Rollup merge of rust-lang#37408 - eddyb:lazy-5, r=nikomatsakis

[5/n] rustc: record the target type of every adjustment.

_This is part of a series ([prev](rust-lang#37404) | [next](rust-lang#37412)) of patches designed to rework rustc into an out-of-order on-demand pipeline model for both better feature support (e.g. [MIR-based](https://github.com/solson/miri) early constant evaluation) and incremental execution of compiler passes (e.g. type-checking), with beneficial consequences to IDE support as well.
If any motivation is unclear, please ask for additional PR description clarifications or code comments._

<hr>

The first commit rearranges `tcx.tables` so that all users go through `tcx.tables()`. This in preparation for per-body `Tables` where they will be requested for a specific `DefId`. Included to minimize churn.

The rest of the changes focus on adjustments, there are some renamings, but the main addition is the target type, always available in all cases (as opposed to just for unsizing where it was previously needed).

Possibly the most significant effect of this change is that figuring out the final type of an expression is now _always_ just one successful `HashMap` lookup (either the adjustment or, if that doesn't exist, the node type).

src/librustc/cfg/construct.rs

@@ -311,11 +311,11 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
             }
 
             hir::ExprIndex(ref l, ref r) |
-            hir::ExprBinary(_, ref l, ref r) if self.tcx.is_method_call(expr.id) => {
+            hir::ExprBinary(_, ref l, ref r) if self.tcx.tables().is_method_call(expr.id) => {
                 self.call(expr, pred, &l, Some(&**r).into_iter())
             }
 
-            hir::ExprUnary(_, ref e) if self.tcx.is_method_call(expr.id) => {
+            hir::ExprUnary(_, ref e) if self.tcx.tables().is_method_call(expr.id) => {
                 self.call(expr, pred, &e, None::<hir::Expr>.iter())
             }
 
@@ -372,9 +372,9 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
             func_or_rcvr: &hir::Expr,
             args: I) -> CFGIndex {
         let method_call = ty::MethodCall::expr(call_expr.id);
-        let fn_ty = match self.tcx.tables.borrow().method_map.get(&method_call) {
+        let fn_ty = match self.tcx.tables().method_map.get(&method_call) {
             Some(method) => method.ty,
-            None => self.tcx.expr_ty_adjusted(func_or_rcvr)
+            None => self.tcx.tables().expr_ty_adjusted(func_or_rcvr)
         };
 
         let func_or_rcvr_exit = self.expr(func_or_rcvr, pred);

src/librustc/infer/mod.rs

@@ -1266,26 +1266,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         self.region_vars.new_bound(debruijn)
     }
 
-    /// Apply `adjustment` to the type of `expr`
-    pub fn adjust_expr_ty(&self,
-                          expr: &hir::Expr,
-                          adjustment: Option<&adjustment::AutoAdjustment<'tcx>>)
-                          -> Ty<'tcx>
-    {
-        let raw_ty = self.expr_ty(expr);
-        let raw_ty = self.shallow_resolve(raw_ty);
-        let resolve_ty = |ty: Ty<'tcx>| self.resolve_type_vars_if_possible(&ty);
-        raw_ty.adjust(self.tcx,
-                      expr.span,
-                      expr.id,
-                      adjustment,
-                      |method_call| self.tables
-                                        .borrow()
-                                        .method_map
-                                        .get(&method_call)
-                                        .map(|method| resolve_ty(method.ty)))
-    }
-
     /// True if errors have been reported since this infcx was
     /// created.  This is sometimes used as a heuristic to skip
     /// reporting errors that often occur as a result of earlier
@@ -1622,7 +1602,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 
     pub fn expr_ty_adjusted(&self, expr: &hir::Expr) -> McResult<Ty<'tcx>> {
-        let ty = self.adjust_expr_ty(expr, self.tables.borrow().adjustments.get(&expr.id));
+        let ty = self.tables.borrow().expr_ty_adjusted(expr);
         self.resolve_type_vars_or_error(&ty)
     }
 
