Rollup merge of rust-lang#129517 - cjgillot:known-panic-array, r=pnkfelix

Compute array length from type for unconditional panic lint.

Fixes rust-lang#98444

The cases that involve slicing are harder, so rust-lang#38035 remains open.

Author: workingjubilee

tests/ui-toml/unwrap_used/unwrap_used.fixed

@@ -86,6 +86,7 @@ mod issue9612 {
         util();
     }
 
+    #[allow(unconditional_panic)]
     fn util() {
         let _a: u8 = 4.try_into().unwrap();
         let _a: u8 = 5.try_into().expect("");

tests/ui-toml/unwrap_used/unwrap_used.rs

@@ -86,6 +86,7 @@ mod issue9612 {
         util();
     }
 
+    #[allow(unconditional_panic)]
     fn util() {
         let _a: u8 = 4.try_into().unwrap();
         let _a: u8 = 5.try_into().expect("");

tests/ui-toml/unwrap_used/unwrap_used.stderr

@@ -274,7 +274,7 @@ LL |     let _ = &boxed_slice[1];
    |             ~~~~~~~~~~~~~~~
 
 error: called `.get().unwrap()` on a slice
-  --> tests/ui-toml/unwrap_used/unwrap_used.rs:93:17
+  --> tests/ui-toml/unwrap_used/unwrap_used.rs:94:17
    |
 LL |         let _ = Box::new([0]).get(1).unwrap();
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

tests/ui/get_unwrap.fixed

@@ -70,6 +70,7 @@ fn main() {
 mod issue9909 {
     #![allow(clippy::identity_op, clippy::unwrap_used, dead_code)]
 
+    #[allow(unconditional_panic)]
     fn reduced() {
         let f = &[1, 2, 3];
 

tests/ui/get_unwrap.rs

@@ -70,6 +70,7 @@ fn main() {
 mod issue9909 {
     #![allow(clippy::identity_op, clippy::unwrap_used, dead_code)]
 
+    #[allow(unconditional_panic)]
     fn reduced() {
         let f = &[1, 2, 3];
 

tests/ui/get_unwrap.stderr

@@ -266,7 +266,7 @@ LL |         let _ = some_vec.get_mut(0..1).unwrap().to_vec();
    = help: consider using `expect()` to provide a better panic message
 
 error: called `.get().unwrap()` on a slice
-  --> tests/ui/get_unwrap.rs:77:24
+  --> tests/ui/get_unwrap.rs:78:24
    |
 LL |         let _x: &i32 = f.get(1 + 2).unwrap();
    |                        ^^^^^^^^^^^^^^^^^^^^^
@@ -277,7 +277,7 @@ LL |         let _x: &i32 = &f[1 + 2];
    |                        ~~~~~~~~~
 
 error: called `.get().unwrap()` on a slice
-  --> tests/ui/get_unwrap.rs:80:18
+  --> tests/ui/get_unwrap.rs:81:18
    |
 LL |         let _x = f.get(1 + 2).unwrap().to_string();
    |                  ^^^^^^^^^^^^^^^^^^^^^
@@ -288,7 +288,7 @@ LL |         let _x = f[1 + 2].to_string();
    |                  ~~~~~~~~
 
 error: called `.get().unwrap()` on a slice
-  --> tests/ui/get_unwrap.rs:83:18
+  --> tests/ui/get_unwrap.rs:84:18
    |
 LL |         let _x = f.get(1 + 2).unwrap().abs();
    |                  ^^^^^^^^^^^^^^^^^^^^^
@@ -299,7 +299,7 @@ LL |         let _x = f[1 + 2].abs();
    |                  ~~~~~~~~
 
 error: called `.get_mut().unwrap()` on a slice
-  --> tests/ui/get_unwrap.rs:100:33
+  --> tests/ui/get_unwrap.rs:101:33
    |
 LL |                         let b = rest.get_mut(linidx(j, k) - linidx(i, k) - 1).unwrap();
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^