Link the lifetimes of regions resulting from borrows of the

contents of other borrowed pointers to the lifetimes of the
borrowed value.  Fixes #3148.

Author: nikomatsakis

src/librustc/middle/mem_categorization.rs

@@ -111,6 +111,8 @@ enum special_kind {
 // a complete categorization of a value indicating where it originated
 // and how it is located, as well as the mutability of the memory in
 // which the value is stored.
+//
+// note: cmt stands for "categorized mutable type".
 type cmt_ = {id: ast::node_id,        // id of expr/pat producing this value
              span: span,              // span of same expr/pat
              cat: categorization,     // categorization of expr

src/librustc/middle/resolve.rs

@@ -25,6 +25,7 @@ use core::str;
 use core::vec;
 use syntax::ast::{RegionTyParamBound, TraitTyParamBound, _mod, add, arm};
 use syntax::ast::{binding_mode, bitand, bitor, bitxor, blk, capture_clause};
+use syntax::ast::{bind_by_value, bind_infer, bind_by_ref, bind_by_move};
 use syntax::ast::{crate, crate_num, decl_item, def, def_arg, def_binding};
 use syntax::ast::{def_const, def_foreign_mod, def_fn, def_id, def_label};
 use syntax::ast::{def_local, def_mod, def_prim_ty, def_region, def_self};
@@ -4521,6 +4522,10 @@ impl Resolver {
                                     struct or enum variant",
                                     self.session.str_of(ident));
 
+                            self.enforce_default_binding_mode(
+                                pattern,
+                                binding_mode,
+                                "an enum variant");
                             self.record_def(pattern.id, def);
                         }
                         FoundStructOrEnumVariant(_) => {
@@ -4537,6 +4542,10 @@ impl Resolver {
                                     constant",
                                     self.session.str_of(ident));
 
+                            self.enforce_default_binding_mode(
+                                pattern,
+                                binding_mode,
+                                "a constant");
                             self.record_def(pattern.id, def);
                         }
                         FoundConst(_) => {
@@ -5371,6 +5380,32 @@ impl Resolver {
         self.def_map.insert(node_id, def);
     }
 
+    fn enforce_default_binding_mode(pat: @pat,
+                                    pat_binding_mode: binding_mode,
+                                    descr: &str) {
+        match pat_binding_mode {
+            bind_infer => {}
+            bind_by_value => {
+                self.session.span_err(
+                    pat.span,
+                    fmt!("cannot use `copy` binding mode with %s",
+                         descr));
+            }
+            bind_by_move => {
+                self.session.span_err(
+                    pat.span,
+                    fmt!("cannot use `move` binding mode with %s",
+                         descr));
+            }
+            bind_by_ref(*) => {
+                self.session.span_err(
+                    pat.span,
+                    fmt!("cannot use `ref` binding mode with %s",
+                         descr));
+            }
+        }
+    }
+
     //
     // main function checking
     //

src/librustc/middle/ty.rs

@@ -119,6 +119,7 @@ export ty_opaque_box, mk_opaque_box;
 export ty_float, mk_float, mk_mach_float, type_is_fp;
 export ty_fn, FnTy, FnTyBase, FnMeta, FnSig, mk_fn;
 export ty_fn_proto, ty_fn_purity, ty_fn_ret, tys_in_fn_sig;
+export ty_vstore;
 export replace_fn_return_type;
 export ty_int, mk_int, mk_mach_int, mk_char;
 export mk_i8, mk_u8, mk_i16, mk_u16, mk_i32, mk_u32, mk_i64, mk_u64;
@@ -3005,6 +3006,14 @@ fn is_fn_ty(fty: t) -> bool {
     }
 }
 
+pure fn ty_vstore(ty: t) -> vstore {
+    match get(ty).sty {
+        ty_evec(_, vstore) => vstore,
+        ty_estr(vstore) => vstore,
+        ref s => fail fmt!("ty_vstore() called on invalid sty: %?", s)
+    }
+}
+
 fn ty_region(ty: t) -> Region {
     match get(ty).sty {
       ty_rptr(r, _) => r,

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

@@ -105,7 +105,7 @@ use middle::typeck::{isr_alist, lookup_def_ccx, method_map_entry};
 use middle::typeck::{method_origin, method_self, method_trait, no_params};
 use middle::typeck::{require_same_types};
 use util::common::{block_query, indenter, loop_query};
-use util::ppaux::{bound_region_to_str, expr_repr};
+use util::ppaux::{bound_region_to_str, expr_repr, pat_repr};
 use util::ppaux;
 
 use core::either;
@@ -127,7 +127,6 @@ use syntax::ast_util;
 use syntax::codemap::span;
 use syntax::codemap;
 use syntax::parse::token::special_idents;
-use syntax::print::pprust::{expr_to_str, pat_to_str};
 use syntax::print::pprust;
 use syntax::visit;
 use syntax;
@@ -469,7 +468,7 @@ fn check_fn(ccx: @crate_ctxt,
             };
             assign(local.span, local.node.id, o_ty);
             debug!("Local variable %s is assigned to %s",
-                   pat_to_str(local.node.pat, tcx.sess.intr()),
+                   fcx.pat_to_str(local.node.pat),
                    fcx.inh.locals.get(local.node.id).to_str());
             visit::visit_local(local, e, v);
         };
@@ -756,6 +755,10 @@ impl @fn_ctxt {
         expr_repr(self.tcx(), expr)
     }
 
+    fn pat_to_str(pat: @ast::pat) -> ~str {
+        pat_repr(self.tcx(), pat)
+    }
+
     fn expr_ty(ex: @ast::expr) -> ty::t {
         match self.inh.node_types.find(ex.id) {
             Some(t) => t,
@@ -1600,7 +1603,7 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
         let fty = ty::mk_fn(tcx, copy fn_ty);
 
         debug!("check_expr_fn_with_unifier %s fty=%s",
-               expr_to_str(expr, tcx.sess.intr()),
+               fcx.expr_to_str(expr),
                fcx.infcx().ty_to_str(fty));
 
         fcx.write_ty(expr.id, fty);
@@ -2713,7 +2716,7 @@ fn check_enum_variants(ccx: @crate_ctxt,
             do v.node.disr_expr.iter |e_ref| {
                 let e = *e_ref;
                 debug!("disr expr, checking %s",
-                       expr_to_str(e, ccx.tcx.sess.intr()));
+                       pprust::expr_to_str(e, ccx.tcx.sess.intr()));
                 let declty = ty::mk_int(ccx.tcx);
                 let fcx = blank_fn_ctxt(ccx, rty, e.id);
                 check_const_with_ty(fcx, e.span, e, declty);