Add ui test.

tests/ui/binding/issue-53114-safety-checks.rs

@@ -30,6 +30,20 @@ fn let_wild_gets_unsafe_field() {
     let (_,) = (&u2.a,); //~ ERROR   [E0133]
 }
 
+fn let_ascribe_gets_unsafe_field() {
+    let u1 = U { a: I(0) };
+    let u2 = U { a: I(1) };
+    let p = P { a: &2, b: &3 };
+    let _: _ = &p.b;  //~ ERROR    reference to packed field
+    let _: _ = u1.a;  //~ ERROR  [E0133]
+    let _: _ = &u2.a; //~ ERROR  [E0133]
+
+    // variation on above with `_` in substructure
+    let (_,): _ = (&p.b,);  //~ ERROR     reference to packed field
+    let (_,): _ = (u1.a,);  //~ ERROR   [E0133]
+    let (_,): _ = (&u2.a,); //~ ERROR   [E0133]
+}
+
 fn match_unsafe_field_to_wild() {
     let u1 = U { a: I(0) };
     let u2 = U { a: I(1) };

tests/ui/binding/issue-53114-safety-checks.stderr

@@ -17,7 +17,25 @@ LL |     let (_,) = (&p.b,);
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
 error[E0793]: reference to packed field is unaligned
-  --> $DIR/issue-53114-safety-checks.rs:37:11
+  --> $DIR/issue-53114-safety-checks.rs:37:16
+   |
+LL |     let _: _ = &p.b;
+   |                ^^^^
+   |
+   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
+
+error[E0793]: reference to packed field is unaligned
+  --> $DIR/issue-53114-safety-checks.rs:42:20
+   |
+LL |     let (_,): _ = (&p.b,);
+   |                    ^^^^
+   |
+   = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced)
+   = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
+
+error[E0793]: reference to packed field is unaligned
+  --> $DIR/issue-53114-safety-checks.rs:51:11
    |
 LL |     match &p.b  { _ => { } }
    |           ^^^^
@@ -26,7 +44,7 @@ LL |     match &p.b  { _ => { } }
    = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers)
 
 error[E0793]: reference to packed field is unaligned
-  --> $DIR/issue-53114-safety-checks.rs:42:12
+  --> $DIR/issue-53114-safety-checks.rs:56:12
    |
 LL |     match (&p.b,)  { (_,) => { } }
    |            ^^^^
@@ -59,7 +77,39 @@ LL |     let (_,) = (&u2.a,);
    = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
 
 error[E0133]: access to union field is unsafe and requires unsafe function or block
-  --> $DIR/issue-53114-safety-checks.rs:38:11
+  --> $DIR/issue-53114-safety-checks.rs:38:12
+   |
+LL |     let _: _ = u1.a;
+   |            ^ access to union field
+   |
+   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
+
+error[E0133]: access to union field is unsafe and requires unsafe function or block
+  --> $DIR/issue-53114-safety-checks.rs:39:16
+   |
+LL |     let _: _ = &u2.a;
+   |                ^^^^^ access to union field
+   |
+   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
+
+error[E0133]: access to union field is unsafe and requires unsafe function or block
+  --> $DIR/issue-53114-safety-checks.rs:43:20
+   |
+LL |     let (_,): _ = (u1.a,);
+   |                    ^^^^ access to union field
+   |
+   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
+
+error[E0133]: access to union field is unsafe and requires unsafe function or block
+  --> $DIR/issue-53114-safety-checks.rs:44:20
+   |
+LL |     let (_,): _ = (&u2.a,);
+   |                    ^^^^^ access to union field
+   |
+   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
+
+error[E0133]: access to union field is unsafe and requires unsafe function or block
+  --> $DIR/issue-53114-safety-checks.rs:52:11
    |
 LL |     match u1.a  { _ => { } }
    |           ^^^^ access to union field
@@ -67,7 +117,7 @@ LL |     match u1.a  { _ => { } }
    = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
 
