, align: 4) {
+    ╾─a21+0x3─╼ ╾─alloc23─╼ ╾─a28+0x2─╼             │ ╾──╼╾──╼╾──╼
 }
 
 alloc21 (size: 4, align: 1) {
     2a 45 15 6f                                     │ *E.o
 }
 
-alloc22 (size: 1, align: 1) {
+alloc23 (size: 1, align: 1) {
     2a                                              │ *
 }
 
-alloc24 (size: 4, align: 1) {
+alloc28 (size: 4, align: 1) {
     2a 45 15 6f                                     │ *E.o
 }
diff --git a/src/test/mir-opt/const_allocation2.main.ConstProp.after.64bit.mir b/src/test/mir-opt/const_allocation2.main.ConstProp.after.64bit.mir
index 00bf91f90bf..3039f8ffab7 100644
--- a/src/test/mir-opt/const_allocation2.main.ConstProp.after.64bit.mir
+++ b/src/test/mir-opt/const_allocation2.main.ConstProp.after.64bit.mir
@@ -24,44 +24,44 @@ fn main() -> () {
 }
 
 alloc0 (static: FOO, size: 16, align: 8) {
-    ╾───────alloc27───────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
+    ╾───────alloc31───────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
 }
 
-alloc27 (size: 72, align: 8) {
-    0x00 │ 00 00 00 00 __ __ __ __ ╾───────alloc12───────╼ │ ....░░░░╾──────╼
+alloc31 (size: 72, align: 8) {
+    0x00 │ 00 00 00 00 __ __ __ __ ╾───────alloc8────────╼ │ ....░░░░╾──────╼
     0x10 │ 00 00 00 00 00 00 00 00 00 00 00 00 __ __ __ __ │ ............░░░░
-    0x20 │ ╾───────alloc17───────╼ 02 00 00 00 00 00 00 00 │ ╾──────╼........
-    0x30 │ 01 00 00 00 2a 00 00 00 ╾───────alloc25───────╼ │ ....*...╾──────╼
+    0x20 │ ╾───────alloc14───────╼ 02 00 00 00 00 00 00 00 │ ╾──────╼........
+    0x30 │ 01 00 00 00 2a 00 00 00 ╾───────alloc29───────╼ │ ....*...╾──────╼
     0x40 │ 03 00 00 00 00 00 00 00                         │ ........
 }
 
-alloc12 (size: 0, align: 8) {}
+alloc8 (size: 0, align: 8) {}
 
-alloc17 (size: 16, align: 8) {
-    ╾───────alloc15───────╼ ╾───────alloc16───────╼ │ ╾──────╼╾──────╼
+alloc14 (size: 16, align: 8) {
+    ╾───────alloc12───────╼ ╾───────alloc13───────╼ │ ╾──────╼╾──────╼
 }
 
-alloc15 (size: 1, align: 1) {
+alloc12 (size: 1, align: 1) {
     05                                              │ .
 }
 
-alloc16 (size: 1, align: 1) {
+alloc13 (size: 1, align: 1) {
     06                                              │ .
 }
 
-alloc25 (size: 24, align: 8) {
-    0x00 │ ╾─────alloc21+0x3─────╼ ╾───────alloc22───────╼ │ ╾──────╼╾──────╼
-    0x10 │ ╾─────alloc24+0x2─────╼                         │ ╾──────╼
+alloc29 (size: 24, align: 8) {
+    0x00 │ ╾─────alloc21+0x3─────╼ ╾───────alloc23───────╼ │ ╾──────╼╾──────╼
+    0x10 │ ╾─────alloc28+0x2─────╼                         │ ╾──────╼
 }
 
 alloc21 (size: 4, align: 1) {
     2a 45 15 6f                                     │ *E.o
 }
 
-alloc22 (size: 1, align: 1) {
+alloc23 (size: 1, align: 1) {
     2a                                              │ *
 }
 
