libsyntax: Forbid mutable vectors. rs=demuting

2 files changed, 15 insertions, 0 deletions

diff --git a/src/libsyntax/parse/obsolete.rs b/src/libsyntax/parse/obsolete.rs
index 0c5c0f3d513..33d959a7753 100644
--- a/src/libsyntax/parse/obsolete.rs
+++ b/src/libsyntax/parse/obsolete.rs
@@ -49,6 +49,7 @@ pub enum ObsoleteSyntax {
     ObsoleteImplSyntax,
     ObsoleteTraitBoundSeparator,
     ObsoleteMutOwnedPointer,
+    ObsoleteMutVector,
 }
 
 pub impl to_bytes::IterBytes for ObsoleteSyntax {
@@ -133,6 +134,12 @@ pub impl Parser {
                  in a mutable location, like a mutable local variable or an \
                  `@mut` box"
             ),
+            ObsoleteMutVector => (
+                "const or mutable vector",
+                "mutability inherits through `~` pointers; place the vector \
+                 in a mutable location, like a mutable local variable or an \
+                 `@mut` box"
+            ),
         };
 
         self.report(sp, kind, kind_str, desc);
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index c9102cbb86b..b4bd28cbfe2 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -76,6 +76,7 @@ use parse::obsolete::{ObsoleteStructCtor, ObsoleteWith};
 use parse::obsolete::{ObsoleteSyntax, ObsoleteLowerCaseKindBounds};
 use parse::obsolete::{ObsoleteUnsafeBlock, ObsoleteImplSyntax};
 use parse::obsolete::{ObsoleteTraitBoundSeparator, ObsoleteMutOwnedPointer};
+use parse::obsolete::{ObsoleteMutVector};
 use parse::prec::{as_prec, token_to_binop};
 use parse::token::{can_begin_expr, is_ident, is_ident_or_path};
 use parse::token::{is_plain_ident, INTERPOLATED, special_idents};
@@ -624,6 +625,9 @@ pub impl Parser {
         } else if *self.token == token::LBRACKET {
             self.expect(token::LBRACKET);
             let mt = self.parse_mt();
+            if mt.mutbl == m_mutbl {    // `m_const` too after snapshot
+                self.obsolete(*self.last_span, ObsoleteMutVector);
+            }
 
             // Parse the `* 3` in `[ int * 3 ]`
             let t = match self.maybe_parse_fixed_vstore_with_star() {
@@ -1134,6 +1138,10 @@ pub impl Parser {
         } else if *self.token == token::LBRACKET {
             self.bump();
             let mutbl = self.parse_mutability();
+            if mutbl == m_mutbl {   // `m_const` too after snapshot
+                self.obsolete(*self.last_span, ObsoleteMutVector);
+            }
+
             if *self.token == token::RBRACKET {
                 // Empty vector.
                 self.bump();