Begin refactor type checking state

This first patch starts by moving around pieces of state related to
type checking. The goal is to slowly unify the type checking state
into a single typing context. This initial patch moves the
ParameterEnvironment into the InferCtxt and moves shared tables
from Inherited and ty::ctxt into their own struct Tables. This
is the foundational work to refactoring the type checker to
enable future evolution of the language and tooling.

Author: jroesch

src/librustc/lib.rs

@@ -61,6 +61,7 @@
 #![feature(str_match_indices)]
 #![feature(vec_push_all)]
 #![feature(wrapping)]
+#![feature(cell_extras)]
 #![cfg_attr(test, feature(test))]
 
 #![allow(trivial_casts)]

src/librustc/middle/astencode.rs

@@ -1027,7 +1027,7 @@ fn encode_side_tables_for_id(ecx: &e::EncodeContext,
         })
     }
 
-    if let Some(item_substs) = tcx.item_substs.borrow().get(&id) {
+    if let Some(item_substs) = tcx.tables.borrow().item_substs.get(&id) {
         rbml_w.tag(c::tag_table_item_subst, |rbml_w| {
             rbml_w.id(id);
             rbml_w.emit_substs(ecx, &item_substs.substs);
@@ -1051,7 +1051,7 @@ fn encode_side_tables_for_id(ecx: &e::EncodeContext,
                     var_id: var_id,
                     closure_expr_id: id
                 };
-                let upvar_capture = tcx.upvar_capture_map.borrow().get(&upvar_id).unwrap().clone();
+                let upvar_capture = tcx.tables.borrow().upvar_capture_map.get(&upvar_id).unwrap().clone();
                 var_id.encode(rbml_w);
                 upvar_capture.encode(rbml_w);
             })
@@ -1074,19 +1074,19 @@ fn encode_side_tables_for_id(ecx: &e::EncodeContext,
     }
 
     let method_call = MethodCall::expr(id);
-    if let Some(method) = tcx.method_map.borrow().get(&method_call) {
+    if let Some(method) = tcx.tables.borrow().method_map.get(&method_call) {
         rbml_w.tag(c::tag_table_method_map, |rbml_w| {
             rbml_w.id(id);
             encode_method_callee(ecx, rbml_w, method_call.autoderef, method)
         })
     }
 
-    if let Some(adjustment) = tcx.adjustments.borrow().get(&id) {
+    if let Some(adjustment) = tcx.tables.borrow().adjustments.get(&id) {
         match *adjustment {
             ty::AdjustDerefRef(ref adj) => {
                 for autoderef in 0..adj.autoderefs {
                     let method_call = MethodCall::autoderef(id, autoderef as u32);
-                    if let Some(method) = tcx.method_map.borrow().get(&method_call) {
+                    if let Some(method) = tcx.tables.borrow().method_map.get(&method_call) {
                         rbml_w.tag(c::tag_table_method_map, |rbml_w| {
                             rbml_w.id(id);
                             encode_method_callee(ecx, rbml_w,
@@ -1104,14 +1104,14 @@ fn encode_side_tables_for_id(ecx: &e::EncodeContext,
         })
     }
 
-    if let Some(closure_type) = tcx.closure_tys.borrow().get(&ast_util::local_def(id)) {
+    if let Some(closure_type) = tcx.tables.borrow().closure_tys.get(&ast_util::local_def(id)) {
         rbml_w.tag(c::tag_table_closure_tys, |rbml_w| {
             rbml_w.id(id);
             rbml_w.emit_closure_type(ecx, closure_type);
         })
     }
 