-alloc24 (size: 4, align: 1) {
+alloc28 (size: 4, align: 1) {
     2a 45 15 6f                                     │ *E.o
 }
diff --git a/src/test/mir-opt/const_allocation3.main.ConstProp.after.32bit.mir b/src/test/mir-opt/const_allocation3.main.ConstProp.after.32bit.mir
index 519002da392..cf7d82ef15e 100644
--- a/src/test/mir-opt/const_allocation3.main.ConstProp.after.32bit.mir
+++ b/src/test/mir-opt/const_allocation3.main.ConstProp.after.32bit.mir
@@ -24,30 +24,30 @@ fn main() -> () {
 }
 
 alloc0 (static: FOO, size: 4, align: 4) {
-    ╾─alloc10─╼                                     │ ╾──╼
+    ╾─alloc11─╼                                     │ ╾──╼
 }
 
-alloc10 (size: 168, align: 1) {
+alloc11 (size: 168, align: 1) {
     0x00 │ ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab │ ................
-    0x10 │ ab ab ab ab ab ab ab ab ab ab ab ab ╾─alloc5──╼ │ ............╾──╼
+    0x10 │ ab ab ab ab ab ab ab ab ab ab ab ab ╾─alloc4──╼ │ ............╾──╼
     0x20 │ 01 ef cd ab 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x30 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x40 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x50 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x60 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x70 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
-    0x80 │ 00 00 00 00 00 00 00 00 00 00 ╾─alloc7──╼ 00 00 │ ..........╾──╼..
-    0x90 │ ╾─a8+0x63─╼ 00 00 00 00 00 00 00 00 00 00 00 00 │ ╾──╼............
+    0x80 │ 00 00 00 00 00 00 00 00 00 00 ╾─alloc6──╼ 00 00 │ ..........╾──╼..
+    0x90 │ ╾─a9+0x63─╼ 00 00 00 00 00 00 00 00 00 00 00 00 │ ╾──╼............
     0xa0 │ 00 00 00 00 00 00 00 00                         │ ........
 }
 
-alloc5 (size: 4, align: 4) {
+alloc4 (size: 4, align: 4) {
     2a 00 00 00                                     │ *...
 }
 
-alloc7 (fn: main)
+alloc6 (fn: main)
 
-alloc8 (size: 100, align: 1) {
+alloc9 (size: 100, align: 1) {
     0x00 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x10 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x20 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
diff --git a/src/test/mir-opt/const_allocation3.main.ConstProp.after.64bit.mir b/src/test/mir-opt/const_allocation3.main.ConstProp.after.64bit.mir
index 73c4288c32e..f2227c40fcb 100644
--- a/src/test/mir-opt/const_allocation3.main.ConstProp.after.64bit.mir
+++ b/src/test/mir-opt/const_allocation3.main.ConstProp.after.64bit.mir
@@ -24,12 +24,12 @@ fn main() -> () {
 }
 
 alloc0 (static: FOO, size: 8, align: 8) {
-    ╾───────alloc10───────╼                         │ ╾──────╼
+    ╾───────alloc11───────╼                         │ ╾──────╼
 }
 
-alloc10 (size: 180, align: 1) {
+alloc11 (size: 180, align: 1) {
     0x00 │ ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab │ ................
-    0x10 │ ab ab ab ab ab ab ab ab ab ab ab ab ╾──alloc5── │ ............╾───
+    0x10 │ ab ab ab ab ab ab ab ab ab ab ab ab ╾──alloc4── │ ............╾───
     0x20 │ ──────────╼ 01 ef cd ab 00 00 00 00 00 00 00 00 │ ───╼............
     0x30 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x40 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
@@ -37,18 +37,18 @@ alloc10 (size: 180, align: 1) {
     0x60 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x70 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x80 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ╾──── │ ..............╾─
-    0x90 │ ─────alloc7─────╼ 00 00 ╾─────alloc8+0x63─────╼ │ ─────╼..╾──────╼
+    0x90 │ ─────alloc6─────╼ 00 00 ╾─────alloc9+0x63─────╼ │ ─────╼..╾──────╼
     0xa0 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0xb0 │ 00 00 00 00                                     │ ....
 }
 
-alloc5 (size: 4, align: 4) {
+alloc4 (size: 4, align: 4) {
     2a 00 00 00                                     │ *...
 }
 
-alloc7 (fn: main)
+alloc6 (fn: main)
 
