Allow mutable slices in statics.

Fixes #11411

Author: xales

Diff for: src/librustc/middle/borrowck/check_loans.rs

@@ -520,6 +520,9 @@ impl<'a> CheckLoanCtxt<'a> {
                 None => {
                     return true;
                 }
+                Some(mc::AliasableStaticMut) => {
+                    return true;
+                }
                 Some(cause) => {
                     this.bccx.report_aliasability_violation(
                         expr.span,

Diff for: src/librustc/middle/check_const.rs

@@ -29,14 +29,15 @@ pub struct CheckCrateVisitor {
 
 impl Visitor<bool> for CheckCrateVisitor {
     fn visit_item(&mut self, i: &Item, env: bool) {
-        check_item(self, self.sess, self.def_map, i, env);
+        check_item(self, self.sess, self.def_map, self.method_map,
+                   self.tcx, i, env)
     }
     fn visit_pat(&mut self, p: &Pat, env: bool) {
         check_pat(self, p, env);
     }
     fn visit_expr(&mut self, ex: &Expr, env: bool) {
         check_expr(self, self.sess, self.def_map, self.method_map,
-                   self.tcx, ex, env);
+                   self.tcx, ex, env, false);
     }
 }
 
@@ -58,11 +59,13 @@ pub fn check_crate(sess: Session,
 pub fn check_item(v: &mut CheckCrateVisitor,
                   sess: Session,
                   def_map: resolve::DefMap,
+                  method_map: typeck::method_map,
+                  tcx: ty::ctxt,
                   it: &Item,
                   _is_const: bool) {
     match it.node {
-        ItemStatic(_, _, ex) => {
-            v.visit_expr(ex, true);
+        ItemStatic(_, mut_, ex) => {
+            check_expr(v, sess, def_map, method_map, tcx, ex, true, mut_ == MutMutable);
             check_item_recursion(sess, &v.tcx.map, def_map, it);
         }
         ItemEnum(ref enum_definition, _) => {
@@ -105,7 +108,8 @@ pub fn check_expr(v: &mut CheckCrateVisitor,
                   method_map: typeck::MethodMap,
                   tcx: ty::ctxt,
                   e: &Expr,
-                  is_const: bool) {
+                  is_const: bool,
+                  is_static_mut: bool) {
     if is_const {
         match e.node {
           ExprUnary(UnDeref, _) => { }
@@ -187,6 +191,11 @@ pub fn check_expr(v: &mut CheckCrateVisitor,
                     e.span,
                     "references in constants may only refer to \
                      immutable values");
+          }
+          ExprVstore(_, ExprVstoreMutSlice) => {
+              if !is_static_mut {
+                  sess.span_err(e.span, "mutable slice is not allowed in immutable constants")
+              }
           },
           ExprVstore(_, ExprVstoreUniq) => {
               sess.span_err(e.span, "cannot allocate vectors in constant expressions")

Diff for: src/librustc/middle/trans/consts.rs

@@ -10,7 +10,8 @@
 
 
 use back::abi;
-use lib::llvm::{llvm, ConstFCmp, ConstICmp, SetLinkage, PrivateLinkage, ValueRef, Bool, True};
+use lib::llvm::{llvm, ConstFCmp, ConstICmp, SetLinkage, PrivateLinkage, ValueRef, Bool, True,
+    False};
 use lib::llvm::{IntEQ, IntNE, IntUGT, IntUGE, IntULT, IntULE, IntSGT, IntSGE, IntSLT, IntSLE,
     RealOEQ, RealOGT, RealOGE, RealOLT, RealOLE, RealONE};
 
@@ -572,7 +573,8 @@ fn const_expr_unadjusted(cx: @CrateContext, e: &ast::Expr,
                                                is_local);
             (v, inlineable)
           }
-          ast::ExprVstore(sub, ast::ExprVstoreSlice) => {
+          ast::ExprVstore(sub, store @ ast::ExprVstoreSlice) |
+              ast::ExprVstore(sub, store @ ast::ExprVstoreMutSlice) => {
             match sub.node {
               ast::ExprLit(ref lit) => {
                 match lit.node {
@@ -590,7 +592,8 @@ fn const_expr_unadjusted(cx: @CrateContext, e: &ast::Expr,
                     llvm::LLVMAddGlobal(cx.llmod, llty.to_ref(), name)
                 });
                 llvm::LLVMSetInitializer(gv, cv);
-                llvm::LLVMSetGlobalConstant(gv, True);
+                llvm::LLVMSetGlobalConstant(gv,
+                      if store == ast::ExprVstoreMutSlice { False } else { True });
                 SetLinkage(gv, PrivateLinkage);
                 let p = const_ptrcast(cx, gv, llunitty);
                 (C_struct([p, C_uint(cx, es.len())], false), false)

Diff for: src/test/compile-fail/issue-11411.rs

@@ -0,0 +1,13 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+static TEST: &'static mut [int] = &mut []; //~ ERROR mutable slice is not allowed
+
+fn main() { }

Diff for: src/test/run-pass/issue-11411.rs

@@ -0,0 +1,18 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+
+static mut TEST: &'static mut [int] = &mut [1];
+
+pub fn main() {
+    unsafe {
+        TEST[0] += 1;
+    }
+}