Taint borrowck results without running any borrowck if the MIR body was already tainted

compiler/rustc_borrowck/src/lib.rs

@@ -111,14 +111,16 @@ fn mir_borrowck(tcx: TyCtxt<'_>, def: LocalDefId) -> &BorrowCheckResult<'_> {
     let (input_body, promoted) = tcx.mir_promoted(def);
     debug!("run query mir_borrowck: {}", tcx.def_path_str(def));
 
-    if input_body.borrow().should_skip() {
+    let input_body: &Body<'_> = &input_body.borrow();
-        debug!("Skipping borrowck because of injected body");
+
+    if input_body.should_skip() || input_body.tainted_by_errors.is_some() {
+        debug!("Skipping borrowck because of injected body or tainted body");
         // Let's make up a borrowck result! Fun times!
         let result = BorrowCheckResult {
             concrete_opaque_types: FxIndexMap::default(),
             closure_requirements: None,
             used_mut_upvars: SmallVec::new(),
-            tainted_by_errors: None,
+            tainted_by_errors: input_body.tainted_by_errors,
         };
         return tcx.arena.alloc(result);
     }
@@ -127,7 +129,6 @@ fn mir_borrowck(tcx: TyCtxt<'_>, def: LocalDefId) -> &BorrowCheckResult<'_> {
 
     let infcx =
         tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bind(hir_owner.def_id)).build();
-    let input_body: &Body<'_> = &input_body.borrow();
     let promoted: &IndexSlice<_, _> = &promoted.borrow();
     let opt_closure_req = do_mir_borrowck(&infcx, input_body, promoted, None).0;
     debug!("mir_borrowck done");

tests/ui/consts/promoted_const_call.stderr

@@ -6,26 +6,6 @@ LL |     let _: &'static _ = &id(&Panic);
    |                              |
    |                              the destructor for this type cannot be evaluated in constants
 
-error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call.rs:11:26
-   |
-LL |     let _: &'static _ = &id(&Panic);
-   |            ----------    ^^^^^^^^^^ creates a temporary value 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/promoted_const_call.rs:11:30
-   |
-LL |     let _: &'static _ = &id(&Panic);
-   |            ----------        ^^^^^ - temporary value is freed at the end of this statement
-   |            |                 |
-   |            |                 creates a temporary value which is freed while still in use
-   |            type annotation requires that borrow lasts for `'static`
-
 error[E0716]: temporary value dropped while borrowed
   --> $DIR/promoted_const_call.rs:17:26
    |
@@ -68,7 +48,7 @@ LL |     let _: &'static _ = &&(Panic, 0).1;
 LL | }
    | - temporary value is freed at the end of this statement
 
-error: aborting due to 7 previous errors
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0493, E0716.
 For more information about an error, try `rustc --explain E0493`.

tests/ui/consts/promoted_const_call3.rs

@@ -2,13 +2,14 @@ pub const fn id<T>(x: T) -> T { x }
 pub const C: () = {
     let _: &'static _ = &String::new();
     //~^ ERROR: destructor of `String` cannot be evaluated at compile-time
-    //~| ERROR: temporary value dropped while borrowed
+};
 
+pub const _: () = {
     let _: &'static _ = &id(&String::new());
     //~^ ERROR: destructor of `String` cannot be evaluated at compile-time
-    //~| ERROR: temporary value dropped while borrowed
+};
-    //~| ERROR: temporary value dropped while borrowed
 
+pub const _: () = {
     let _: &'static _ = &std::mem::ManuallyDrop::new(String::new());
     //~^ ERROR: temporary value dropped while borrowed
 };

tests/ui/consts/promoted_const_call3.stderr

@@ -1,53 +1,22 @@
 error[E0493]: destructor of `String` cannot be evaluated at compile-time
-  --> $DIR/promoted_const_call3.rs:7:30
+  --> $DIR/promoted_const_call3.rs:3:26
+   |
+LL |     let _: &'static _ = &String::new();
+   |                          ^^^^^^^^^^^^^ the destructor for this type cannot be evaluated in constants
+LL |
+LL | };
+   | - value is dropped here
+
+error[E0493]: destructor of `String` cannot be evaluated at compile-time
+  --> $DIR/promoted_const_call3.rs:8:30
    |
 LL |     let _: &'static _ = &id(&String::new());
    |                              ^^^^^^^^^^^^^ - value is dropped here
    |                              |
    |                              the destructor for this type cannot be evaluated in constants
 
