Auto merge of #58673 - matthewjasper:typeck-ptr-coercions, r=pnkfelix

[NLL] Type check operations with pointer types

It seems these were forgotten about. Moving to `Rvalue::AddressOf` simplifies the coercions from references, but I want this to be fixed as soon as possible.

r? @pnkfelix

src/test/ui/nll/type-check-pointer-coercions.rs

@@ -0,0 +1,39 @@
+#![feature(nll)]
+
+fn shared_to_const<'a, 'b>(x: &&'a i32) -> *const &'b i32 {
+    x   //~ ERROR
+}
+
+fn unique_to_const<'a, 'b>(x: &mut &'a i32) -> *const &'b i32 {
+    x   //~ ERROR
+}
+
+fn unique_to_mut<'a, 'b>(x: &mut &'a i32) -> *mut &'b i32 {
+    // Two errors because *mut is invariant
+    x   //~ ERROR
+        //~| ERROR
+}
+
+fn mut_to_const<'a, 'b>(x: *mut &'a i32) -> *const &'b i32 {
+    x   //~ ERROR
+}
+
+fn array_elem<'a, 'b>(x: &'a i32) -> *const &'b i32 {
+    let z = &[x; 3];
+    let y = z as *const &i32;
+    y   //~ ERROR
+}
+
+fn array_coerce<'a, 'b>(x: &'a i32) -> *const [&'b i32; 3] {
+    let z = &[x; 3];
+    let y = z as *const [&i32; 3];
+    y   //~ ERROR
+}
+
+fn nested_array<'a, 'b>(x: &'a i32) -> *const [&'b i32; 2] {
+    let z = &[[x; 2]; 3];
+    let y = z as *const [&i32; 2];
+    y   //~ ERROR
+}
+
+fn main() {}

src/test/ui/nll/type-check-pointer-coercions.stderr

@@ -0,0 +1,87 @@
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-coercions.rs:4:5
+   |
+LL | fn shared_to_const<'a, 'b>(x: &&'a i32) -> *const &'b i32 {
+   |                    --  -- lifetime `'b` defined here
+   |                    |
+   |                    lifetime `'a` defined here
+LL |     x   //~ ERROR
+   |     ^ returning this value requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-coercions.rs:8:5
+   |
+LL | fn unique_to_const<'a, 'b>(x: &mut &'a i32) -> *const &'b i32 {
+   |                    --  -- lifetime `'b` defined here
+   |                    |
+   |                    lifetime `'a` defined here
+LL |     x   //~ ERROR
+   |     ^ returning this value requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-coercions.rs:13:5
+   |
+LL | fn unique_to_mut<'a, 'b>(x: &mut &'a i32) -> *mut &'b i32 {
+   |                  --  -- lifetime `'b` defined here
+   |                  |
+   |                  lifetime `'a` defined here
+LL |     // Two errors because *mut is invariant
+LL |     x   //~ ERROR
+   |     ^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-coercions.rs:13:5
+   |
+LL | fn unique_to_mut<'a, 'b>(x: &mut &'a i32) -> *mut &'b i32 {
+   |                  --  -- lifetime `'b` defined here
+   |                  |
+   |                  lifetime `'a` defined here
+LL |     // Two errors because *mut is invariant
+LL |     x   //~ ERROR
+   |     ^ returning this value requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-coercions.rs:18:5
+   |
+LL | fn mut_to_const<'a, 'b>(x: *mut &'a i32) -> *const &'b i32 {
+   |                 --  -- lifetime `'b` defined here
+   |                 |
+   |                 lifetime `'a` defined here
+LL |     x   //~ ERROR
+   |     ^ returning this value requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-coercions.rs:24:5
+   |
+LL | fn array_elem<'a, 'b>(x: &'a i32) -> *const &'b i32 {
+   |               --  -- lifetime `'b` defined here
+   |               |
+   |               lifetime `'a` defined here
+...
+LL |     y   //~ ERROR
+   |     ^ returning this value requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-coercions.rs:30:5
+   |
+LL | fn array_coerce<'a, 'b>(x: &'a i32) -> *const [&'b i32; 3] {
+   |                 --  -- lifetime `'b` defined here
+   |                 |
+   |                 lifetime `'a` defined here
+...
+LL |     y   //~ ERROR
+   |     ^ returning this value requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-coercions.rs:36:5
+   |
+LL | fn nested_array<'a, 'b>(x: &'a i32) -> *const [&'b i32; 2] {
+   |                 --  -- lifetime `'b` defined here
+   |                 |
+   |                 lifetime `'a` defined here
+...
+LL |     y   //~ ERROR
+   |     ^ returning this value requires that `'a` must outlive `'b`
+
+error: aborting due to 8 previous errors
+