-    if let Some(closure_kind) = tcx.closure_kinds.borrow().get(&ast_util::local_def(id)) {
+    if let Some(closure_kind) = tcx.tables.borrow().closure_kinds.get(&ast_util::local_def(id)) {
         rbml_w.tag(c::tag_table_closure_kinds, |rbml_w| {
             rbml_w.id(id);
             encode_closure_kind(rbml_w, *closure_kind)
@@ -1630,7 +1630,7 @@ fn decode_side_tables(dcx: &DecodeContext,
                         let item_substs = ty::ItemSubsts {
                             substs: val_dsr.read_substs(dcx)
                         };
-                        dcx.tcx.item_substs.borrow_mut().insert(
+                        dcx.tcx.tables.borrow_mut().item_substs.insert(
                             id, item_substs);
                     }
                     c::tag_table_freevars => {
@@ -1646,7 +1646,7 @@ fn decode_side_tables(dcx: &DecodeContext,
                             closure_expr_id: id
                         };
                         let ub: ty::UpvarCapture = Decodable::decode(val_dsr).unwrap();
-                        dcx.tcx.upvar_capture_map.borrow_mut().insert(upvar_id, ub.tr(dcx));
+                        dcx.tcx.tables.borrow_mut().upvar_capture_map.insert(upvar_id, ub.tr(dcx));
                     }
                     c::tag_table_tcache => {
                         let type_scheme = val_dsr.read_type_scheme(dcx);
@@ -1663,22 +1663,22 @@ fn decode_side_tables(dcx: &DecodeContext,
                             expr_id: id,
                             autoderef: autoderef
                         };
-                        dcx.tcx.method_map.borrow_mut().insert(method_call, method);
+                        dcx.tcx.tables.borrow_mut().method_map.insert(method_call, method);
                     }
                     c::tag_table_adjustments => {
                         let adj: ty::AutoAdjustment = val_dsr.read_auto_adjustment(dcx);
-                        dcx.tcx.adjustments.borrow_mut().insert(id, adj);
+                        dcx.tcx.tables.borrow_mut().adjustments.insert(id, adj);
                     }
                     c::tag_table_closure_tys => {
                         let closure_ty =
                             val_dsr.read_closure_ty(dcx);
-                        dcx.tcx.closure_tys.borrow_mut().insert(ast_util::local_def(id),
+                        dcx.tcx.tables.borrow_mut().closure_tys.insert(ast_util::local_def(id),
                                                                 closure_ty);
                     }
                     c::tag_table_closure_kinds => {
                         let closure_kind =
                             val_dsr.read_closure_kind(dcx);
-                        dcx.tcx.closure_kinds.borrow_mut().insert(ast_util::local_def(id),
+                        dcx.tcx.tables.borrow_mut().closure_kinds.insert(ast_util::local_def(id),
                                                                   closure_kind);
                     }
                     c::tag_table_cast_kinds => {

src/librustc/middle/cfg/construct.rs

@@ -411,7 +411,7 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
             func_or_rcvr: &ast::Expr,
             args: I) -> CFGIndex {
         let method_call = ty::MethodCall::expr(call_expr.id);
-        let fn_ty = match self.tcx.method_map.borrow().get(&method_call) {
+        let fn_ty = match self.tcx.tables.borrow().method_map.get(&method_call) {
             Some(method) => method.ty,
             None => self.tcx.expr_ty_adjusted(func_or_rcvr)
         };
@@ -634,6 +634,6 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
 
     fn is_method_call(&self, expr: &ast::Expr) -> bool {
         let method_call = ty::MethodCall::expr(expr.id);
-        self.tcx.method_map.borrow().contains_key(&method_call)
+        self.tcx.tables.borrow().method_map.contains_key(&method_call)
     }
 }

