From e6e58e43f8f9507474fdf35544b6b0c0fc6cef39 Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Tue, 11 Nov 2014 10:45:59 -0800
Subject: [PATCH] libsyntax: Forbid type parameters in field expressions.
This breaks code like:
struct Foo {
x: int,
}
let f: Foo = ...;
... f.x::<int> ...
Change this code to not contain an unused type parameter. For example:
struct Foo {
x: int,
}
let f: Foo = ...;
... f.x ...
Closes #18680.
[breaking-change]
---
src/libsyntax/parse/parser.rs | 9 ++++++-
.../type-parameters-in-field-exprs.rs | 24 +++++++++++++++++++
2 files changed, 32 insertions(+), 1 deletion(-)
create mode 100644 src/test/compile-fail/type-parameters-in-field-exprs.rs
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 6873c015fd5..90ada8a687c 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -2415,9 +2415,16 @@ impl<'a> Parser<'a> {
e = self.mk_expr(lo, hi, nd);
}
_ => {
+ if !tys.is_empty() {
+ let last_span = self.last_span;
+ self.span_err(last_span,
+ "field expressions may not \
+ have type parameters");
+ }
+
let id = spanned(dot, hi, i);
let field = self.mk_field(e, id, tys);
- e = self.mk_expr(lo, hi, field)
+ e = self.mk_expr(lo, hi, field);
}
}
}
diff --git a/src/test/compile-fail/type-parameters-in-field-exprs.rs b/src/test/compile-fail/type-parameters-in-field-exprs.rs
new file mode 100644
index 00000000000..023f7d1c29f
--- /dev/null
+++ b/src/test/compile-fail/type-parameters-in-field-exprs.rs
@@ -0,0 +1,24 @@
+// 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.
+
+struct Foo {
+ x: int,
+ y: int,
+}
+
+fn main() {
+ let f = Foo {
+ x: 1,
+ y: 2,
+ };
+ f.x::<int>;
+ //~^ ERROR field expressions may not have type parameters
+}
+