Merge pull request #37173 from brson/stable-next

[stable] Backports for 1.12.1

Author: brson

mk/main.mk

@@ -13,7 +13,7 @@
 ######################################################################
 
 # The version number
-CFG_RELEASE_NUM=1.12.0
+CFG_RELEASE_NUM=1.12.1
 
 # An optional number to put after the label, e.g. '.2' -> '-beta.2'
 # NB Make sure it starts with a dot to conform to semver pre-release

src/librustc/ty/flags.rs

@@ -107,6 +107,11 @@ impl FlagComputation {
             }
 
             &ty::TyProjection(ref data) => {
+                // currently we can't normalize projections that
+                // include bound regions, so track those separately.
+                if !data.has_escaping_regions() {
+                    self.add_flags(TypeFlags::HAS_NORMALIZABLE_PROJECTION);
+                }
                 self.add_flags(TypeFlags::HAS_PROJECTION);
                 self.add_projection_ty(data);
             }

src/librustc/ty/fold.rs

@@ -105,7 +105,7 @@ pub trait TypeFoldable<'tcx>: fmt::Debug + Clone {
                              TypeFlags::HAS_FREE_REGIONS |
                              TypeFlags::HAS_TY_INFER |
                              TypeFlags::HAS_PARAMS |
-                             TypeFlags::HAS_PROJECTION |
+                             TypeFlags::HAS_NORMALIZABLE_PROJECTION |
                              TypeFlags::HAS_TY_ERR |
                              TypeFlags::HAS_SELF)
     }

src/librustc/ty/item_path.rs

@@ -305,7 +305,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     /// Returns the def-id of `def_id`'s parent in the def tree. If
     /// this returns `None`, then `def_id` represents a crate root or
     /// inlined root.
-    fn parent_def_id(&self, def_id: DefId) -> Option<DefId> {
+    pub fn parent_def_id(&self, def_id: DefId) -> Option<DefId> {
         let key = self.def_key(def_id);
         key.parent.map(|index| DefId { krate: def_id.krate, index: index })
     }

src/librustc/ty/mod.rs

@@ -527,6 +527,10 @@ bitflags! {
         // Only set for TyInfer other than Fresh.
         const KEEP_IN_LOCAL_TCX  = 1 << 11,
 
+        // Is there a projection that does not involve a bound region?
+        // Currently we can't normalize projections w/ bound regions.
+        const HAS_NORMALIZABLE_PROJECTION = 1 << 12,
+
         const NEEDS_SUBST        = TypeFlags::HAS_PARAMS.bits |
                                    TypeFlags::HAS_SELF.bits |
                                    TypeFlags::HAS_RE_EARLY_BOUND.bits,

src/librustc_mir/build/expr/as_lvalue.rs

@@ -96,6 +96,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             ExprKind::LogicalOp { .. } |
             ExprKind::Box { .. } |
             ExprKind::Cast { .. } |
+            ExprKind::Use { .. } |
             ExprKind::NeverToAny { .. } |
             ExprKind::ReifyFnPointer { .. } |
             ExprKind::UnsafeFnPointer { .. } |

src/librustc_mir/build/expr/as_rvalue.rs

@@ -115,6 +115,10 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 let source = unpack!(block = this.as_operand(block, source));
                 block.and(Rvalue::Cast(CastKind::Misc, source, expr.ty))
             }
+            ExprKind::Use { source } => {
+                let source = unpack!(block = this.as_operand(block, source));
+                block.and(Rvalue::Use(source))
+            }
             ExprKind::ReifyFnPointer { source } => {
                 let source = unpack!(block = this.as_operand(block, source));
                 block.and(Rvalue::Cast(CastKind::ReifyFnPointer, source, expr.ty))

src/librustc_mir/build/expr/category.rs

@@ -68,6 +68,7 @@ impl Category {
             ExprKind::Binary { .. } |
             ExprKind::Box { .. } |
             ExprKind::Cast { .. } |
+            ExprKind::Use { .. } |
             ExprKind::ReifyFnPointer { .. } |
             ExprKind::UnsafeFnPointer { .. } |
             ExprKind::Unsize { .. } |

src/librustc_mir/build/expr/into.rs

@@ -249,6 +249,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             ExprKind::Binary { .. } |
             ExprKind::Box { .. } |
             ExprKind::Cast { .. } |
+            ExprKind::Use { .. } |
             ExprKind::ReifyFnPointer { .. } |
             ExprKind::UnsafeFnPointer { .. } |
             ExprKind::Unsize { .. } |

src/librustc_mir/hair/cx/expr.rs

@@ -602,8 +602,8 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
             // Check to see if this cast is a "coercion cast", where the cast is actually done
             // using a coercion (or is a no-op).
             if let Some(&TyCastKind::CoercionCast) = cx.tcx.cast_kinds.borrow().get(&source.id) {
-                // Skip the actual cast itexpr, as it's now a no-op.
-                return source.make_mirror(cx);
+                // Convert the lexpr to a vexpr.
+                ExprKind::Use { source: source.to_ref() }
             } else {
                 ExprKind::Cast { source: source.to_ref() }
             }