src/test/ui/nll/type-check-pointer-comparisons.rs

@@ -0,0 +1,33 @@
+#![feature(nll)]
+
+// Check that we assert that pointers have a common subtype for comparisons
+
+fn compare_const<'a, 'b>(x: *const &mut &'a i32, y: *const &mut &'b i32) {
+    x == y;
+    //~^ ERROR lifetime may not live long enough
+    //~| ERROR lifetime may not live long enough
+}
+
+fn compare_mut<'a, 'b>(x: *mut &'a i32, y: *mut &'b i32) {
+    x == y;
+    //~^ ERROR lifetime may not live long enough
+    //~| ERROR lifetime may not live long enough
+}
+
+fn compare_fn_ptr<'a, 'b, 'c>(f: fn(&'c mut &'a i32), g: fn(&'c mut &'b i32)) {
+    f == g;
+    //~^ ERROR lifetime may not live long enough
+    //~| ERROR lifetime may not live long enough
+}
+
+fn compare_hr_fn_ptr<'a>(f: fn(&'a i32), g: fn(&i32)) {
+    // Ideally this should compile with the operands swapped as well, but HIR
+    // type checking prevents it (and stops compilation) for now.
+    f == g; // OK
+}
+
+fn compare_const_fn_ptr<'a>(f: *const fn(&'a i32), g: *const fn(&i32)) {
+    f == g; // OK
+}
+
+fn main() {}

src/test/ui/nll/type-check-pointer-comparisons.stderr

@@ -0,0 +1,62 @@
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-comparisons.rs:6:5
+   |
+LL | fn compare_const<'a, 'b>(x: *const &mut &'a i32, y: *const &mut &'b i32) {
+   |                  --  -- lifetime `'b` defined here
+   |                  |
+   |                  lifetime `'a` defined here
+LL |     x == y;
+   |     ^ requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-comparisons.rs:6:10
+   |
+LL | fn compare_const<'a, 'b>(x: *const &mut &'a i32, y: *const &mut &'b i32) {
+   |                  --  -- lifetime `'b` defined here
+   |                  |
+   |                  lifetime `'a` defined here
+LL |     x == y;
+   |          ^ requires that `'b` must outlive `'a`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-comparisons.rs:12:5
+   |
+LL | fn compare_mut<'a, 'b>(x: *mut &'a i32, y: *mut &'b i32) {
+   |                --  -- lifetime `'b` defined here
+   |                |
+   |                lifetime `'a` defined here
+LL |     x == y;
+   |     ^ requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-comparisons.rs:12:10
+   |
+LL | fn compare_mut<'a, 'b>(x: *mut &'a i32, y: *mut &'b i32) {
+   |                --  -- lifetime `'b` defined here
+   |                |
+   |                lifetime `'a` defined here
+LL |     x == y;
+   |          ^ requires that `'b` must outlive `'a`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-comparisons.rs:18:5
+   |
+LL | fn compare_fn_ptr<'a, 'b, 'c>(f: fn(&'c mut &'a i32), g: fn(&'c mut &'b i32)) {
+   |                   --  -- lifetime `'b` defined here
+   |                   |
+   |                   lifetime `'a` defined here
+LL |     f == g;
+   |     ^ requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/type-check-pointer-comparisons.rs:18:10
+   |
+LL | fn compare_fn_ptr<'a, 'b, 'c>(f: fn(&'c mut &'a i32), g: fn(&'c mut &'b i32)) {
+   |                   --  -- lifetime `'b` defined here
+   |                   |
+   |                   lifetime `'a` defined here
+LL |     f == g;
+   |          ^ requires that `'b` must outlive `'a`
+
+error: aborting due to 6 previous errors
+