Add E0615

Author: GuillaumeGomez

src/librustc_typeck/check/mod.rs

@@ -2933,10 +2933,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         } else if field.node == keywords::Invalid.name() {
             self.tcx().types.err
         } else if self.method_exists(field.span, field.node, expr_t, expr.id, true) {
-            self.type_error_struct(field.span, |actual| {
-                format!("attempted to take value of method `{}` on type \
-                         `{}`", field.node, actual)
-            }, expr_t)
+            type_error_struct!(self.tcx().sess, field.span, expr_t, E0615,
+                              "attempted to take value of method `{}` on type `{}`",
+                              field.node, expr_t)
                 .help("maybe a `()` to call it is missing? \
                        If not, try an anonymous function")
                 .emit();

src/librustc_typeck/diagnostics.rs

@@ -4307,6 +4307,38 @@ let x = &y;
 ```
 "##,
 
+E0615: r##"
+Attempted to access a method like a field.
+
+Erroneous code example:
+
+```compile_fail,E0615
+struct Foo {
+    x: u32,
+}
+
+impl Foo {
+    fn method(&self) {}
+}
+
+let f = Foo { x: 0 };
+f.method; // error: attempted to take value of method `method` on type `Foo`
+```
+
+If you want to use a method, add `()` after it:
+
+```ignore
+f.method();
+```
+
+However, if you wanted to access a field of a struct check that the field name
+is spelled correctly. Example:
+
+```ignore
+println!("{}", f.x);
+```
+"##,
+
 E0617: r##"
 Attempted to pass an invalid type of variable into a variadic function.
 

src/test/compile-fail/E0615.rs

@@ -0,0 +1,22 @@
+// Copyright 2017 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: u32,
+}
+
+impl Foo {
+    fn method(&self) {}
+}
+
+fn main() {
+    let f = Foo { x: 0 };
+    f.method; //~ ERROR E0615
+}