-alloc8 (size: 100, align: 1) {
+alloc9 (size: 100, align: 1) {
     0x00 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x10 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
     0x20 │ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 │ ................
diff --git a/src/test/ui/consts/array-literal-index-oob.rs b/src/test/ui/consts/array-literal-index-oob.rs
index f36ebf38db4..9b3f735b1f8 100644
--- a/src/test/ui/consts/array-literal-index-oob.rs
+++ b/src/test/ui/consts/array-literal-index-oob.rs
@@ -6,6 +6,4 @@
 fn main() {
     &{ [1, 2, 3][4] };
     //~^ WARN operation will panic
-    //~| WARN reaching this expression at runtime will panic or abort
-    //~| WARN erroneous constant used [const_err]
 }
diff --git a/src/test/ui/consts/array-literal-index-oob.stderr b/src/test/ui/consts/array-literal-index-oob.stderr
index 5916ea6d323..f96b8d48b3e 100644
--- a/src/test/ui/consts/array-literal-index-oob.stderr
+++ b/src/test/ui/consts/array-literal-index-oob.stderr
@@ -10,25 +10,5 @@ note: the lint level is defined here
 LL | #![warn(const_err, unconditional_panic)]
    |                    ^^^^^^^^^^^^^^^^^^^
 
-warning: reaching this expression at runtime will panic or abort
-  --> $DIR/array-literal-index-oob.rs:7:8
-   |
-LL |     &{ [1, 2, 3][4] };
-   |     ---^^^^^^^^^^^^--
-   |        |
-   |        indexing out of bounds: the len is 3 but the index is 4
-   |
-note: the lint level is defined here
-  --> $DIR/array-literal-index-oob.rs:4:9
-   |
-LL | #![warn(const_err, unconditional_panic)]
-   |         ^^^^^^^^^
-
-warning: erroneous constant used
-  --> $DIR/array-literal-index-oob.rs:7:5
-   |
-LL |     &{ [1, 2, 3][4] };
-   |     ^^^^^^^^^^^^^^^^^ referenced constant has errors
-
-warning: 3 warnings emitted
+warning: 1 warning emitted
 
diff --git a/src/test/ui/consts/const-eval/const-eval-query-stack.rs b/src/test/ui/consts/const-eval/const-eval-query-stack.rs
index 8a6f7de1c9f..39803c8f257 100644
--- a/src/test/ui/consts/const-eval/const-eval-query-stack.rs
+++ b/src/test/ui/consts/const-eval/const-eval-query-stack.rs
@@ -1,4 +1,5 @@
-// compile-flags: -Ztreat-err-as-bug
+//~ERROR constructed but no error reported
+// compile-flags: -Ztreat-err-as-bug=2
 // build-fail
 // failure-status: 101
 // rustc-env:RUST_BACKTRACE=1
@@ -15,8 +16,11 @@
 
 #![allow(unconditional_panic)]
 
+#[warn(const_err)]
+const X: i32 = 1 / 0; //~WARN any use of this value will cause an error
+
 fn main() {
-    let x: &'static i32 = &(1 / 0);
-    //~^ ERROR reaching this expression at runtime will panic or abort [const_err]
+    let x: &'static i32 = &X;
+    //~^ ERROR evaluation of constant expression failed
     println!("x={}", x);
 }
diff --git a/src/test/ui/consts/const-eval/const-eval-query-stack.stderr b/src/test/ui/consts/const-eval/const-eval-query-stack.stderr
index 8c57fd37e88..0016d301e59 100644
--- a/src/test/ui/consts/const-eval/const-eval-query-stack.stderr
+++ b/src/test/ui/consts/const-eval/const-eval-query-stack.stderr
@@ -1,18 +1,26 @@
-error: reaching this expression at runtime will panic or abort
-  --> $DIR/const-eval-query-stack.rs:19:28
+warning: any use of this value will cause an error
+  --> $DIR/const-eval-query-stack.rs:20:16
    |
-LL |     let x: &'static i32 = &(1 / 0);
-   |                           -^^^^^^^
-   |                            |
-   |                            dividing by zero
+LL | const X: i32 = 1 / 0;
+   | ---------------^^^^^-
+   |                |
+   |                attempt to divide `1_i32` by zero
+   |
+note: the lint level is defined here
+  --> $DIR/const-eval-query-stack.rs:19:8
    |
-   = note: `#[deny(const_err)]` on by default
+LL | #[warn(const_err)]
+   |        ^^^^^^^^^
 