 error[E0133]: access to union field is unsafe and requires unsafe function or block
-  --> $DIR/issue-53114-safety-checks.rs:39:11
+  --> $DIR/issue-53114-safety-checks.rs:53:11
    |
 LL |     match &u2.a { _ => { } }
    |           ^^^^^ access to union field
@@ -75,7 +125,7 @@ LL |     match &u2.a { _ => { } }
    = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
 
 error[E0133]: access to union field is unsafe and requires unsafe function or block
-  --> $DIR/issue-53114-safety-checks.rs:43:12
+  --> $DIR/issue-53114-safety-checks.rs:57:12
    |
 LL |     match (u1.a,)  { (_,) => { } }
    |            ^^^^ access to union field
@@ -83,14 +133,14 @@ LL |     match (u1.a,)  { (_,) => { } }
    = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
 
 error[E0133]: access to union field is unsafe and requires unsafe function or block
-  --> $DIR/issue-53114-safety-checks.rs:44:12
+  --> $DIR/issue-53114-safety-checks.rs:58:12
    |
 LL |     match (&u2.a,) { (_,) => { } }
    |            ^^^^^ access to union field
    |
    = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
 
-error: aborting due to 11 previous errors
+error: aborting due to 17 previous errors
 
 Some errors have detailed explanations: E0133, E0793.
 For more information about an error, try `rustc --explain E0133`.

tests/ui/borrowck/let_underscore_temporary.rs

@@ -0,0 +1,27 @@
+// check-pass
+
+fn let_underscore(string: &Option<&str>, mut num: Option<i32>) {
+    let _ = if let Some(s) = *string { s.len() } else { 0 };
+    let _ = if let Some(s) = &num { s } else { &0 };
+    let _ = if let Some(s) = &mut num {
+        *s += 1;
+        s
+    } else {
+        &mut 0
+    };
+    let _ = if let Some(ref s) = num { s } else { &0 };
+    let _ = if let Some(mut s) = num {
+        s += 1;
+        s
+    } else {
+        0
+    };
+    let _ = if let Some(ref mut s) = num {
+        *s += 1;
+        s
+    } else {
+        &mut 0
+    };
+}
+
+fn main() {}

tests/ui/unsafe/unsafe-fn-deref-ptr.mir.stderr

@@ -1,11 +1,19 @@
 error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
-  --> $DIR/unsafe-fn-deref-ptr.rs:5:12
+  --> $DIR/unsafe-fn-deref-ptr.rs:6:12
+   |
+LL |     let _: u8 = *p;
+   |            ^^ dereference of raw pointer
+   |
+   = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
+
+error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
+  --> $DIR/unsafe-fn-deref-ptr.rs:7:12
    |
 LL |     return *p;
    |            ^^ dereference of raw pointer
    |
    = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0133`.

tests/ui/unsafe/unsafe-fn-deref-ptr.rs

@@ -2,6 +2,8 @@
 // [thir]compile-flags: -Z thir-unsafeck
 
 fn f(p: *const u8) -> u8 {
+    let _ = *p; //[thir]~ ERROR dereference of raw pointer is unsafe
+    let _: u8 = *p; //~ ERROR dereference of raw pointer is unsafe
     return *p; //~ ERROR dereference of raw pointer is unsafe
 }
 

tests/ui/unsafe/unsafe-fn-deref-ptr.thir.stderr

@@ -1,11 +1,27 @@
 error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
-  --> $DIR/unsafe-fn-deref-ptr.rs:5:12
+  --> $DIR/unsafe-fn-deref-ptr.rs:5:13
+   |
+LL |     let _ = *p;
+   |             ^^ dereference of raw pointer
+   |
+   = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
+
+error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
+  --> $DIR/unsafe-fn-deref-ptr.rs:6:17
+   |
+LL |     let _: u8 = *p;
+   |                 ^^ dereference of raw pointer
+   |
+   = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
+
+error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
+  --> $DIR/unsafe-fn-deref-ptr.rs:7:12
    |
 LL |     return *p;
    |            ^^ dereference of raw pointer
    |
    = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
 
-error: aborting due to previous error
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0133`.