@@ -1666,9 +1646,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             .map(|method| method.def_id)
     }
 
-    pub fn adjustments(&self) -> Ref<NodeMap<adjustment::AutoAdjustment<'tcx>>> {
+    pub fn adjustments(&self) -> Ref<NodeMap<adjustment::Adjustment<'tcx>>> {
         fn project_adjustments<'a, 'tcx>(tables: &'a ty::Tables<'tcx>)
-                                        -> &'a NodeMap<adjustment::AutoAdjustment<'tcx>> {
+                                        -> &'a NodeMap<adjustment::Adjustment<'tcx>> {
             &tables.adjustments
         }
 

src/librustc/middle/dead.rs

@@ -92,7 +92,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
         match def {
             Def::AssociatedTy(..) | Def::Method(_) | Def::AssociatedConst(_)
             if self.tcx.trait_of_item(def.def_id()).is_some() => {
-                if let Some(substs) = self.tcx.tables.borrow().item_substs.get(&id) {
+                if let Some(substs) = self.tcx.tables().item_substs.get(&id) {
                     if let ty::TyAdt(tyid, _) = substs.substs.type_at(0).sty {
                         self.check_def_id(tyid.did);
                     }
@@ -123,12 +123,12 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
 
     fn lookup_and_handle_method(&mut self, id: ast::NodeId) {
         let method_call = ty::MethodCall::expr(id);
-        let method = self.tcx.tables.borrow().method_map[&method_call];
+        let method = self.tcx.tables().method_map[&method_call];
         self.check_def_id(method.def_id);
     }
 
     fn handle_field_access(&mut self, lhs: &hir::Expr, name: ast::Name) {
-        match self.tcx.expr_ty_adjusted(lhs).sty {
+        match self.tcx.tables().expr_ty_adjusted(lhs).sty {
             ty::TyAdt(def, _) => {
                 self.insert_def_id(def.struct_variant().field_named(name).did);
             }
@@ -137,7 +137,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
     }
 
     fn handle_tup_field_access(&mut self, lhs: &hir::Expr, idx: usize) {
-        match self.tcx.expr_ty_adjusted(lhs).sty {
+        match self.tcx.tables().expr_ty_adjusted(lhs).sty {
             ty::TyAdt(def, _) => {
                 self.insert_def_id(def.struct_variant().fields[idx].did);
             }
@@ -148,7 +148,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
 
     fn handle_field_pattern_match(&mut self, lhs: &hir::Pat,
                                   pats: &[codemap::Spanned<hir::FieldPat>]) {
-        let variant = match self.tcx.node_id_to_type(lhs.id).sty {
+        let variant = match self.tcx.tables().node_id_to_type(lhs.id).sty {
             ty::TyAdt(adt, _) => {
                 adt.variant_of_def(self.tcx.expect_def(lhs.id))
             }
@@ -433,7 +433,7 @@ impl<'a, 'tcx> DeadVisitor<'a, 'tcx> {
     }
 
     fn should_warn_about_field(&mut self, field: &hir::StructField) -> bool {
-        let field_type = self.tcx.node_id_to_type(field.id);
+        let field_type = self.tcx.tables().node_id_to_type(field.id);
         let is_marker_field = match field_type.ty_to_def_id() {
             Some(def_id) => self.tcx.lang_items.items().iter().any(|item| *item == Some(def_id)),
             _ => false

