Auto merge of #43710 - zackmdavis:field_init_shorthand_power_slam, r=Mark-Simulacrum

[rust.git] / src / librustc_typeck / check / autoderef.rs

diff --git a/src/librustc_typeck/check/autoderef.rs b/src/librustc_typeck/check/autoderef.rs
index 098674519b4d804beefa82fbd8bf074c5651d907..e0e946a9c63fa7b367a5ef37c80da9ee7de024b0 100644 (file)
--- a/src/librustc_typeck/check/autoderef.rs
+++ b/src/librustc_typeck/check/autoderef.rs
@@ -11,17 +11,20 @@
 use astconv::AstConv;
 
 use super::{FnCtxt, LvalueOp};
+use super::method::MethodCallee;
 
 use rustc::infer::InferOk;
 use rustc::traits;
 use rustc::ty::{self, Ty, TraitRef};
 use rustc::ty::{ToPredicate, TypeFoldable};
 use rustc::ty::{LvaluePreference, NoPreference};
-use rustc::ty::adjustment::AutoBorrow;
+use rustc::ty::adjustment::{Adjustment, Adjust, OverloadedDeref};
 
 use syntax_pos::Span;
 use syntax::symbol::Symbol;
 
+use std::iter;
+
 #[derive(Copy, Clone, Debug)]
 enum AutoderefKind {
     Builtin,
@@ -115,17 +118,21 @@ fn overloaded_deref_ty(&mut self, ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
         let cause = traits::ObligationCause::misc(self.span, self.fcx.body_id);
 
         let mut selcx = traits::SelectionContext::new(self.fcx);
-        let obligation = traits::Obligation::new(cause.clone(), trait_ref.to_predicate());
+        let obligation = traits::Obligation::new(cause.clone(),
+                                                 self.fcx.param_env,
+                                                 trait_ref.to_predicate());
         if !selcx.evaluate_obligation(&obligation) {
             debug!("overloaded_deref_ty: cannot match obligation");
             return None;
         }
 
         let normalized = traits::normalize_projection_type(&mut selcx,
-                                                           ty::ProjectionTy {
-                                                               trait_ref: trait_ref,
-                                                               item_name: Symbol::intern("Target"),
-                                                           },
+                                                           self.fcx.param_env,
+                                                           ty::ProjectionTy::from_ref_and_name(
+                                                               tcx,
+                                                               trait_ref,
+                                                               Symbol::intern("Target"),
+                                                           ),
                                                            cause,
                                                            0);
 
@@ -151,25 +158,39 @@ pub fn step_count(&self) -> usize {
         self.steps.len()
     }
 
-    /// Returns the steps required in adjustments (overloaded deref calls).
+    /// Returns the adjustment steps.
     pub fn adjust_steps(&self, pref: LvaluePreference)
-                        -> Vec<Option<ty::MethodCallee<'tcx>>> {
+                        -> Vec<Adjustment<'tcx>> {
         self.fcx.register_infer_ok_obligations(self.adjust_steps_as_infer_ok(pref))
     }
 
     pub fn adjust_steps_as_infer_ok(&self, pref: LvaluePreference)
-                                    -> InferOk<'tcx, Vec<Option<ty::MethodCallee<'tcx>>>> {
+                                    -> InferOk<'tcx, Vec<Adjustment<'tcx>>> {
         let mut obligations = vec![];
-        let steps: Vec<_> = self.steps.iter().map(|&(ty, kind)| {
+        let targets = self.steps.iter().skip(1).map(|&(ty, _)| ty)
+            .chain(iter::once(self.cur_ty));
+        let steps: Vec<_> = self.steps.iter().map(|&(source, kind)| {
             if let AutoderefKind::Overloaded = kind {
-                self.fcx.try_overloaded_deref(self.span, ty, pref)
-                    .map(|InferOk { value: (_, method), obligations: o }| {
+                self.fcx.try_overloaded_deref(self.span, source, pref)
+                    .and_then(|InferOk { value: method, obligations: o }| {
                         obligations.extend(o);
-                        method
+                        if let ty::TyRef(region, mt) = method.sig.output().sty {
+                            Some(OverloadedDeref {
+                                region,
+                                mutbl: mt.mutbl,
+                            })
+                        } else {
+                            None
+                        }
                     })
             } else {
                 None
             }
+        }).zip(targets).map(|(autoderef, target)| {
+            Adjustment {
+                kind: Adjust::Deref(autoderef),
+                target
+            }
         }).collect();
 
         InferOk {
@@ -196,7 +217,7 @@ pub fn autoderef(&'a self, span: Span, base_ty: Ty<'tcx>) -> Autoderef<'a, 'gcx,
             cur_ty: self.resolve_type_vars_if_possible(&base_ty),
             obligations: vec![],
             at_start: true,
-            span: span,
+            span,
         }
     }
 
@@ -204,9 +225,7 @@ pub fn try_overloaded_deref(&self,
                                 span: Span,
                                 base_ty: Ty<'tcx>,
                                 pref: LvaluePreference)
-                                -> Option<InferOk<'tcx,
-                                    (Option<AutoBorrow<'tcx>>,
-                                     ty::MethodCallee<'tcx>)>> {
+                                -> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
         self.try_overloaded_lvalue_op(span, base_ty, &[], pref, LvalueOp::Deref)
     }
 }