Add type argument field to expr_path

This way, you can explicitly provide type parameters when calling a
generic method.

Issue #1227

Author: marijnh

src/comp/middle/mut.rs

@@ -47,7 +47,7 @@ fn expr_root(tcx: ty::ctxt, ex: @expr, autoderef: bool) ->
     let ds: [deref] = [], ex = ex;
     while true {
         alt copy ex.node {
-          expr_field(base, ident) {
+          expr_field(base, ident, _) {
             let auto_unbox = maybe_auto_unbox(tcx, ty::expr_ty(tcx, base));
             let is_mut = false;
             alt ty::struct(tcx, auto_unbox.t) {

src/comp/middle/resolve.rs

@@ -1771,7 +1771,7 @@ fn visit_mod_with_impl_scope(e: @env, m: ast::_mod, s: span, sc: iscopes,
 
 fn resolve_impl_in_expr(e: @env, x: @ast::expr, sc: iscopes, v: vt<iscopes>) {
     alt x.node {
-      ast::expr_field(_, _) { e.impl_map.insert(x.id, sc); }
+      ast::expr_field(_, _, _) { e.impl_map.insert(x.id, sc); }
       _ {}
     }
     visit::visit_expr(x, sc, v);

src/comp/middle/trans.rs

@@ -2858,7 +2858,7 @@ fn trans_method_callee(bcx: @block_ctxt, e: @ast::expr, base: @ast::expr,
 fn trans_callee(bcx: @block_ctxt, e: @ast::expr) -> lval_maybe_callee {
     alt e.node {
       ast::expr_path(p) { ret trans_path(bcx, p, e.id); }
-      ast::expr_field(base, ident) {
+      ast::expr_field(base, ident, _) {
         // Lval means this is a record field, so not a method
         if !expr_is_lval(bcx, e) {
             alt bcx_ccx(bcx).method_map.find(e.id) {
@@ -2889,7 +2889,7 @@ fn trans_lval(cx: @block_ctxt, e: @ast::expr) -> lval_result {
         let v = trans_path(cx, p, e.id);
         ret lval_maybe_callee_to_lval(v, ty::expr_ty(bcx_tcx(cx), e));
       }
-      ast::expr_field(base, ident) {
+      ast::expr_field(base, ident, _) {
         ret trans_rec_field(cx, base, ident);
       }
       ast::expr_index(base, idx) {
@@ -3580,7 +3580,7 @@ fn trans_expr(bcx: @block_ctxt, e: @ast::expr, dest: dest) -> @block_ctxt {
       ast::expr_call(f, args, _) {
         ret trans_call(bcx, f, args, e.id, dest);
       }
-      ast::expr_field(_, _) {
+      ast::expr_field(_, _, _) {
         fail "Taking the value of a method does not work yet (issue #435)";
       }
 

src/comp/middle/tstate/pre_post_conditions.rs

@@ -476,7 +476,7 @@ fn find_pre_post_expr(fcx: fn_ctxt, e: @expr) {
         set_pre_and_post(fcx.ccx, e.id, alts_overall_pp.precondition,
                          alts_overall_pp.postcondition);
       }
-      expr_field(operator, _) {
+      expr_field(operator, _, _) {
         find_pre_post_expr(fcx, operator);
         copy_pre_post(fcx.ccx, e.id, operator);
       }

src/comp/middle/tstate/states.rs

@@ -551,7 +551,7 @@ fn find_pre_post_state_expr(fcx: fn_ctxt, pres: prestate, e: @expr) -> bool {
         }
         ret changed | set_poststate_ann(fcx.ccx, e.id, a_post);
       }
-      expr_field(val, _) {
+      expr_field(val, _, _) {
         ret find_pre_post_state_sub(fcx, pres, val, e.id, none);
       }
       expr_unary(_, operand) {

src/comp/middle/ty.rs

@@ -1678,7 +1678,7 @@ fn expr_is_lval(method_map: typeck::method_map, tcx: ty::ctxt,
     alt e.node {
       ast::expr_path(_) | ast::expr_index(_, _) |
       ast::expr_unary(ast::deref., _) { true }
-      ast::expr_field(base, ident) {
+      ast::expr_field(base, ident, _) {
         method_map.contains_key(e.id) ? false : {
             let basety = type_autoderef(tcx, expr_ty(tcx, base));
             alt struct(tcx, basety) {