src/librustc/middle/check_const.rs

@@ -283,12 +283,11 @@ impl<'a, 'tcx> CheckCrateVisitor<'a, 'tcx> {
 
     fn check_static_type(&self, e: &ast::Expr) {
         let ty = self.tcx.node_id_to_type(e.id);
-        let infcx = infer::new_infer_ctxt(self.tcx);
+        let infcx = infer::new_infer_ctxt(self.tcx, None);
         let mut fulfill_cx = traits::FulfillmentContext::new(false);
         let cause = traits::ObligationCause::new(e.span, e.id, traits::SharedStatic);
         fulfill_cx.register_builtin_bound(&infcx, ty, ty::BoundSync, cause);
-        let env = self.tcx.empty_parameter_environment();
-        match fulfill_cx.select_all_or_error(&infcx, &env) {
+        match fulfill_cx.select_all_or_error(&infcx, &infcx.parameter_environment) {
             Ok(()) => { },
             Err(ref errors) => {
                 traits::report_fulfillment_errors(&infcx, errors);
@@ -544,7 +543,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
     match e.node {
         ast::ExprUnary(..) |
         ast::ExprBinary(..) |
-        ast::ExprIndex(..) if v.tcx.method_map.borrow().contains_key(&method_call) => {
+        ast::ExprIndex(..) if v.tcx.tables.borrow().method_map.contains_key(&method_call) => {
             v.add_qualif(ConstQualif::NOT_CONST);
             if v.mode != Mode::Var {
                 span_err!(v.tcx.sess, e.span, E0011,
@@ -695,7 +694,7 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
             }
         }
         ast::ExprMethodCall(..) => {
-            let method_did = match v.tcx.method_map.borrow()[&method_call].origin {
+            let method_did = match v.tcx.tables.borrow().method_map[&method_call].origin {
                 ty::MethodStatic(did) => Some(did),
                 _ => None
             };

src/librustc/middle/check_match.rs

@@ -98,6 +98,7 @@ impl<'a> FromIterator<Vec<&'a Pat>> for Matrix<'a> {
     }
 }
 
+//NOTE: appears to be the only place other then InferCtxt to contain a ParamEnv
 pub struct MatchCheckCtxt<'a, 'tcx: 'a> {
     pub tcx: &'a ty::ctxt<'tcx>,
     pub param_env: ParameterEnvironment<'a, 'tcx>,

src/librustc/middle/const_eval.rs

@@ -1031,10 +1031,9 @@ fn resolve_trait_associated_const<'a, 'tcx: 'a>(tcx: &'a ty::ctxt<'tcx>,
                                               substs: trait_substs });
 
     tcx.populate_implementations_for_trait_if_necessary(trait_ref.def_id());
-    let infcx = infer::new_infer_ctxt(tcx);
+    let infcx = infer::new_infer_ctxt(tcx, None);
 
-    let param_env = tcx.empty_parameter_environment();
-    let mut selcx = traits::SelectionContext::new(&infcx, &param_env);
+    let mut selcx = traits::SelectionContext::new(&infcx, &infcx.parameter_environment);
     let obligation = traits::Obligation::new(traits::ObligationCause::dummy(),
                                              trait_ref.to_poly_trait_predicate());
     let selection = match selcx.select(&obligation) {

src/librustc/middle/dead.rs

@@ -96,7 +96,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
     fn lookup_and_handle_method(&mut self, id: ast::NodeId,
                                 span: codemap::Span) {
         let method_call = ty::MethodCall::expr(id);
-        match self.tcx.method_map.borrow().get(&method_call) {
+        match self.tcx.tables.borrow().method_map.get(&method_call) {
             Some(method) => {
                 match method.origin {
                     ty::MethodStatic(def_id) => {

src/librustc/middle/effect.rs

@@ -140,7 +140,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for EffectCheckVisitor<'a, 'tcx> {
         match expr.node {
             ast::ExprMethodCall(_, _, _) => {
                 let method_call = MethodCall::expr(expr.id);
-                let base_type = self.tcx.method_map.borrow().get(&method_call).unwrap().ty;
+                let base_type = self.tcx.tables.borrow().method_map.get(&method_call).unwrap().ty;
                 debug!("effect: method call case, base type is {:?}",
                         base_type);
                 if type_is_unsafe_function(base_type) {

