Tweak wording for borrows within macro invocations

Author: estebank

src/librustc_borrowck/borrowck/mod.rs

@@ -46,7 +46,7 @@ use std::fmt;
 use std::rc::Rc;
 use std::hash::{Hash, Hasher};
 use syntax::ast;
-use syntax_pos::{MultiSpan, Span};
+use syntax_pos::{MultiSpan, Span, SyntaxContext};
 use errors::{DiagnosticBuilder, DiagnosticId};
 
 use rustc::hir;
@@ -723,18 +723,17 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
 
         // Annotate the use and the move in the span. Watch out for
         // the case where the use and the move are the same. This
-        // means the use is in a loop.
-        err = if use_span == move_span {
-            err.span_label(
-                use_span,
-                format!("value moved{} here in previous iteration of loop",
-                         move_note));
-            err
+        // means the use is in a loop or within the same macro invocation.
+        if use_span == move_span && use_span.ctxt() != SyntaxContext::empty() {
+            err.span_label(use_span, format!("value moved{} here in previous iteration of loop",
+                                             move_note));
+        } else if use_span == move_span {
+            err.span_label(use_span, format!("value moved{} inside this macro invocation",
+                                             move_note));
         } else {
             err.span_label(use_span, format!("value {} here after move", verb_participle));
             err.span_label(move_span, format!("value moved{} here", move_note));
-            err
-        };
+        }
 
         if need_note {
             err.note(&format!(

src/librustc_mir/borrow_check/error_reporting.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use syntax_pos::Span;
+use syntax_pos::{Span, SyntaxContext};
 use rustc::middle::region::ScopeTree;
 use rustc::mir::{BorrowKind, Field, Local, LocalKind, Location, Operand};
 use rustc::mir::{Place, ProjectionElem, Rvalue, Statement, StatementKind};
@@ -66,11 +66,14 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
             for moi in mois {
                 let move_msg = ""; //FIXME: add " (into closure)"
                 let move_span = self.mir.source_info(self.move_data.moves[*moi].source).span;
-                if span == move_span {
-                    err.span_label(
-                        span,
-                        format!("value moved{} here in previous iteration of loop", move_msg),
-                    );
+                if span == move_span && span.ctxt() != SyntaxContext::empty() {
+                    err.span_label(span, format!("value moved{} inside this macro invocation",
+                                                 move_msg));
+                    is_loop_move = true;
+                } else if span == move_span {
+                    err.span_label(span,
+                                   format!("value moved{} here in previous iteration of loop",
+                                           move_msg));
                     is_loop_move = true;
                 } else {
                     err.span_label(move_span, format!("value moved{} here", move_msg));

src/test/ui/borrowck/moves-inside-of-macro.rs

@@ -0,0 +1,25 @@
+// Copyright 2018 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.
+
+// compile-flags: -Z borrowck=compare
+
+macro_rules! test {
+    ($v:expr) => {{
+        drop(&$v);
+        $v
+    }}
+}
+
+fn main() {
+    let b = Box::new(true);
+    test!({b});
+    //~^ ERROR use of moved value: `b` (Ast)
+    //~^^ ERROR use of moved value: `b` (Mir)
+}

src/test/ui/borrowck/moves-inside-of-macro.stderr

@@ -0,0 +1,10 @@
+error[E0382]: use of moved value: `b`
+  --> $DIR/moves-inside-of-macro.rs:20:12
+   |
+20 |     test!({b});
+   |            ^ value moved inside this macro invocation
+   |
+   = note: move occurs because `b` has type `std::boxed::Box<bool>`, which does not implement the `Copy` trait
+
+error: aborting due to previous error
+