Address review comments + fix rebase

Author: petrochenkov

src/librustc/middle/mem_categorization.rs

@@ -1105,17 +1105,10 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
 
         (*op)(self, cmt.clone(), pat);
 
-        // This function can be used during region checking when not all paths are fully
-        // resolved. Partially resolved paths in patterns can only legally refer to
-        // associated constants which don't require categorization.
-        let opt_def = if let Some(path_res) = self.tcx().def_map.borrow().get(&pat.id) {
-            if path_res.depth != 0 || path_res.base_def == Def::Err {
-                return Err(());
-            }
-            Some(path_res.full_def())
-        } else {
-            None
-        };
+        let opt_def = self.tcx().expect_def_or_none(pat.id);
+        if opt_def == Some(Def::Err) {
+            return Err(());
+        }
 
         // Note: This goes up here (rather than within the PatKind::TupleStruct arm
         // alone) because struct patterns can refer to struct types or

src/librustc_mir/hair/cx/pattern.rs

@@ -162,7 +162,7 @@ impl<'patcx, 'cx, 'gcx, 'tcx> PatCx<'patcx, 'cx, 'gcx, 'tcx> {
             }
 
             PatKind::Binding(bm, ref ident, ref sub) => {
-                let id = self.cx.tcx.def_map.borrow()[&pat.id].full_def().var_id();
+                let id = self.cx.tcx.expect_def(pat.id).var_id();
                 let var_ty = self.cx.tcx.node_id_to_type(pat.id);
                 let region = match var_ty.sty {
                     ty::TyRef(&r, _) => Some(r),

src/librustc_passes/consts.rs

@@ -584,7 +584,8 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>,
             }
         }
         hir::ExprStruct(..) => {
-            if v.tcx.expect_def(e.id).def_id() == v.tcx.lang_items.unsafe_cell_type().unwrap() {
+            // unsafe_cell_type doesn't necessarily exist with no_core
+            if Some(v.tcx.expect_def(e.id).def_id()) == v.tcx.lang_items.unsafe_cell_type() {
                 v.add_qualif(ConstQualif::MUTABLE_MEM);
             }
         }

src/librustc_resolve/diagnostics.rs

@@ -677,100 +677,6 @@ fn foo<T>(x: T) {} // ok!
 ```
 "##,
 
-E0413: r##"
-A declaration shadows an enum variant or unit-like struct in scope. Example of
-erroneous code:
-
-```compile_fail
-struct Foo;
-
-let Foo = 12i32; // error: declaration of `Foo` shadows an enum variant or
-                 //        unit-like struct in scope
-```
-
-To fix this error, rename the variable such that it doesn't shadow any enum
-variable or structure in scope. Example:
-
-```
-struct Foo;
-
-let foo = 12i32; // ok!
-```
-
-Or:
-
-```
-struct FooStruct;
-
-let Foo = 12i32; // ok!
-```
-
-The goal here is to avoid a conflict of names.
-"##,
-
-E0414: r##"
-A variable binding in an irrefutable pattern is shadowing the name of a
-constant. Example of erroneous code:
-
-```compile_fail
-const FOO: u8 = 7;
-
-let FOO = 5; // error: variable bindings cannot shadow constants
-
-// or
-
-fn bar(FOO: u8) { // error: variable bindings cannot shadow constants
-
-}
-
-// or
-
-for FOO in bar {
-
-}
-```
-
-Introducing a new variable in Rust is done through a pattern. Thus you can have
-`let` bindings like `let (a, b) = ...`. However, patterns also allow constants
-in them, e.g. if you want to match over a constant:
-
-```ignore
-const FOO: u8 = 1;
-
-match (x,y) {
- (3, 4) => { .. }, // it is (3,4)
- (FOO, 1) => { .. }, // it is (1,1)
- (foo, 1) => { .. }, // it is (anything, 1)
-                     // call the value in the first slot "foo"
- _ => { .. } // it is anything
-}
-```
-
-Here, the second arm matches the value of `x` against the constant `FOO`,
-whereas the third arm will accept any value of `x` and call it `foo`.
-
-This works for `match`, however in cases where an irrefutable pattern is
-required, constants can't be used. An irrefutable pattern is one which always
-matches, whose purpose is only to bind variable names to values. These are
-required by let, for, and function argument patterns.
-
-Refutable patterns in such a situation do not make sense, for example:
-
-```ignore
-let Some(x) = foo; // what if foo is None, instead?
-
-let (1, x) = foo; // what if foo.0 is not 1?
-
-let (SOME_CONST, x) = foo; // what if foo.0 is not SOME_CONST?
-
-let SOME_CONST = foo; // what if foo is not SOME_CONST?
-```
-
-Thus, an irrefutable variable binding can't contain a constant.
-
-To fix this error, just give the marked variable a different name.
-"##,
-
 E0415: r##"
 More than one function parameter have the same name. Example of erroneous code:
 
@@ -814,34 +720,6 @@ match (A, B, C) {
 ```
 "##,
 