-error[E0493]: destructor of `String` cannot be evaluated at compile-time
-  --> $DIR/promoted_const_call3.rs:3:26
-   |
-LL |     let _: &'static _ = &String::new();
-   |                          ^^^^^^^^^^^^^ the destructor for this type cannot be evaluated in constants
-...
-LL | };
-   | - value is dropped here
-
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call3.rs:3:26
+  --> $DIR/promoted_const_call3.rs:13:26
-   |
-LL |     let _: &'static _ = &String::new();
-   |            ----------    ^^^^^^^^^^^^^ creates a temporary value 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/promoted_const_call3.rs:7:26
-   |
-LL |     let _: &'static _ = &id(&String::new());
-   |            ----------    ^^^^^^^^^^^^^^^^^^ creates a temporary value 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/promoted_const_call3.rs:7:30
-   |
-LL |     let _: &'static _ = &id(&String::new());
-   |            ----------        ^^^^^^^^^^^^^ - temporary value is freed at the end of this statement
-   |            |                 |
-   |            |                 creates a temporary value which is freed while still in use
-   |            type annotation requires that borrow lasts for `'static`
-
-error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call3.rs:12:26
    |
 LL |     let _: &'static _ = &std::mem::ManuallyDrop::new(String::new());
    |            ----------    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@@ -58,7 +27,7 @@ LL | };
    | - temporary value is freed at the end of this statement
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call3.rs:17:26
+  --> $DIR/promoted_const_call3.rs:18:26
    |
 LL |     let _: &'static _ = &String::new();
    |            ----------    ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@@ -69,7 +38,7 @@ LL | }
    | - temporary value is freed at the end of this statement
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call3.rs:20:26
+  --> $DIR/promoted_const_call3.rs:21:26
    |
 LL |     let _: &'static _ = &id(&String::new());
    |            ----------    ^^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@@ -80,7 +49,7 @@ LL | }
    | - temporary value is freed at the end of this statement
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call3.rs:20:30
+  --> $DIR/promoted_const_call3.rs:21:30
    |
 LL |     let _: &'static _ = &id(&String::new());
    |            ----------        ^^^^^^^^^^^^^ - temporary value is freed at the end of this statement
@@ -89,7 +58,7 @@ LL |     let _: &'static _ = &id(&String::new());
    |            type annotation requires that borrow lasts for `'static`
 
 error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call3.rs:24:26
+  --> $DIR/promoted_const_call3.rs:25:26
    |
 LL |     let _: &'static _ = &std::mem::ManuallyDrop::new(String::new());
    |            ----------    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@@ -99,7 +68,7 @@ LL |
 LL | }
    | - temporary value is freed at the end of this statement
 
-error: aborting due to 10 previous errors
+error: aborting due to 7 previous errors
 
 Some errors have detailed explanations: E0493, E0716.
 For more information about an error, try `rustc --explain E0493`.

tests/ui/consts/promoted_const_call5.rs

@@ -25,9 +25,9 @@ pub const fn new_manually_drop<T>(t: T) -> std::mem::ManuallyDrop<T>  {
 const C: () = {
     let _: &'static _ = &id(&new_string());
     //~^ ERROR destructor of `String` cannot be evaluated at compile-time
-    //~| ERROR: temporary value dropped while borrowed
+};
-    //~| ERROR: temporary value dropped while borrowed
 
+const _: () = {
     let _: &'static _ = &new_manually_drop(new_string());
     //~^ ERROR: temporary value dropped while borrowed
 };

tests/ui/consts/promoted_const_call5.stderr

@@ -6,26 +6,6 @@ LL |     let _: &'static _ = &id(&new_string());
    |                              |
    |                              the destructor for this type cannot be evaluated in constants
 
-error[E0716]: temporary value dropped while borrowed
-  --> $DIR/promoted_const_call5.rs:26:26
-   |
-LL |     let _: &'static _ = &id(&new_string());
-   |            ----------    ^^^^^^^^^^^^^^^^^ creates a temporary value 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/promoted_const_call5.rs:26:30
-   |
-LL |     let _: &'static _ = &id(&new_string());
-   |                          ----^^^^^^^^^^^^-- temporary value is freed at the end of this statement
-   |                          |   |
-   |                          |   creates a temporary value which is freed while still in use
-   |                          argument requires that borrow lasts for `'static`
-
 error[E0716]: temporary value dropped while borrowed
   --> $DIR/promoted_const_call5.rs:31:26
    |
@@ -68,7 +48,7 @@ LL |
 LL | }
    | - temporary value is freed at the end of this statement
 