+error[E0080]: evaluation of constant expression failed
+  --> $DIR/const-eval-query-stack.rs:23:27
+   |
+LL |     let x: &'static i32 = &X;
+   |                           ^-
+   |                            |
+   |                            referenced constant has errors
 query stack during panic:
-#0 [eval_to_allocation_raw] const-evaluating + checking `main::promoted[1]`
-#1 [eval_to_const_value_raw] simplifying constant for the type system `main::promoted[1]`
-#2 [eval_to_const_value_raw] simplifying constant for the type system `main::promoted[1]`
-#3 [normalize_generic_arg_after_erasing_regions] normalizing `main::promoted[1]`
-#4 [optimized_mir] optimizing MIR for `main`
-#5 [collect_and_partition_mono_items] collect_and_partition_mono_items
+#0 [normalize_generic_arg_after_erasing_regions] normalizing `main::promoted[1]`
+#1 [optimized_mir] optimizing MIR for `main`
+#2 [collect_and_partition_mono_items] collect_and_partition_mono_items
 end of query stack
diff --git a/src/test/ui/consts/const-eval/promoted_errors.noopt.stderr b/src/test/ui/consts/const-eval/promoted_errors.noopt.stderr
index ce83d8e9bb0..b71235e51c0 100644
--- a/src/test/ui/consts/const-eval/promoted_errors.noopt.stderr
+++ b/src/test/ui/consts/const-eval/promoted_errors.noopt.stderr
@@ -1,8 +1,8 @@
 warning: this arithmetic operation will overflow
-  --> $DIR/promoted_errors.rs:12:20
+  --> $DIR/promoted_errors.rs:13:5
    |
-LL |     println!("{}", 0u32 - 1);
-   |                    ^^^^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
+LL |     0 - 1
+   |     ^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
    |
 note: the lint level is defined here
   --> $DIR/promoted_errors.rs:9:20
@@ -10,29 +10,24 @@ note: the lint level is defined here
 LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
    |                    ^^^^^^^^^^^^^^^^^^^
 
-warning: this arithmetic operation will overflow
-  --> $DIR/promoted_errors.rs:14:14
-   |
-LL |     let _x = 0u32 - 1;
-   |              ^^^^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:16:20
-   |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ attempt to divide `1_i32` by zero
-   |
-note: the lint level is defined here
-  --> $DIR/promoted_errors.rs:9:41
-   |
-LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
-   |                                         ^^^^^^^^^^^^^^^^^^^
-
-warning: reaching this expression at runtime will panic or abort
-  --> $DIR/promoted_errors.rs:16:20
-   |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ dividing by zero
+warning: any use of this value will cause an error
+  --> $DIR/promoted_errors.rs:13:5
+   |
+LL |       0 - 1
+   |       ^^^^^
+   |       |
+   |       attempt to compute `0_u32 - 1_u32`, which would overflow
+   |       inside `overflow` at $DIR/promoted_errors.rs:13:5
+   |       inside `X` at $DIR/promoted_errors.rs:31:29
+...
+LL | / const X: () = {
+LL | |     let _x: &'static u32 = &overflow();
+LL | |
+LL | |     let _x: &'static i32 = &div_by_zero1();
+...  |
+LL | |     let _x: &'static i32 = &oob();
+LL | | };
+   | |__-
    |
 note: the lint level is defined here
   --> $DIR/promoted_errors.rs:9:9
@@ -40,41 +35,18 @@ note: the lint level is defined here
 LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
    |         ^^^^^^^^^
 