-E0417: r##"
-A static variable was referenced in a pattern. Example of erroneous code:
-
-```compile_fail
-static FOO : i32 = 0;
-
-match 0 {
-    FOO => {} // error: static variables cannot be referenced in a
-              //        pattern, use a `const` instead
-    _ => {}
-}
-```
-
-The compiler needs to know the value of the pattern at compile time;
-compile-time patterns can defined via const or enum items. Please verify
-that the identifier is spelled correctly, and if so, use a const instead
-of static to define it. Example:
-
-```
-const FOO : i32 = 0;
-
-match 0 {
-    FOO => {} // ok!
-    _ => {}
-}
-```
-"##,
-
 E0422: r##"
 You are trying to use an identifier that is either undefined or not a struct.
 For instance:
@@ -1221,11 +1099,23 @@ impl Foo for i32 {}
 }
 
 register_diagnostics! {
+//  E0153, unused error code
+//  E0157, unused error code
     E0254, // import conflicts with imported crate in this module
+//  E0257,
+//  E0258,
     E0402, // cannot use an outer type parameter in this context
     E0406, // undeclared associated type
-    E0418, // X bindings cannot shadow Ys
-    E0419, // unresolved pattern path kind `name`
-    E0420, // expected pattern path kind, found another pattern path kind
-    E0427, // cannot use `ref` binding mode with ...
+//  E0410, merged into 408
+//  E0413, merged into 530
+//  E0414, merged into 530
+//  E0417, merged into 532
+//  E0418, merged into 532
+//  E0419, merged into 531
+//  E0420, merged into 532
+//  E0421, merged into 531
+    E0530, // X bindings cannot shadow Ys
+    E0531, // unresolved pattern path kind `name`
+    E0532, // expected pattern path kind, found another pattern path kind
+//  E0427, merged into 530
 }

src/librustc_resolve/lib.rs

@@ -155,11 +155,11 @@ enum ResolutionError<'a> {
     CannotCaptureDynamicEnvironmentInFnItem,
     /// error E0435: attempt to use a non-constant value in a constant
     AttemptToUseNonConstantValueInConstant,
-    /// error E0418: X bindings cannot shadow Ys
+    /// error E0530: X bindings cannot shadow Ys
     BindingShadowsSomethingUnacceptable(&'a str, &'a str, Name),
-    /// error E0419: unresolved pattern path kind `name`
+    /// error E0531: unresolved pattern path kind `name`
     PatPathUnresolved(&'a str, &'a Path),
-    /// error E0420: expected pattern path kind, found another pattern path kind
+    /// error E0532: expected pattern path kind, found another pattern path kind
     PatPathUnexpected(&'a str, &'a str, &'a Path),
 }
 
@@ -426,11 +426,10 @@ fn resolve_struct_error<'b, 'a: 'b, 'c>(resolver: &'b Resolver<'a>,
         ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, shadows_what, name) => {
             let mut err = struct_span_err!(resolver.session,
                                            span,
-                                           E0418,
+                                           E0530,
                                            "{}s cannot shadow {}s", what_binding, shadows_what);
             err.span_label(span, &format!("cannot be named the same as a {}", shadows_what));
-            if let Some(binding) = resolver.current_module
-                                           .resolve_name_in_lexical_scope(name, ValueNS) {
+            if let Success(binding) = resolver.current_module.resolve_name(name, ValueNS, true) {
                 let participle = if binding.is_import() { "imported" } else { "defined" };
                 err.span_label(binding.span, &format!("a {} `{}` is {} here",
                                                       shadows_what, name, participle));
@@ -440,15 +439,15 @@ fn resolve_struct_error<'b, 'a: 'b, 'c>(resolver: &'b Resolver<'a>,
         ResolutionError::PatPathUnresolved(expected_what, path) => {
             struct_span_err!(resolver.session,
                              span,
-                             E0419,
+                             E0531,
                              "unresolved {} `{}`",
                              expected_what,
                              path.segments.last().unwrap().identifier)
         }
         ResolutionError::PatPathUnexpected(expected_what, found_what, path) => {
             struct_span_err!(resolver.session,
                              span,
-                             E0420,
+                             E0532,
                              "expected {}, found {} `{}`",
                              expected_what,
                              found_what,
@@ -2201,15 +2200,15 @@ impl<'a> Resolver<'a> {
                      pat_id: NodeId,
                      outer_pat_id: NodeId,
                      pat_src: PatternSource,
-                     bindings_list: &mut HashMap<Name, NodeId>)
+                     bindings: &mut HashMap<Name, NodeId>)
                      -> PathResolution {
         // Add the binding to the local ribs, if it
-        // doesn't already exist in the bindings list. (We
-        // must not add it if it's in the bindings list
+        // doesn't already exist in the bindings map. (We
+        // must not add it if it's in the bindings map
         // because that breaks the assumptions later
         // passes make about or-patterns.)
         let renamed = mtwt::resolve(ident.node);
-        let def = match bindings_list.get(&renamed).cloned() {
+        let def = match bindings.get(&renamed).cloned() {
             Some(id) if id == outer_pat_id => {
                 // `Variant(a, a)`, error
                 resolve_error(
@@ -2231,8 +2230,9 @@ impl<'a> Resolver<'a> {
                 Def::Err
             }
             Some(..) if pat_src == PatternSource::Match => {
-                // `Varian1(a) | Varian2(a)`, ok
-                Def::Local(self.definitions.local_def_id(pat_id), pat_id)
+                // `Variant1(a) | Variant2(a)`, ok
+                // Reuse definition from the first `a`.
+                self.value_ribs.last_mut().unwrap().bindings[&renamed]
             }
             Some(..) => {
                 span_bug!(ident.span, "two bindings with the same name from \
@@ -2244,7 +2244,7 @@ impl<'a> Resolver<'a> {
                 // define `Invalid` bindings as `Def::Local`, just don't add them to the lists.
                 let def = Def::Local(self.definitions.local_def_id(pat_id), pat_id);
                 if ident.node.name != keywords::Invalid.name() {
-                    bindings_list.insert(renamed, outer_pat_id);
+                    bindings.insert(renamed, outer_pat_id);
                     self.value_ribs.last_mut().unwrap().bindings.insert(renamed, def);
                 }
                 def
@@ -2255,12 +2255,12 @@ impl<'a> Resolver<'a> {
     }
 
