Fix unsized struct problems in mir eval

crates/hir-ty/src/consteval/tests.rs

@@ -1186,6 +1186,25 @@ fn pattern_matching_ergonomics() {
     );
 }
 
+#[test]
+fn destructing_assignment() {
+    check_number(
+        r#"
+    //- minicore: add
+    const fn f(i: &mut u8) -> &mut u8 {
+        *i += 1;
+        i
+    }
+    const GOAL: u8 = {
+        let mut i = 4;
+        _ = f(&mut i);
+        i
+    };
+        "#,
+        5,
+    );
+}
+
 #[test]
 fn let_else() {
     check_number(
@@ -1745,6 +1764,24 @@ fn function_pointer_in_constants() {
     );
 }
 
+#[test]
+fn function_pointer_and_niche_optimization() {
+    check_number(
+        r#"
+    //- minicore: option
+    const GOAL: i32 = {
+        let f: fn(i32) -> i32 = |x| x + 2;
+        let init = Some(f);
+        match init {
+            Some(t) => t(3),
+            None => 222,
+        }
+    };
+        "#,
+        5,
+    );
+}
+
 #[test]
 fn function_pointer() {
     check_number(
@@ -2359,11 +2396,14 @@ fn const_loop() {
 fn const_transfer_memory() {
     check_number(
         r#"
-    const A1: &i32 = &2;
-    const A2: &i32 = &5;
-    const GOAL: i32 = *A1 + *A2;
+    //- minicore: slice, index, coerce_unsized
+    const A1: &i32 = &1;
+    const A2: &i32 = &10;
+    const A3: [&i32; 3] = [&1, &2, &100];
+    const A4: (i32, &i32) = (1, &1000);
+    const GOAL: i32 = *A1 + *A2 + *A3[2] + *A4.1;
     "#,
-        7,
+        1111,
     );
 }
 
@@ -2634,9 +2674,9 @@ fn exec_limits() {
         }
         sum
     }
-    const GOAL: i32 = f(10000);
+    const GOAL: i32 = f(1000);
     "#,
-        10000 * 10000,
+        1000 * 1000,
     );
 }
 
@@ -2683,7 +2723,7 @@ fn unsized_field() {
     //- minicore: coerce_unsized, index, slice, transmute
     use core::mem::transmute;
 
-    struct Slice([u8]);
+    struct Slice([usize]);
     struct Slice2(Slice);
 
     impl Slice2 {
@@ -2691,19 +2731,19 @@ fn unsized_field() {
             &self.0
         }
 
-        fn as_bytes(&self) -> &[u8] {
+        fn as_bytes(&self) -> &[usize] {
             &self.as_inner().0
         }
     }
 
-    const GOAL: u8 = unsafe {
-        let x: &[u8] = &[1, 2, 3];
+    const GOAL: usize = unsafe {
+        let x: &[usize] = &[1, 2, 3];
         let x: &Slice2 = transmute(x);
         let x = x.as_bytes();
-        x[0] + x[1] + x[2]
+        x[0] + x[1] + x[2] + x.len() * 100
     };
         "#,
-        6,
+        306,
     );
 }
 

crates/hir-ty/src/consteval/tests/intrinsics.rs

@@ -251,6 +251,28 @@ fn wrapping_add() {
     );
 }
 
+#[test]
+fn ptr_offset_from() {
+    check_number(
+        r#"
+        //- minicore: index, slice, coerce_unsized
+        extern "rust-intrinsic" {
+            pub fn ptr_offset_from<T>(ptr: *const T, base: *const T) -> isize;
+            pub fn ptr_offset_from_unsigned<T>(ptr: *const T, base: *const T) -> usize;
+        }
+
+        const GOAL: isize = {
+            let x = [1, 2, 3, 4, 5i32];
+            let r1 = -ptr_offset_from(&x[0], &x[4]);
+            let r2 = ptr_offset_from(&x[3], &x[1]);
+            let r3 = ptr_offset_from_unsigned(&x[3], &x[0]) as isize;
+            r3 * 100 + r2 * 10 + r1
+        };
+        "#,
+        324,
+    );
+}
+
 #[test]
 fn saturating() {
     check_number(