-warning: erroneous constant used
-  --> $DIR/promoted_errors.rs:16:20
-   |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ referenced constant has errors
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:20:14
-   |
-LL |     let _x = 1 / (1 - 1);
-   |              ^^^^^^^^^^^ attempt to divide `1_i32` by zero
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ attempt to divide `1_u32` by zero
-
-warning: reaching this expression at runtime will panic or abort
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ dividing by zero
-
-warning: erroneous constant used
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ referenced constant has errors
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:26:14
+warning: any use of this value will cause an error
+  --> $DIR/promoted_errors.rs:31:28
    |
-LL |     let _x = 1 / (false as u32);
-   |              ^^^^^^^^^^^^^^^^^^ attempt to divide `1_u32` by zero
+LL | / const X: () = {
+LL | |     let _x: &'static u32 = &overflow();
+   | |                            ^^^^^^^^^^^ referenced constant has errors
+LL | |
+LL | |     let _x: &'static i32 = &div_by_zero1();
+...  |
+LL | |     let _x: &'static i32 = &oob();
+LL | | };
+   | |__-
 
-warning: 10 warnings emitted
+warning: 3 warnings emitted
 
diff --git a/src/test/ui/consts/const-eval/promoted_errors.opt.stderr b/src/test/ui/consts/const-eval/promoted_errors.opt.stderr
index 2c66b175cfc..e5108f67e16 100644
--- a/src/test/ui/consts/const-eval/promoted_errors.opt.stderr
+++ b/src/test/ui/consts/const-eval/promoted_errors.opt.stderr
@@ -1,8 +1,8 @@
 warning: this arithmetic operation will overflow
-  --> $DIR/promoted_errors.rs:14:14
+  --> $DIR/promoted_errors.rs:13:5
    |
-LL |     let _x = 0u32 - 1;
-   |              ^^^^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
+LL |     0 - 1
+   |     ^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
    |
 note: the lint level is defined here
   --> $DIR/promoted_errors.rs:9:20
@@ -11,10 +11,10 @@ LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
    |                    ^^^^^^^^^^^^^^^^^^^
 
 warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:16:20
+  --> $DIR/promoted_errors.rs:17:5
    |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ attempt to divide `1_i32` by zero
+LL |     1 / 0
+   |     ^^^^^ attempt to divide `1_i32` by zero
    |
 note: the lint level is defined here
   --> $DIR/promoted_errors.rs:9:41
@@ -22,11 +22,24 @@ note: the lint level is defined here
 LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
    |                                         ^^^^^^^^^^^^^^^^^^^
 
-warning: reaching this expression at runtime will panic or abort
-  --> $DIR/promoted_errors.rs:16:20
+warning: any use of this value will cause an error
+  --> $DIR/promoted_errors.rs:17:5
    |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ dividing by zero
+LL |       1 / 0
+   |       ^^^^^
+   |       |
+   |       attempt to divide `1_i32` by zero
+   |       inside `div_by_zero1` at $DIR/promoted_errors.rs:17:5
+   |       inside `X` at $DIR/promoted_errors.rs:33:29
+...
+LL | / const X: () = {
+LL | |     let _x: &'static u32 = &overflow();
+LL | |
+LL | |     let _x: &'static i32 = &div_by_zero1();
+...  |
+LL | |     let _x: &'static i32 = &oob();
+LL | | };
+   | |__-
    |
 note: the lint level is defined here
   --> $DIR/promoted_errors.rs:9:9
@@ -34,41 +47,18 @@ note: the lint level is defined here
 LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
    |         ^^^^^^^^^
 
-warning: erroneous constant used
-  --> $DIR/promoted_errors.rs:16:20
+warning: any use of this value will cause an error
+  --> $DIR/promoted_errors.rs:33:28
    |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ referenced constant has errors
+LL | / const X: () = {
+LL | |     let _x: &'static u32 = &overflow();
+LL | |
+LL | |     let _x: &'static i32 = &div_by_zero1();
+   | |                            ^^^^^^^^^^^^^^^ referenced constant has errors
+...  |
+LL | |     let _x: &'static i32 = &oob();
+LL | | };
+   | |__-
 