     fn resolve_pattern_path<ExpectedFn>(&mut self,
-                            pat_id: NodeId,
-                            qself: Option<&QSelf>,
-                            path: &Path,
-                            namespace: Namespace,
-                            expected_fn: ExpectedFn,
-                            expected_what: &'static str)
+                                        pat_id: NodeId,
+                                        qself: Option<&QSelf>,
+                                        path: &Path,
+                                        namespace: Namespace,
+                                        expected_fn: ExpectedFn,
+                                        expected_what: &str)
         where ExpectedFn: FnOnce(Def) -> bool
     {
         let resolution = if let Some(resolution) = self.resolve_possibly_assoc_item(pat_id,
@@ -2307,8 +2307,8 @@ impl<'a> Resolver<'a> {
                        pat_src: PatternSource,
                        // Maps idents to the node ID for the
                        // outermost pattern that binds them.
-                       bindings_list: &mut HashMap<Name, NodeId>) {
-        // Visit all direct subpatterns of this pattern with the same PatternBindingMode.
+                       bindings: &mut HashMap<Name, NodeId>) {
+        // Visit all direct subpatterns of this pattern.
         let outer_pat_id = pat.id;
         pat.walk(&mut |pat| {
             match pat.node {
@@ -2340,7 +2340,7 @@ impl<'a> Resolver<'a> {
                                 // These entities are explicitly allowed
                                 // to be shadowed by fresh bindings.
                                 self.fresh_binding(ident, pat.id, outer_pat_id,
-                                                   pat_src, bindings_list)
+                                                   pat_src, bindings)
                             }
                             def => {
                                 span_bug!(ident.span, "unexpected definition for an \
@@ -2349,7 +2349,7 @@ impl<'a> Resolver<'a> {
                         }
                     } else {
                         // Fall back to a fresh binding.
-                        self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings_list)
+                        self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
                     };
 
                     self.record_def(pat.id, resolution);

src/librustc_typeck/check/_match.rs

@@ -151,7 +151,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 // is good enough.
                 self.demand_suptype(pat.span, expected, const_ty);
             }
-            PatKind::Binding(bm, ref path, ref sub) => {
+            PatKind::Binding(bm, _, ref sub) => {
                 let typ = self.local_ty(pat.span, pat.id);
                 match bm {
                     hir::BindByRef(mutbl) => {
@@ -180,7 +180,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
                 // if there are multiple arms, make sure they all agree on
                 // what the type of the binding `x` ought to be
-                match tcx.def_map.borrow()[&pat.id].full_def() {
+                match tcx.expect_def(pat.id) {
                     Def::Err => {}
                     Def::Local(_, var_id) => {
                         if var_id != pat.id {

src/librustc_typeck/check/mod.rs

@@ -86,8 +86,8 @@ use fmt_macros::{Parser, Piece, Position};
 use middle::cstore::LOCAL_CRATE;
 use hir::def::{self, Def};
 use hir::def_id::DefId;
+use hir::pat_util;
 use rustc::infer::{self, InferCtxt, InferOk, TypeOrigin, TypeTrace, type_variable};
-use hir::pat_util::{self};
 use rustc::ty::subst::{self, Subst, Substs, VecPerParamSpace, ParamSpace};
 use rustc::traits::{self, ProjectionMode};
 use rustc::ty::{GenericPredicates, TypeScheme};