src/librustc/middle/expr_use_visitor.rs

@@ -257,8 +257,9 @@ impl OverloadedCallType {
     fn from_closure(tcx: &ty::ctxt, closure_did: ast::DefId)
                     -> OverloadedCallType {
         let trait_did =
-            tcx.closure_kinds
+            tcx.tables
                .borrow()
+               .closure_kinds
                .get(&closure_did)
                .expect("OverloadedCallType::from_closure: didn't find closure id")
                .trait_did(tcx);
@@ -787,8 +788,10 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
     // process.
     fn walk_adjustment(&mut self, expr: &ast::Expr) {
         let typer = self.typer;
-        if let Some(adjustment) = typer.adjustments().borrow().get(&expr.id) {
-            match *adjustment {
+        //NOTE(@jroesch): mixed RefCell borrow causes crash
+        let adj = typer.adjustments().get(&expr.id).map(|x| x.clone());
+        if let Some(adjustment) = adj {
+            match adjustment {
                 ty::AdjustReifyFnPointer |
                 ty::AdjustUnsafeFnPointer => {
                     // Creating a closure/fn-pointer or unsizing consumes

src/librustc/middle/infer/mod.rs

@@ -77,6 +77,10 @@ pub struct InferCtxt<'a, 'tcx: 'a> {
 
     // For region variables.
     region_vars: RegionVarBindings<'a, 'tcx>,
+
+    pub parameter_environment: ty::ParameterEnvironment<'a, 'tcx>,
+
+    // pub tables: &'a RefCell<ty::Tables<'tcx>>
 }
 
 /// A map returned by `skolemize_late_bound_regions()` indicating the skolemized
@@ -309,14 +313,16 @@ pub fn fixup_err_to_string(f: fixup_err) -> String {
     }
 }
 
-pub fn new_infer_ctxt<'a, 'tcx>(tcx: &'a ty::ctxt<'tcx>)
+pub fn new_infer_ctxt<'a, 'tcx>(tcx: &'a ty::ctxt<'tcx>,
+                                param_env: Option<ty::ParameterEnvironment<'a, 'tcx>>)
                                 -> InferCtxt<'a, 'tcx> {
     InferCtxt {
         tcx: tcx,
         type_variables: RefCell::new(type_variable::TypeVariableTable::new()),
         int_unification_table: RefCell::new(UnificationTable::new()),
         float_unification_table: RefCell::new(UnificationTable::new()),
         region_vars: RegionVarBindings::new(tcx),
+        parameter_environment: param_env.unwrap_or(tcx.empty_parameter_environment())
     }
 }
 

src/librustc/middle/liveness.rs

@@ -1150,7 +1150,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 
           ast::ExprMethodCall(_, _, ref args) => {
             let method_call = ty::MethodCall::expr(expr.id);
-            let method_ty = self.ir.tcx.method_map.borrow().get(&method_call).unwrap().ty;
+            let method_ty = self.ir.tcx.tables.borrow().method_map.get(&method_call).unwrap().ty;
             let succ = if method_ty.fn_ret().diverges() {
                 self.s.exit_ln
             } else {

src/librustc/middle/mem_categorization.rs

@@ -83,7 +83,7 @@ use syntax::ast::{MutImmutable, MutMutable};
 use syntax::ast;
 use syntax::codemap::Span;
 
-use std::cell::RefCell;
+use std::cell::Ref;
 use std::fmt;
 use std::rc::Rc;
 
@@ -289,7 +289,7 @@ pub trait Typer<'tcx> : ty::ClosureTyper<'tcx> {
     fn node_method_ty(&self, method_call: ty::MethodCall) -> Option<Ty<'tcx>>;
     fn node_method_origin(&self, method_call: ty::MethodCall)
                           -> Option<ty::MethodOrigin<'tcx>>;
-    fn adjustments<'a>(&'a self) -> &'a RefCell<NodeMap<ty::AutoAdjustment<'tcx>>>;
+    fn adjustments(&self) -> Ref<NodeMap<ty::AutoAdjustment<'tcx>>>;
     fn is_method_call(&self, id: ast::NodeId) -> bool;
     fn temporary_scope(&self, rvalue_id: ast::NodeId) -> Option<region::CodeExtent>;
     fn upvar_capture(&self, upvar_id: ty::UpvarId) -> Option<ty::UpvarCapture>;
@@ -408,7 +408,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
         let unadjusted_ty = try!(self.expr_ty(expr));
         Ok(unadjusted_ty.adjust(
             self.tcx(), expr.span, expr.id,
-            self.typer.adjustments().borrow().get(&expr.id),
+            self.typer.adjustments().get(&expr.id),
             |method_call| self.typer.node_method_ty(method_call)))
     }
 