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:20:14
-   |
-LL |     let _x = 1 / (1 - 1);
-   |              ^^^^^^^^^^^ attempt to divide `1_i32` by zero
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ attempt to divide `1_u32` by zero
-
-warning: reaching this expression at runtime will panic or abort
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ dividing by zero
-
-warning: erroneous constant used
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ referenced constant has errors
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:26:14
-   |
-LL |     let _x = 1 / (false as u32);
-   |              ^^^^^^^^^^^^^^^^^^ attempt to divide `1_u32` by zero
-
-warning: 9 warnings emitted
+warning: 4 warnings emitted
 
diff --git a/src/test/ui/consts/const-eval/promoted_errors.opt_with_overflow_checks.stderr b/src/test/ui/consts/const-eval/promoted_errors.opt_with_overflow_checks.stderr
index ce83d8e9bb0..b71235e51c0 100644
--- a/src/test/ui/consts/const-eval/promoted_errors.opt_with_overflow_checks.stderr
+++ b/src/test/ui/consts/const-eval/promoted_errors.opt_with_overflow_checks.stderr
@@ -1,8 +1,8 @@
 warning: this arithmetic operation will overflow
-  --> $DIR/promoted_errors.rs:12:20
+  --> $DIR/promoted_errors.rs:13:5
    |
-LL |     println!("{}", 0u32 - 1);
-   |                    ^^^^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
+LL |     0 - 1
+   |     ^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
    |
 note: the lint level is defined here
   --> $DIR/promoted_errors.rs:9:20
@@ -10,29 +10,24 @@ note: the lint level is defined here
 LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
    |                    ^^^^^^^^^^^^^^^^^^^
 
-warning: this arithmetic operation will overflow
-  --> $DIR/promoted_errors.rs:14:14
-   |
-LL |     let _x = 0u32 - 1;
-   |              ^^^^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:16:20
-   |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ attempt to divide `1_i32` by zero
-   |
-note: the lint level is defined here
-  --> $DIR/promoted_errors.rs:9:41
-   |
-LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
-   |                                         ^^^^^^^^^^^^^^^^^^^
-
-warning: reaching this expression at runtime will panic or abort
-  --> $DIR/promoted_errors.rs:16:20
-   |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ dividing by zero
+warning: any use of this value will cause an error
+  --> $DIR/promoted_errors.rs:13:5
+   |
+LL |       0 - 1
+   |       ^^^^^
+   |       |
+   |       attempt to compute `0_u32 - 1_u32`, which would overflow
+   |       inside `overflow` at $DIR/promoted_errors.rs:13:5
+   |       inside `X` at $DIR/promoted_errors.rs:31:29
+...
+LL | / const X: () = {
+LL | |     let _x: &'static u32 = &overflow();
+LL | |
+LL | |     let _x: &'static i32 = &div_by_zero1();
+...  |
+LL | |     let _x: &'static i32 = &oob();
+LL | | };
+   | |__-
    |
 note: the lint level is defined here
   --> $DIR/promoted_errors.rs:9:9
@@ -40,41 +35,18 @@ note: the lint level is defined here
 LL | #![warn(const_err, arithmetic_overflow, unconditional_panic)]
    |         ^^^^^^^^^
 
-warning: erroneous constant used
-  --> $DIR/promoted_errors.rs:16:20
-   |
-LL |     println!("{}", 1 / (1 - 1));
-   |                    ^^^^^^^^^^^ referenced constant has errors
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:20:14
-   |
-LL |     let _x = 1 / (1 - 1);
-   |              ^^^^^^^^^^^ attempt to divide `1_i32` by zero
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ attempt to divide `1_u32` by zero
-
-warning: reaching this expression at runtime will panic or abort
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ dividing by zero
-
-warning: erroneous constant used
-  --> $DIR/promoted_errors.rs:22:20
-   |
-LL |     println!("{}", 1 / (false as u32));
-   |                    ^^^^^^^^^^^^^^^^^^ referenced constant has errors
-
-warning: this operation will panic at runtime
-  --> $DIR/promoted_errors.rs:26:14
+warning: any use of this value will cause an error
+  --> $DIR/promoted_errors.rs:31:28
    |
-LL |     let _x = 1 / (false as u32);
-   |              ^^^^^^^^^^^^^^^^^^ attempt to divide `1_u32` by zero
+LL | / const X: () = {
+LL | |     let _x: &'static u32 = &overflow();
+   | |                            ^^^^^^^^^^^ referenced constant has errors
+LL | |
+LL | |     let _x: &'static i32 = &div_by_zero1();
+...  |
+LL | |     let _x: &'static i32 = &oob();
+LL | | };
+   | |__-
 