src/librustc/middle/effect.rs

@@ -159,7 +159,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for EffectCheckVisitor<'a, 'tcx> {
         match expr.node {
             hir::ExprMethodCall(..) => {
                 let method_call = MethodCall::expr(expr.id);
-                let base_type = self.tcx.tables.borrow().method_map[&method_call].ty;
+                let base_type = self.tcx.tables().method_map[&method_call].ty;
                 debug!("effect: method call case, base type is {:?}",
                         base_type);
                 if type_is_unsafe_function(base_type) {
@@ -168,15 +168,15 @@ impl<'a, 'tcx, 'v> Visitor<'v> for EffectCheckVisitor<'a, 'tcx> {
                 }
             }
             hir::ExprCall(ref base, _) => {
-                let base_type = self.tcx.expr_ty_adjusted(base);
+                let base_type = self.tcx.tables().expr_ty_adjusted(base);
                 debug!("effect: call case, base type is {:?}",
                         base_type);
                 if type_is_unsafe_function(base_type) {
                     self.require_unsafe(expr.span, "call to unsafe function")
                 }
             }
             hir::ExprUnary(hir::UnDeref, ref base) => {
-                let base_type = self.tcx.expr_ty_adjusted(base);
+                let base_type = self.tcx.tables().expr_ty_adjusted(base);
                 debug!("effect: unary case, base type is {:?}",
                         base_type);
                 if let ty::TyRawPtr(_) = base_type.sty {
@@ -200,7 +200,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for EffectCheckVisitor<'a, 'tcx> {
                 }
             }
             hir::ExprField(ref base_expr, field) => {
-                if let ty::TyAdt(adt, ..) = self.tcx.expr_ty_adjusted(base_expr).sty {
+                if let ty::TyAdt(adt, ..) = self.tcx.tables().expr_ty_adjusted(base_expr).sty {
                     if adt.is_union() {
                         self.require_unsafe(field.span, "access to union field");
                     }
@@ -214,7 +214,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for EffectCheckVisitor<'a, 'tcx> {
 
     fn visit_pat(&mut self, pat: &hir::Pat) {
         if let PatKind::Struct(_, ref fields, _) = pat.node {
-            if let ty::TyAdt(adt, ..) = self.tcx.pat_ty(pat).sty {
+            if let ty::TyAdt(adt, ..) = self.tcx.tables().pat_ty(pat).sty {
                 if adt.is_union() {
                     for field in fields {
                         self.require_unsafe(field.span, "matching on union field");

src/librustc/middle/expr_use_visitor.rs

@@ -720,20 +720,33 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
         //NOTE(@jroesch): mixed RefCell borrow causes crash
         let adj = infcx.adjustments().get(&expr.id).map(|x| x.clone());
         if let Some(adjustment) = adj {
-            match adjustment {
-                adjustment::AdjustNeverToAny(..) |
-                adjustment::AdjustReifyFnPointer |
-                adjustment::AdjustUnsafeFnPointer |
-                adjustment::AdjustMutToConstPointer => {
+            match adjustment.kind {
+                adjustment::Adjust::NeverToAny |
+                adjustment::Adjust::ReifyFnPointer |
+                adjustment::Adjust::UnsafeFnPointer |
+                adjustment::Adjust::MutToConstPointer => {
                     // Creating a closure/fn-pointer or unsizing consumes
                     // the input and stores it into the resulting rvalue.
                     debug!("walk_adjustment: trivial adjustment");
                     let cmt_unadjusted =
                         return_if_err!(self.mc.cat_expr_unadjusted(expr));
                     self.delegate_consume(expr.id, expr.span, cmt_unadjusted);
                 }
-                adjustment::AdjustDerefRef(ref adj) => {
-                    self.walk_autoderefref(expr, adj);
+                adjustment::Adjust::DerefRef { autoderefs, autoref, unsize } => {
+                    debug!("walk_adjustment expr={:?} adj={:?}", expr, adjustment);
+
+                    self.walk_autoderefs(expr, autoderefs);
+
+                    let cmt_derefd =
+                        return_if_err!(self.mc.cat_expr_autoderefd(expr, autoderefs));
+
+                    let cmt_refd =
+                        self.walk_autoref(expr, cmt_derefd, autoref);
+
+                    if unsize {
+                        // Unsizing consumes the thin pointer and produces a fat one.
+                        self.delegate_consume(expr.id, expr.span, cmt_refd);
+                    }
                 }
             }
         }
@@ -770,28 +783,6 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
         }
     }
 