-error: aborting due to 7 previous errors
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0493, E0716.
 For more information about an error, try `rustc --explain E0493`.

tests/ui/mir/drop-elaboration-after-borrowck-error.rs

@@ -6,7 +6,6 @@ static A: () = {
     //~^ ERROR destructor of
     a[0] = String::new();
     //~^ ERROR destructor of
-    //~| ERROR binding `a` isn't initialized
 };
 
 struct B<T>([T; 1]);
@@ -17,7 +16,6 @@ impl<T> B<T> {
         //~^ ERROR destructor of
         self.0[0] = other;
         //~^ ERROR destructor of
-        //~| ERROR use of moved value
         self
     }
 }

tests/ui/mir/drop-elaboration-after-borrowck-error.stderr

@@ -16,22 +16,8 @@ LL |     let a: [String; 1];
 LL | };
    | - value is dropped here
 
-error[E0381]: used binding `a` isn't initialized
-  --> $DIR/drop-elaboration-after-borrowck-error.rs:7:5
-   |
-LL |     let a: [String; 1];
-   |         - binding declared here but left uninitialized
-LL |
-LL |     a[0] = String::new();
-   |     ^^^^ `a` used here but it isn't initialized
-   |
-help: consider assigning a value
-   |
-LL |     let a: [String; 1] = todo!();
-   |                        +++++++++
-
 error[E0493]: destructor of `T` cannot be evaluated at compile-time
-  --> $DIR/drop-elaboration-after-borrowck-error.rs:18:9
+  --> $DIR/drop-elaboration-after-borrowck-error.rs:17:9
    |
 LL |         self.0[0] = other;
    |         ^^^^^^^^^
@@ -40,7 +26,7 @@ LL |         self.0[0] = other;
    |         value is dropped here
 
 error[E0493]: destructor of `B<T>` cannot be evaluated at compile-time
-  --> $DIR/drop-elaboration-after-borrowck-error.rs:16:13
+  --> $DIR/drop-elaboration-after-borrowck-error.rs:15:13
    |
 LL |         let _this = self;
    |             ^^^^^ the destructor for this type cannot be evaluated in constant functions
@@ -48,18 +34,6 @@ LL |         let _this = self;
 LL |     }
    |     - value is dropped here
 
-error[E0382]: use of moved value: `self.0`
+error: aborting due to 4 previous errors
-  --> $DIR/drop-elaboration-after-borrowck-error.rs:18:9
-   |
-LL |     pub const fn f(mut self, other: T) -> Self {
-   |                    -------- move occurs because `self` has type `B<T>`, which does not implement the `Copy` trait
-LL |         let _this = self;
-   |                     ---- value moved here
-LL |
-LL |         self.0[0] = other;
-   |         ^^^^^^^^^ value used here after move
 
-error: aborting due to 6 previous errors
+For more information about this error, try `rustc --explain E0493`.
-
-Some errors have detailed explanations: E0381, E0382, E0493.
-For more information about an error, try `rustc --explain E0381`.

tests/ui/static/static-drop-scope.rs

@@ -6,11 +6,9 @@ impl Drop for WithDtor {
 
 static PROMOTION_FAIL_S: Option<&'static WithDtor> = Some(&WithDtor);
 //~^ ERROR destructor of
-//~| ERROR temporary value dropped while borrowed
 
 const PROMOTION_FAIL_C: Option<&'static WithDtor> = Some(&WithDtor);
 //~^ ERROR destructor of
-//~| ERROR temporary value dropped while borrowed
 
 static EARLY_DROP_S: i32 = (WithDtor, 0).1;
 //~^ ERROR destructor of

tests/ui/static/static-drop-scope.stderr

@@ -6,36 +6,16 @@ LL | static PROMOTION_FAIL_S: Option<&'static WithDtor> = Some(&WithDtor);
    |                                                            |
    |                                                            the destructor for this type cannot be evaluated in statics
 