-warning: 10 warnings emitted
+warning: 3 warnings emitted
 
diff --git a/src/test/ui/consts/const-eval/promoted_errors.rs b/src/test/ui/consts/const-eval/promoted_errors.rs
index 142ce75eebc..1f3b3eef509 100644
--- a/src/test/ui/consts/const-eval/promoted_errors.rs
+++ b/src/test/ui/consts/const-eval/promoted_errors.rs
@@ -8,21 +8,34 @@
 
 #![warn(const_err, arithmetic_overflow, unconditional_panic)]
 
+// The only way to have promoteds that fail is in `const fn` called from `const`/`static`.
+const fn overflow() -> u32 {
+    0 - 1 //~WARN arithmetic_overflow
+    //[opt_with_overflow_checks,noopt]~^ WARN any use of this value will cause an error
+}
+const fn div_by_zero1() -> i32 {
+    1 / 0 //[opt]~WARN unconditional_panic
+    //[opt]~^ WARN any use of this value will cause an error
+}
+const fn div_by_zero2() -> i32 {
+    1 / (1-1)
+}
+const fn div_by_zero3() -> i32 {
+    1 / (false as i32)
+}
+const fn oob() -> i32 {
+    [1,2,3][4]
+}
+
+const X: () = {
+    let _x: &'static u32 = &overflow();
+    //[opt_with_overflow_checks,noopt]~^ WARN any use of this value will cause an error
+    let _x: &'static i32 = &div_by_zero1();
+    //[opt]~^ WARN any use of this value will cause an error
+    let _x: &'static i32 = &div_by_zero2();
+    let _x: &'static i32 = &div_by_zero3();
+    let _x: &'static i32 = &oob();
+};
+
 fn main() {
-    println!("{}", 0u32 - 1);
-    //[opt_with_overflow_checks,noopt]~^ WARN [arithmetic_overflow]
-    let _x = 0u32 - 1;
-    //~^ WARN [arithmetic_overflow]
-    println!("{}", 1 / (1 - 1));
-    //~^ WARN [unconditional_panic]
-    //~| WARN panic or abort [const_err]
-    //~| WARN erroneous constant used [const_err]
-    let _x = 1 / (1 - 1);
-    //~^ WARN [unconditional_panic]
-    println!("{}", 1 / (false as u32));
-    //~^ WARN [unconditional_panic]
-    //~| WARN panic or abort [const_err]
-    //~| WARN erroneous constant used [const_err]
-    let _x = 1 / (false as u32);
-    //~^ WARN [unconditional_panic]
 }
diff --git a/src/test/ui/consts/promote-not.rs b/src/test/ui/consts/promote-not.rs
index 1e4d8586b87..0d0c78b0fc2 100644
--- a/src/test/ui/consts/promote-not.rs
+++ b/src/test/ui/consts/promote-not.rs
@@ -44,4 +44,11 @@ fn main() {
     // We must not promote things with interior mutability. Not even if we "project it away".
     let _val: &'static _ = &(Cell::new(1), 2).0; //~ ERROR temporary value dropped while borrowed
     let _val: &'static _ = &(Cell::new(1), 2).1; //~ ERROR temporary value dropped while borrowed
+
+    // No promotion of fallible operations.
+    let _val: &'static _ = &(1/0); //~ ERROR temporary value dropped while borrowed
+    let _val: &'static _ = &(1/(1-1)); //~ ERROR temporary value dropped while borrowed
+    let _val: &'static _ = &(1%0); //~ ERROR temporary value dropped while borrowed
+    let _val: &'static _ = &(1%(1-1)); //~ ERROR temporary value dropped while borrowed
+    let _val: &'static _ = &([1,2,3][4]+1); //~ ERROR temporary value dropped while borrowed
 }
diff --git a/src/test/ui/consts/promote-not.stderr b/src/test/ui/consts/promote-not.stderr
index 6e76d9ee6c1..108d0da7a67 100644
--- a/src/test/ui/consts/promote-not.stderr
+++ b/src/test/ui/consts/promote-not.stderr
@@ -65,7 +65,7 @@ LL |     let _val: &'static _ = &(Cell::new(1), 2).0;
    |               ----------    ^^^^^^^^^^^^^^^^^ creates a temporary which is freed while still in use
    |               |
    |               type annotation requires that borrow lasts for `'static`
-LL |     let _val: &'static _ = &(Cell::new(1), 2).1;
+...
 LL | }
    | - temporary value is freed at the end of this statement
 
