auto merge of #10026 : luqmana/rust/mut-pat, r=pcwalton

Fixes #9792.

Author: bors

src/librustc/middle/borrowck/gather_loans/mod.rs

@@ -730,7 +730,7 @@ impl<'self> GatherLoanCtxt<'self> {
                                          loan_mutability,
                                          scope_r);
                   }
-                  ast::BindInfer => {
+                  ast::BindByValue(_) => {
                       // No borrows here, but there may be moves
                       if self.bccx.is_move(pat.id) {
                           gather_moves::gather_move_from_pat(

src/librustc/middle/check_match.rs

@@ -884,7 +884,7 @@ fn check_legality_of_move_bindings(cx: &MatchCheckCtxt,
                 BindByRef(_) => {
                     by_ref_span = Some(span);
                 }
-                BindInfer => {
+                BindByValue(_) => {
                     if cx.moves_map.contains(&id) {
                         any_by_move = true;
                     }

src/librustc/middle/kind.rs

@@ -432,14 +432,12 @@ fn is_nullary_variant(cx: &Context, ex: @Expr) -> bool {
 
 fn check_imm_free_var(cx: &Context, def: Def, sp: Span) {
     match def {
-        DefLocal(_, is_mutbl) => {
-            if is_mutbl {
-                cx.tcx.sess.span_err(
-                    sp,
-                    "mutable variables cannot be implicitly captured");
-            }
+        DefLocal(_, BindByValue(MutMutable)) => {
+            cx.tcx.sess.span_err(
+                sp,
+                "mutable variables cannot be implicitly captured");
         }
-        DefArg(*) => { /* ok */ }
+        DefLocal(*) | DefArg(*) => { /* ok */ }
         DefUpvar(_, def1, _, _) => { check_imm_free_var(cx, *def1, sp); }
         DefBinding(*) | DefSelf(*) => { /*ok*/ }
         _ => {

src/librustc/middle/lint.rs

@@ -813,27 +813,24 @@ fn check_unused_unsafe(cx: &Context, e: &ast::Expr) {
 }
 
 fn check_unused_mut_pat(cx: &Context, p: @ast::Pat) {
-    let mut used = false;
-    let mut bindings = 0;
-    do pat_util::pat_bindings(cx.tcx.def_map, p) |_, id, _, _| {
-        used = used || cx.tcx.used_mut_nodes.contains(&id);
-        bindings += 1;
-    }
-    if !used {
-        let msg = if bindings == 1 {
-            "variable does not need to be mutable"
-        } else {
-            "variables do not need to be mutable"
-        };
-        cx.span_lint(unused_mut, p.span, msg);
-    }
-}
-
-fn check_unused_mut_fn_decl(cx: &Context, fd: &ast::fn_decl) {
-    for arg in fd.inputs.iter() {
-        if arg.is_mutbl {
-            check_unused_mut_pat(cx, arg.pat);
+    match p.node {
+        ast::PatIdent(ast::BindByValue(ast::MutMutable), _, _) => {
+            let mut used = false;
+            let mut bindings = 0;
+            do pat_util::pat_bindings(cx.tcx.def_map, p) |_, id, _, _| {
+                used = used || cx.tcx.used_mut_nodes.contains(&id);
+                bindings += 1;
+            }
+            if !used {
+                let msg = if bindings == 1 {
+                    "variable does not need to be mutable"
+                } else {
+                    "variables do not need to be mutable"
+                };
+                cx.span_lint(unused_mut, p.span, msg);
+            }
         }
+        _ => ()
     }
 }
 
@@ -1075,6 +1072,8 @@ impl Visitor<()> for Context {
 
     fn visit_pat(&mut self, p: @ast::Pat, _: ()) {
         check_pat_non_uppercase_statics(self, p);
+        check_unused_mut_pat(self, p);
+
         visit::walk_pat(self, p, ());
     }
 
@@ -1095,30 +1094,9 @@ impl Visitor<()> for Context {
         visit::walk_stmt(self, s, ());
     }
 