-    fn walk_autoderefref(&mut self,
-                         expr: &hir::Expr,
-                         adj: &adjustment::AutoDerefRef<'tcx>) {
-        debug!("walk_autoderefref expr={:?} adj={:?}",
-               expr,
-               adj);
-
-        self.walk_autoderefs(expr, adj.autoderefs);
-
-        let cmt_derefd =
-            return_if_err!(self.mc.cat_expr_autoderefd(expr, adj.autoderefs));
-
-        let cmt_refd =
-            self.walk_autoref(expr, cmt_derefd, adj.autoref);
-
-        if adj.unsize.is_some() {
-            // Unsizing consumes the thin pointer and produces a fat one.
-            self.delegate_consume(expr.id, expr.span, cmt_refd);
-        }
-    }
-
-
     /// Walks the autoref `opt_autoref` applied to the autoderef'd
     /// `expr`. `cmt_derefd` is the mem-categorized form of `expr`
     /// after all relevant autoderefs have occurred. Because AutoRefs
@@ -803,7 +794,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
     fn walk_autoref(&mut self,
                     expr: &hir::Expr,
                     cmt_base: mc::cmt<'tcx>,
-                    opt_autoref: Option<adjustment::AutoRef<'tcx>>)
+                    opt_autoref: Option<adjustment::AutoBorrow<'tcx>>)
                     -> mc::cmt<'tcx>
     {
         debug!("walk_autoref(expr.id={} cmt_derefd={:?} opt_autoref={:?})",
@@ -822,7 +813,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
         };
 
         match *autoref {
-            adjustment::AutoPtr(r, m) => {
+            adjustment::AutoBorrow::Ref(r, m) => {
                 self.delegate.borrow(expr.id,
                                      expr.span,
                                      cmt_base,
@@ -831,7 +822,7 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
                                      AutoRef);
             }
 
-            adjustment::AutoUnsafe(m) => {
+            adjustment::AutoBorrow::RawPtr(m) => {
                 debug!("walk_autoref: expr.id={} cmt_base={:?}",
                        expr.id,
                        cmt_base);

src/librustc/middle/intrinsicck.rs

@@ -163,7 +163,7 @@ impl<'a, 'gcx, 'tcx, 'v> Visitor<'v> for ExprVisitor<'a, 'gcx, 'tcx> {
         if let hir::ExprPath(..) = expr.node {
             match self.infcx.tcx.expect_def(expr.id) {
                 Def::Fn(did) if self.def_id_is_transmute(did) => {
-                    let typ = self.infcx.tcx.node_id_to_type(expr.id);
+                    let typ = self.infcx.tcx.tables().node_id_to_type(expr.id);
                     match typ.sty {
                         ty::TyFnDef(.., ref bare_fn_ty) if bare_fn_ty.abi == RustIntrinsic => {
                             let from = bare_fn_ty.sig.0.inputs[0];

src/librustc/middle/liveness.rs

@@ -1081,7 +1081,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 
           hir::ExprAssignOp(_, ref l, ref r) => {
             // an overloaded assign op is like a method call
-            if self.ir.tcx.is_method_call(expr.id) {
+            if self.ir.tcx.tables().is_method_call(expr.id) {
                 let succ = self.propagate_through_expr(&l, succ);
                 self.propagate_through_expr(&r, succ)
             } else {
@@ -1113,8 +1113,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 
           hir::ExprCall(ref f, ref args) => {
             // FIXME(canndrew): This is_never should really be an is_uninhabited
-            let diverges = !self.ir.tcx.is_method_call(expr.id) &&
-                self.ir.tcx.expr_ty_adjusted(&f).fn_ret().0.is_never();
+            let diverges = !self.ir.tcx.tables().is_method_call(expr.id) &&
+                self.ir.tcx.tables().expr_ty_adjusted(&f).fn_ret().0.is_never();
             let succ = if diverges {
                 self.s.exit_ln
             } else {
@@ -1126,7 +1126,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 
           hir::ExprMethodCall(.., ref args) => {
             let method_call = ty::MethodCall::expr(expr.id);
-            let method_ty = self.ir.tcx.tables.borrow().method_map[&method_call].ty;
+            let method_ty = self.ir.tcx.tables().method_map[&method_call].ty;
             // FIXME(canndrew): This is_never should really be an is_uninhabited
             let succ = if method_ty.fn_ret().0.is_never() {
                 self.s.exit_ln
@@ -1409,7 +1409,7 @@ fn check_expr(this: &mut Liveness, expr: &Expr) {
       }
 