@@ -76,9 +76,64 @@ LL |     let _val: &'static _ = &(Cell::new(1), 2).1;
    |               ----------    ^^^^^^^^^^^^^^^^^ creates a temporary which is freed while still in use
    |               |
    |               type annotation requires that borrow lasts for `'static`
+...
+LL | }
+   | - temporary value is freed at the end of this statement
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/promote-not.rs:49:29
+   |
+LL |     let _val: &'static _ = &(1/0);
+   |               ----------    ^^^^^ creates a temporary which is freed while still in use
+   |               |
+   |               type annotation requires that borrow lasts for `'static`
+...
+LL | }
+   | - temporary value is freed at the end of this statement
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/promote-not.rs:50:29
+   |
+LL |     let _val: &'static _ = &(1/(1-1));
+   |               ----------    ^^^^^^^^^ creates a temporary which is freed while still in use
+   |               |
+   |               type annotation requires that borrow lasts for `'static`
+...
+LL | }
+   | - temporary value is freed at the end of this statement
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/promote-not.rs:51:29
+   |
+LL |     let _val: &'static _ = &(1%0);
+   |               ----------    ^^^^^ creates a temporary which is freed while still in use
+   |               |
+   |               type annotation requires that borrow lasts for `'static`
+...
+LL | }
+   | - temporary value is freed at the end of this statement
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/promote-not.rs:52:29
+   |
+LL |     let _val: &'static _ = &(1%(1-1));
+   |               ----------    ^^^^^^^^^ creates a temporary which is freed while still in use
+   |               |
+   |               type annotation requires that borrow lasts for `'static`
+LL |     let _val: &'static _ = &([1,2,3][4]+1);
+LL | }
+   | - temporary value is freed at the end of this statement
+
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/promote-not.rs:53:29
+   |
+LL |     let _val: &'static _ = &([1,2,3][4]+1);
+   |               ----------    ^^^^^^^^^^^^^^ creates a temporary which is freed while still in use
+   |               |
+   |               type annotation requires that borrow lasts for `'static`
 LL | }
    | - temporary value is freed at the end of this statement
 
-error: aborting due to 8 previous errors
+error: aborting due to 13 previous errors
 
 For more information about this error, try `rustc --explain E0716`.
diff --git a/src/test/ui/consts/promoted_div_by_zero.rs b/src/test/ui/consts/promoted_div_by_zero.rs
deleted file mode 100644
index b4503f691ff..00000000000
--- a/src/test/ui/consts/promoted_div_by_zero.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-#![allow(unconditional_panic, const_err)]
-
-// run-fail
-// error-pattern: attempt to divide by zero
-// ignore-emscripten no processes
-
-fn main() {
-    let x = &(1 / (1 - 1));
-}
diff --git a/src/test/ui/consts/promotion.rs b/src/test/ui/consts/promotion.rs
index b6e7127a9b7..3d952964213 100644
--- a/src/test/ui/consts/promotion.rs
+++ b/src/test/ui/consts/promotion.rs
@@ -1,4 +1,4 @@
-// check-pass
+// run-pass
 
 // compile-flags: -O
 
@@ -25,4 +25,14 @@ fn main() {
     // make sure that these do not cause trouble despite overflowing
     baz_u32(&(0-1));
     baz_i32(&-i32::MIN);
+
+    // div-by-non-0 is okay
+    baz_i32(&(1/1));
+    baz_i32(&(1%1));
+
+    // Top-level projections do not get promoted, so no error here.
+    if false {
+        #[allow(unconditional_panic)]
+        baz_i32(&[1,2,3][4]);
+    }
 }