-    fn visit_ty_method(&mut self, tm: &ast::TypeMethod, _: ()) {
-        check_unused_mut_fn_decl(self, &tm.decl);
-        visit::walk_ty_method(self, tm, ());
-    }
-
-    fn visit_trait_method(&mut self, tm: &ast::trait_method, _: ()) {
-        match *tm {
-            ast::required(ref m) => check_unused_mut_fn_decl(self, &m.decl),
-            ast::provided(ref m) => check_unused_mut_fn_decl(self, &m.decl)
-        }
-        visit::walk_trait_method(self, tm, ());
-    }
-
-    fn visit_local(&mut self, l: @ast::Local, _: ()) {
-        if l.is_mutbl {
-            check_unused_mut_pat(self, l.pat);
-        }
-        visit::walk_local(self, l, ());
-    }
-
     fn visit_fn(&mut self, fk: &visit::fn_kind, decl: &ast::fn_decl,
                 body: &ast::Block, span: Span, id: ast::NodeId, _: ()) {
         let recurse = |this: &mut Context| {
-            check_unused_mut_fn_decl(this, decl);
             visit::walk_fn(this, fk, decl, body, span, id, ());
         };
 

src/librustc/middle/liveness.rs

@@ -429,18 +429,22 @@ fn visit_fn(v: &mut LivenessVisitor,
 
 fn visit_local(v: &mut LivenessVisitor, local: @Local, this: @mut IrMaps) {
     let def_map = this.tcx.def_map;
-    do pat_util::pat_bindings(def_map, local.pat) |_bm, p_id, sp, path| {
+    do pat_util::pat_bindings(def_map, local.pat) |bm, p_id, sp, path| {
         debug!("adding local variable {}", p_id);
         let name = ast_util::path_to_ident(path);
         this.add_live_node_for_node(p_id, VarDefNode(sp));
         let kind = match local.init {
           Some(_) => FromLetWithInitializer,
           None => FromLetNoInitializer
         };
+        let mutbl = match bm {
+            BindByValue(MutMutable) => true,
+            _ => false
+        };
         this.add_variable(Local(LocalInfo {
           id: p_id,
           ident: name,
-          is_mutbl: local.is_mutbl,
+          is_mutbl: mutbl,
           kind: kind
         }));
     }
@@ -454,11 +458,15 @@ fn visit_arm(v: &mut LivenessVisitor, arm: &Arm, this: @mut IrMaps) {
             debug!("adding local variable {} from match with bm {:?}",
                    p_id, bm);
             let name = ast_util::path_to_ident(path);
+            let mutbl = match bm {
+                BindByValue(MutMutable) => true,
+                _ => false
+            };
             this.add_live_node_for_node(p_id, VarDefNode(sp));
             this.add_variable(Local(LocalInfo {
                 id: p_id,
                 ident: name,
-                is_mutbl: false,
+                is_mutbl: mutbl,
                 kind: FromMatch(bm)
             }));
         }

src/librustc/middle/mem_categorization.rs

@@ -473,12 +473,15 @@ impl mem_categorization_ctxt {
               }
           }
 
-          ast::DefArg(vid, mutbl) => {
+          ast::DefArg(vid, binding_mode) => {
             // Idea: make this could be rewritten to model by-ref
             // stuff as `&const` and `&mut`?
 
             // m: mutability of the argument
-            let m = if mutbl {McDeclared} else {McImmutable};
+            let m = match binding_mode {
+                ast::BindByValue(ast::MutMutable) => McDeclared,
+                _ => McImmutable
+            };
             @cmt_ {
                 id: id,
                 span: span,
@@ -548,25 +551,20 @@ impl mem_categorization_ctxt {
               }
           }
 