-error[E0716]: temporary value dropped while borrowed
-  --> $DIR/static-drop-scope.rs:7:60
-   |
-LL | static PROMOTION_FAIL_S: Option<&'static WithDtor> = Some(&WithDtor);
-   |                                                      ------^^^^^^^^-
-   |                                                      |     |       |
-   |                                                      |     |       temporary value is freed at the end of this statement
-   |                                                      |     creates a temporary value which is freed while still in use
-   |                                                      using this value as a static requires that borrow lasts for `'static`
-
 error[E0493]: destructor of `WithDtor` cannot be evaluated at compile-time
-  --> $DIR/static-drop-scope.rs:11:59
+  --> $DIR/static-drop-scope.rs:10:59
    |
 LL | const PROMOTION_FAIL_C: Option<&'static WithDtor> = Some(&WithDtor);
    |                                                           ^^^^^^^^- value is dropped here
    |                                                           |
    |                                                           the destructor for this type cannot be evaluated in constants
 
-error[E0716]: temporary value dropped while borrowed
-  --> $DIR/static-drop-scope.rs:11:59
-   |
-LL | const PROMOTION_FAIL_C: Option<&'static WithDtor> = Some(&WithDtor);
-   |                                                     ------^^^^^^^^-
-   |                                                     |     |       |
-   |                                                     |     |       temporary value is freed at the end of this statement
-   |                                                     |     creates a temporary value which is freed while still in use
-   |                                                     using this value as a constant requires that borrow lasts for `'static`
-
 error[E0493]: destructor of `(WithDtor, i32)` cannot be evaluated at compile-time
-  --> $DIR/static-drop-scope.rs:15:28
+  --> $DIR/static-drop-scope.rs:13:28
    |
 LL | static EARLY_DROP_S: i32 = (WithDtor, 0).1;
    |                            ^^^^^^^^^^^^^ - value is dropped here
@@ -43,7 +23,7 @@ LL | static EARLY_DROP_S: i32 = (WithDtor, 0).1;
    |                            the destructor for this type cannot be evaluated in statics
 
 error[E0493]: destructor of `(WithDtor, i32)` cannot be evaluated at compile-time
-  --> $DIR/static-drop-scope.rs:18:27
+  --> $DIR/static-drop-scope.rs:16:27
    |
 LL | const EARLY_DROP_C: i32 = (WithDtor, 0).1;
    |                           ^^^^^^^^^^^^^ - value is dropped here
@@ -51,7 +31,7 @@ LL | const EARLY_DROP_C: i32 = (WithDtor, 0).1;
    |                           the destructor for this type cannot be evaluated in constants
 
 error[E0493]: destructor of `T` cannot be evaluated at compile-time
-  --> $DIR/static-drop-scope.rs:21:24
+  --> $DIR/static-drop-scope.rs:19:24
    |
 LL | const fn const_drop<T>(_: T) {}
    |                        ^      - value is dropped here
@@ -59,7 +39,7 @@ LL | const fn const_drop<T>(_: T) {}
    |                        the destructor for this type cannot be evaluated in constant functions
 
 error[E0493]: destructor of `(T, ())` cannot be evaluated at compile-time
-  --> $DIR/static-drop-scope.rs:25:5
+  --> $DIR/static-drop-scope.rs:23:5
    |
 LL |     (x, ()).1
    |     ^^^^^^^ the destructor for this type cannot be evaluated in constant functions
@@ -68,7 +48,7 @@ LL | }
    | - value is dropped here
 
 error[E0493]: destructor of `(Option<WithDtor>, i32)` cannot be evaluated at compile-time
-  --> $DIR/static-drop-scope.rs:29:34
+  --> $DIR/static-drop-scope.rs:27:34
    |
 LL | const EARLY_DROP_C_OPTION: i32 = (Some(WithDtor), 0).1;
    |                                  ^^^^^^^^^^^^^^^^^^^ - value is dropped here
@@ -76,14 +56,13 @@ LL | const EARLY_DROP_C_OPTION: i32 = (Some(WithDtor), 0).1;
    |                                  the destructor for this type cannot be evaluated in constants
 
 error[E0493]: destructor of `(Option<WithDtor>, i32)` cannot be evaluated at compile-time
-  --> $DIR/static-drop-scope.rs:34:43
+  --> $DIR/static-drop-scope.rs:32:43
    |
 LL | const EARLY_DROP_C_OPTION_CONSTANT: i32 = (HELPER, 0).1;
    |                                           ^^^^^^^^^^^ - value is dropped here
    |                                           |
    |                                           the destructor for this type cannot be evaluated in constants
 
-error: aborting due to 10 previous errors
+error: aborting due to 8 previous errors
 
-Some errors have detailed explanations: E0493, E0716.
+For more information about this error, try `rustc --explain E0493`.
-For more information about an error, try `rustc --explain E0493`.