src/comp/middle/typeck.rs

@@ -2132,15 +2132,20 @@ fn check_expr_with_unifier(fcx: @fn_ctxt, expr: @ast::expr, unify: unifier,
           }
         }
       }
-      ast::expr_field(base, field) {
+      ast::expr_field(base, field, tys) {
         bot |= check_expr(fcx, base);
         let expr_t = expr_ty(tcx, base);
         let base_t = do_autoderef(fcx, expr.span, expr_t);
-        let handled = false;
+        let handled = false, n_tys = vec::len(tys);
         alt structure_of(fcx, expr.span, base_t) {
           ty::ty_rec(fields) {
             alt ty::field_idx(field, fields) {
               some(ix) {
+                if n_tys > 0u {
+                    tcx.sess.span_err(expr.span,
+                                      "can't provide type parameters \
+                                       to a field access");
+                }
                 write::ty_only_fixup(fcx, id, fields[ix].mt.ty);
                 handled = true;
               }
@@ -2150,6 +2155,11 @@ fn check_expr_with_unifier(fcx: @fn_ctxt, expr: @ast::expr, unify: unifier,
           ty::ty_obj(methods) {
             alt ty::method_idx(field, methods) {
               some(ix) {
+                if n_tys > 0u {
+                    tcx.sess.span_err(expr.span,
+                                      "can't provide type parameters \
+                                       to an obj method");
+                }
                 let meth = methods[ix];
                 let t = ty::mk_fn(tcx, meth.proto, meth.inputs,
                                   meth.output, meth.cf, meth.constrs);
@@ -2181,6 +2191,25 @@ fn check_expr_with_unifier(fcx: @fn_ctxt, expr: @ast::expr, unify: unifier,
                                                 fty, method.n_tps);
                     ids += b.ids;
                     fty = b.ty;
+                    if n_tys > 0u {
+                        if n_tys != method.n_tps {
+                            tcx.sess.span_fatal
+                                (expr.span, "incorrect number of type \
+                                           parameters given for this method");
+
+                        }
+                        let i = 0u;
+                        for ty in tys {
+                            let tvar = ty::mk_var(fcx.ccx.tcx, b.ids[i]);
+                            let t_subst = ast_ty_to_ty_crate(fcx.ccx, ty);
+                            demand::simple(fcx, expr.span, tvar, t_subst);
+                            i += 1u;
+                        }
+                    }
+                } else if n_tys > 0u {
+                    tcx.sess.span_fatal(expr.span,
+                                        "this method does not take type \
+                                         parameters");
                 }
                 let substs = vec::map(ids, {|id| ty::mk_var(tcx, id)});
                 write::ty_fixup(fcx, id, {substs: some(substs), ty: fty});

src/comp/syntax/ast.rs

@@ -238,7 +238,7 @@ tag expr_ {
     expr_assign(@expr, @expr);
     expr_swap(@expr, @expr);
     expr_assign_op(binop, @expr, @expr);
-    expr_field(@expr, ident);
+    expr_field(@expr, ident, [@ty]);
     expr_index(@expr, @expr);
     expr_path(@path);
     expr_fail(option::t<@expr>);

src/comp/syntax/fold.rs

@@ -401,8 +401,9 @@ fn noop_fold_expr(e: expr_, fld: ast_fold) -> expr_ {
           expr_assign_op(op, el, er) {
             expr_assign_op(op, fld.fold_expr(el), fld.fold_expr(er))
           }
-          expr_field(el, id) {
-            expr_field(fld.fold_expr(el), fld.fold_ident(id))
+          expr_field(el, id, tys) {
+            expr_field(fld.fold_expr(el), fld.fold_ident(id),
+                       vec::map(tys, fld.fold_ty))
           }
           expr_index(el, er) {
             expr_index(fld.fold_expr(el), fld.fold_expr(er))

src/comp/syntax/parse/parser.rs

@@ -1025,7 +1025,12 @@ fn parse_dot_or_call_expr_with(p: parser, e: @ast::expr) -> @ast::expr {
               token::IDENT(i, _) {
                 hi = p.get_hi_pos();
                 p.bump();
-                e = mk_expr(p, lo, hi, ast::expr_field(e, p.get_str(i)));
+                let tys = if eat(p, token::MOD_SEP) {
+                    expect(p, token::LT);
+                    parse_seq_to_gt(some(token::COMMA),
+                                    {|p| parse_ty(p, false)}, p)
+                } else { [] };
+                e = mk_expr(p, lo, hi, ast::expr_field(e, p.get_str(i), tys));
               }
               t { unexpected(p, t); }
             }