-          ast::DefLocal(vid, mutbl) => {
-            let m = if mutbl {McDeclared} else {McImmutable};
-            @cmt_ {
-                id:id,
-                span:span,
-                cat:cat_local(vid),
-                mutbl:m,
-                ty:expr_ty
-            }
-          }
-
-          ast::DefBinding(vid, _) => {
+          ast::DefLocal(vid, binding_mode) |
+          ast::DefBinding(vid, binding_mode) => {
             // by-value/by-ref bindings are local variables
+            let m = match binding_mode {
+                ast::BindByValue(ast::MutMutable) => McDeclared,
+                _ => McImmutable
+            };
+
             @cmt_ {
-                id:id,
-                span:span,
-                cat:cat_local(vid),
-                mutbl:McImmutable,
-                ty:expr_ty
+                id: id,
+                span: span,
+                cat: cat_local(vid),
+                mutbl: m,
+                ty: expr_ty
             }
           }
         }

src/librustc/middle/moves.rs

@@ -618,7 +618,7 @@ impl VisitContext {
         do pat_bindings(self.tcx.def_map, pat) |bm, id, _span, path| {
             let binding_moves = match bm {
                 BindByRef(_) => false,
-                BindInfer => {
+                BindByValue(_) => {
                     let pat_ty = ty::node_id_to_type(self.tcx, id);
                     debug!("pattern {:?} {} type is {}",
                            id,

src/librustc/middle/resolve.rs

@@ -3817,11 +3817,8 @@ impl Resolver {
                 Some(declaration) => {
                     for argument in declaration.inputs.iter() {
                         let binding_mode = ArgumentIrrefutableMode;
-                        let mutability =
-                            if argument.is_mutbl {Mutable} else {Immutable};
                         this.resolve_pattern(argument.pat,
                                              binding_mode,
-                                             mutability,
                                              None);
 
                         this.resolve_type(&argument.ty);
@@ -4036,8 +4033,6 @@ impl Resolver {
     }
 
     fn resolve_local(&mut self, local: @Local) {
-        let mutability = if local.is_mutbl {Mutable} else {Immutable};
-
         // Resolve the type.
         self.resolve_type(&local.ty);
 
@@ -4052,7 +4047,7 @@ impl Resolver {
         }
 
         // Resolve the pattern.
-        self.resolve_pattern(local.pat, LocalIrrefutableMode, mutability, None);
+        self.resolve_pattern(local.pat, LocalIrrefutableMode, None);
     }
 
     // build a map from pattern identifiers to binding-info's.
@@ -4116,8 +4111,7 @@ impl Resolver {
 
         let bindings_list = @mut HashMap::new();
         for pattern in arm.pats.iter() {
-            self.resolve_pattern(*pattern, RefutableMode, Immutable,
-                                 Some(bindings_list));
+            self.resolve_pattern(*pattern, RefutableMode, Some(bindings_list));
         }
 
         // This has to happen *after* we determine which
@@ -4261,7 +4255,6 @@ impl Resolver {
     fn resolve_pattern(&mut self,
                        pattern: @Pat,
                        mode: PatternBindingMode,
-                       mutability: Mutability,
                        // Maps idents to the node ID for the (outermost)
                        // pattern that binds them
                        bindings_list: Option<@mut HashMap<Name,NodeId>>) {
@@ -4324,8 +4317,6 @@ impl Resolver {
                             debug!("(resolving pattern) binding `{}`",
                                    interner_get(renamed));
 
-                            let is_mutable = mutability == Mutable;
-
                             let def = match mode {
                                 RefutableMode => {
                                     // For pattern arms, we must use
@@ -4335,11 +4326,11 @@ impl Resolver {
                                 }
                                 LocalIrrefutableMode => {
                                     // But for locals, we use `def_local`.
-                                    DefLocal(pattern.id, is_mutable)
+                                    DefLocal(pattern.id, binding_mode)
                                 }
                                 ArgumentIrrefutableMode => {
                                     // And for function arguments, `def_arg`.
-                                    DefArg(pattern.id, is_mutable)
+                                    DefArg(pattern.id, binding_mode)
                                 }
                             };
 