       hir::ExprAssignOp(_, ref l, _) => {
-        if !this.ir.tcx.is_method_call(expr.id) {
+        if !this.ir.tcx.tables().is_method_call(expr.id) {
             this.check_lvalue(&l);
         }
 
@@ -1459,7 +1459,7 @@ fn check_fn(_v: &Liveness,
 
 impl<'a, 'tcx> Liveness<'a, 'tcx> {
     fn fn_ret(&self, id: NodeId) -> ty::Binder<Ty<'tcx>> {
-        let fn_ty = self.ir.tcx.node_id_to_type(id);
+        let fn_ty = self.ir.tcx.tables().node_id_to_type(id);
         match fn_ty.sty {
             ty::TyClosure(closure_def_id, substs) =>
                 self.ir.tcx.closure_type(closure_def_id, substs).sig.output(),
@@ -1502,7 +1502,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                     None if !body.stmts.is_empty() =>
                         match body.stmts.last().unwrap().node {
                             hir::StmtSemi(ref e, _) => {
-                                self.ir.tcx.expr_ty(&e) == fn_ret
+                                self.ir.tcx.tables().expr_ty(&e) == fn_ret
                             },
                             _ => false
                         },

src/librustc/middle/mem_categorization.rs

@@ -354,11 +354,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
     }
 
     fn expr_ty_adjusted(&self, expr: &hir::Expr) -> McResult<Ty<'tcx>> {
-        let unadjusted_ty = self.expr_ty(expr)?;
-        Ok(unadjusted_ty.adjust(
-            self.tcx(), expr.span, expr.id,
-            self.infcx.adjustments().get(&expr.id),
-            |method_call| self.infcx.node_method_ty(method_call)))
+        self.infcx.expr_ty_adjusted(expr)
     }
 
     fn node_ty(&self, id: ast::NodeId) -> McResult<Ty<'tcx>> {
@@ -396,19 +392,21 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
             }
 
             Some(adjustment) => {
-                match *adjustment {
-                    adjustment::AdjustDerefRef(
-                        adjustment::AutoDerefRef {
-                            autoref: None, unsize: None, autoderefs, ..}) => {
+                match adjustment.kind {
+                    adjustment::Adjust::DerefRef {
+                        autoderefs,
+                        autoref: None,
+                        unsize: false
+                    } => {
                         // Equivalent to *expr or something similar.
                         self.cat_expr_autoderefd(expr, autoderefs)
                     }
 
-                    adjustment::AdjustNeverToAny(..) |
-                    adjustment::AdjustReifyFnPointer |
-                    adjustment::AdjustUnsafeFnPointer |
-                    adjustment::AdjustMutToConstPointer |
-                    adjustment::AdjustDerefRef(_) => {
+                    adjustment::Adjust::NeverToAny |
+                    adjustment::Adjust::ReifyFnPointer |
+                    adjustment::Adjust::UnsafeFnPointer |
+                    adjustment::Adjust::MutToConstPointer |
+                    adjustment::Adjust::DerefRef {..} => {
                         debug!("cat_expr({:?}): {:?}",
                                adjustment,
                                expr);

src/librustc/middle/reachable.rs

@@ -116,7 +116,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for ReachableContext<'a, 'tcx> {
             }
             hir::ExprMethodCall(..) => {
                 let method_call = ty::MethodCall::expr(expr.id);
-                let def_id = self.tcx.tables.borrow().method_map[&method_call].def_id;
+                let def_id = self.tcx.tables().method_map[&method_call].def_id;
 
                 // Mark the trait item (and, possibly, its default impl) as reachable
                 // Or mark inherent impl item as reachable