@@ -440,7 +440,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
     }
 
     pub fn cat_expr(&self, expr: &ast::Expr) -> McResult<cmt<'tcx>> {
-        match self.typer.adjustments().borrow().get(&expr.id) {
+        match self.typer.adjustments().get(&expr.id) {
             None => {
                 // No adjustments.
                 self.cat_expr_unadjusted(expr)

src/librustc/middle/reachable.rs

@@ -128,7 +128,7 @@ impl<'a, 'tcx, 'v> Visitor<'v> for ReachableContext<'a, 'tcx> {
             }
             ast::ExprMethodCall(..) => {
                 let method_call = ty::MethodCall::expr(expr.id);
-                match (*self.tcx.method_map.borrow()).get(&method_call).unwrap().origin {
+                match self.tcx.tables.borrow().method_map.get(&method_call).unwrap().origin {
                     ty::MethodStatic(def_id) => {
                         if is_local(def_id) {
                             if self.def_id_represents_local_inlined_item(def_id) {

src/librustc/middle/stability.rs

@@ -406,7 +406,7 @@ pub fn check_expr(tcx: &ty::ctxt, e: &ast::Expr,
         ast::ExprMethodCall(i, _, _) => {
             span = i.span;
             let method_call = ty::MethodCall::expr(e.id);
-            match tcx.method_map.borrow().get(&method_call) {
+            match tcx.tables.borrow().method_map.get(&method_call) {
                 Some(method) => {
                     match method.origin {
                         ty::MethodStatic(def_id) => {

src/librustc/middle/traits/mod.rs

@@ -351,6 +351,7 @@ pub fn type_known_to_meet_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
     }
 }
 
+// TODO: this is gonna need to be removed ...
 /// Normalizes the parameter environment, reporting errors if they occur.
 pub fn normalize_param_env_or_error<'a,'tcx>(unnormalized_env: ty::ParameterEnvironment<'a,'tcx>,
                                              cause: ObligationCause<'tcx>)
@@ -396,13 +397,13 @@ pub fn normalize_param_env_or_error<'a,'tcx>(unnormalized_env: ty::ParameterEnvi
 
     let elaborated_env = unnormalized_env.with_caller_bounds(predicates);
 
-    let infcx = infer::new_infer_ctxt(tcx);
-    let predicates = match fully_normalize(&infcx, &elaborated_env, cause,
-                                           &elaborated_env.caller_bounds) {
+    let infcx = infer::new_infer_ctxt(tcx, Some(elaborated_env));
+    let predicates = match fully_normalize(&infcx, &infcx.parameter_environment, cause,
+                                           &infcx.parameter_environment.caller_bounds) {
         Ok(predicates) => predicates,
         Err(errors) => {
             report_fulfillment_errors(&infcx, &errors);
-            return unnormalized_env; // an unnormalized env is better than nothing
+            return infcx.parameter_environment; // an unnormalized env is better than nothing
         }
     };
 
@@ -420,11 +421,11 @@ pub fn normalize_param_env_or_error<'a,'tcx>(unnormalized_env: ty::ParameterEnvi
             // all things considered.
             let err_msg = fixup_err_to_string(fixup_err);
             tcx.sess.span_err(span, &err_msg);
-            return elaborated_env; // an unnormalized env is better than nothing
+            return infcx.parameter_environment; // an unnormalized env is better than nothing
         }
     };
 
-    elaborated_env.with_caller_bounds(predicates)
+    infcx.parameter_environment.with_caller_bounds(predicates)
 }
 
 pub fn fully_normalize<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,