@@ -5361,7 +5352,7 @@ impl Resolver {
                                         pat_binding_mode: BindingMode,
                                         descr: &str) {
         match pat_binding_mode {
-            BindInfer => {}
+            BindByValue(_) => {}
             BindByRef(*) => {
                 self.resolve_error(
                     pat.span,

src/librustc/middle/trans/_match.rs

@@ -1842,7 +1842,7 @@ fn create_bindings_map(bcx: @mut Block, pat: @ast::Pat) -> BindingsMap {
         let llmatch;
         let trmode;
         match bm {
-            ast::BindInfer => {
+            ast::BindByValue(_) => {
                 // in this case, the final type of the variable will be T,
                 // but during matching we need to store a *T as explained
                 // above
@@ -2130,7 +2130,7 @@ fn bind_irrefutable_pat(bcx: @mut Block,
                     bcx, pat.id, path, binding_mode,
                     |bcx, variable_ty, llvariable_val| {
                         match pat_binding_mode {
-                            ast::BindInfer => {
+                            ast::BindByValue(_) => {
                                 // By value binding: move the value that `val`
                                 // points at into the binding's stack slot.
                                 let datum = Datum {val: val,
@@ -2241,7 +2241,7 @@ fn bind_irrefutable_pat(bcx: @mut Block,
 
 fn simple_identifier<'a>(pat: &'a ast::Pat) -> Option<&'a ast::Path> {
     match pat.node {
-        ast::PatIdent(ast::BindInfer, ref path, None) => {
+        ast::PatIdent(ast::BindByValue(_), ref path, None) => {
             Some(path)
         }
         _ => {

src/librustc/middle/trans/base.rs

@@ -2065,7 +2065,6 @@ pub fn trans_enum_variant_or_tuple_like_struct<A:IdAndTy>(
     // Translate variant arguments to function arguments.
     let fn_args = do args.map |varg| {
         ast::arg {
-            is_mutbl: false,
             ty: (*varg.ty()).clone(),
             pat: ast_util::ident_to_pat(
                 ccx.tcx.sess.next_node_id(),

src/librustc/middle/typeck/check/_match.rs

@@ -476,7 +476,7 @@ pub fn check_pat(pcx: &pat_ctxt, pat: @ast::Pat, expected: ty::t) {
             demand::eqtype(fcx, pat.span, region_ty, typ);
           }
           // otherwise the type of x is the expected type T
-          ast::BindInfer => {
+          ast::BindByValue(_) => {
             demand::eqtype(fcx, pat.span, expected, typ);
           }
         }

src/libsyntax/ast.rs

@@ -232,8 +232,8 @@ pub enum Def {
     DefMod(DefId),
     DefForeignMod(DefId),
     DefStatic(DefId, bool /* is_mutbl */),
-    DefArg(NodeId, bool /* is_mutbl */),
-    DefLocal(NodeId, bool /* is_mutbl */),
+    DefArg(NodeId, BindingMode),
+    DefLocal(NodeId, BindingMode),
     DefVariant(DefId /* enum */, DefId /* variant */, bool /* is_structure */),
     DefTy(DefId),
     DefTrait(DefId),
@@ -324,7 +324,7 @@ pub struct FieldPat {
 #[deriving(Clone, Eq, Encodable, Decodable, IterBytes)]
 pub enum BindingMode {
     BindByRef(Mutability),
-    BindInfer
+    BindByValue(Mutability),
 }
 
 #[deriving(Clone, Eq, Encodable, Decodable, IterBytes)]
@@ -445,7 +445,6 @@ pub enum Stmt_ {
 // a refinement on pat.
 #[deriving(Eq, Encodable, Decodable,IterBytes)]
 pub struct Local {
-    is_mutbl: bool,
     ty: Ty,
     pat: @Pat,
     init: Option<@Expr>,
@@ -880,7 +879,6 @@ pub struct inline_asm {
 
 #[deriving(Clone, Eq, Encodable, Decodable, IterBytes)]
 pub struct arg {
-    is_mutbl: bool,
     ty: Ty,
     pat: @Pat,
     id: NodeId,

src/libsyntax/ast_util.rs

@@ -234,7 +234,7 @@ pub fn ident_to_path(s: Span, identifier: Ident) -> Path {
 
 pub fn ident_to_pat(id: NodeId, s: Span, i: Ident) -> @Pat {
     @ast::Pat { id: id,
-                node: PatIdent(BindInfer, ident_to_path(s, i), None),
+                node: PatIdent(BindByValue(MutImmutable), ident_to_path(s, i), None),
                 span: s }
 }