Rollup merge of #28443 - GuillaumeGomez:error_codes, r=Manishearth

r? @Manishearth 

7 files changed, 133 insertions, 65 deletions

diff --git a/src/librustc_borrowck/borrowck/check_loans.rs b/src/librustc_borrowck/borrowck/check_loans.rs
index eed8f82b5d8..43e9cdd73c4 100644
--- a/src/librustc_borrowck/borrowck/check_loans.rs
+++ b/src/librustc_borrowck/borrowck/check_loans.rs
@@ -464,40 +464,36 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
 
             match (new_loan.kind, old_loan.kind) {
                 (ty::MutBorrow, ty::MutBorrow) => {
-                    self.bccx.span_err(
-                        new_loan.span,
-                        &format!("cannot borrow `{}`{} as mutable \
-                                more than once at a time",
-                                nl, new_loan_msg))
+                    span_err!(self.bccx, new_loan.span, E0499,
+                              "cannot borrow `{}`{} as mutable \
+                               more than once at a time",
+                              nl, new_loan_msg);
                 }
 
                 (ty::UniqueImmBorrow, _) => {
-                    self.bccx.span_err(
-                        new_loan.span,
-                        &format!("closure requires unique access to `{}` \
-                                but {} is already borrowed{}",
-                                nl, ol_pronoun, old_loan_msg));
+                    span_err!(self.bccx, new_loan.span, E0500,
+                              "closure requires unique access to `{}` \
+                               but {} is already borrowed{}",
+                              nl, ol_pronoun, old_loan_msg);
                 }
 
                 (_, ty::UniqueImmBorrow) => {
-                    self.bccx.span_err(
-                        new_loan.span,
-                        &format!("cannot borrow `{}`{} as {} because \
-                                previous closure requires unique access",
-                                nl, new_loan_msg, new_loan.kind.to_user_str()));
+                    span_err!(self.bccx, new_loan.span, E0501,
+                              "cannot borrow `{}`{} as {} because \
+                               previous closure requires unique access",
+                              nl, new_loan_msg, new_loan.kind.to_user_str());
                 }
 
                 (_, _) => {
-                    self.bccx.span_err(
-                        new_loan.span,
-                        &format!("cannot borrow `{}`{} as {} because \
-                                {} is also borrowed as {}{}",
-                                nl,
-                                new_loan_msg,
-                                new_loan.kind.to_user_str(),
-                                ol_pronoun,
-                                old_loan.kind.to_user_str(),
-                                old_loan_msg));
+                    span_err!(self.bccx, new_loan.span, E0502,
+                              "cannot borrow `{}`{} as {} because \
+                               {} is also borrowed as {}{}",
+                              nl,
+                              new_loan_msg,
+                              new_loan.kind.to_user_str(),
+                              ol_pronoun,
+                              old_loan.kind.to_user_str(),
+                              old_loan_msg);
                 }
             }
 
@@ -617,11 +613,9 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
         match self.analyze_restrictions_on_use(id, copy_path, ty::ImmBorrow) {
             UseOk => { }
             UseWhileBorrowed(loan_path, loan_span) => {
-                self.bccx.span_err(
-                    span,
-                    &format!("cannot use `{}` because it was mutably borrowed",
-                            &self.bccx.loan_path_to_string(copy_path))
-                    );
+                span_err!(self.bccx, span, E0503,
+                          "cannot use `{}` because it was mutably borrowed",
+                          &self.bccx.loan_path_to_string(copy_path));
                 self.bccx.span_note(
                     loan_span,
                     &format!("borrow of `{}` occurs here",
@@ -642,18 +636,19 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
         match self.analyze_restrictions_on_use(id, move_path, ty::MutBorrow) {
             UseOk => { }
             UseWhileBorrowed(loan_path, loan_span) => {
-                let err_message = match move_kind {
+                match move_kind {
                     move_data::Captured =>
-                        format!("cannot move `{}` into closure because it is borrowed",
-                                &self.bccx.loan_path_to_string(move_path)),
+                        span_err!(self.bccx, span, E0504,
+                                  "cannot move `{}` into closure because it is borrowed",
+                                  &self.bccx.loan_path_to_string(move_path)),
                     move_data::Declared |
                     move_data::MoveExpr |
                     move_data::MovePat =>
-                        format!("cannot move out of `{}` because it is borrowed",
-                                &self.bccx.loan_path_to_string(move_path))
+                        span_err!(self.bccx, span, E0505,
+                                  "cannot move out of `{}` because it is borrowed",
+                                  &self.bccx.loan_path_to_string(move_path))
                 };
 
-                self.bccx.span_err(span, &err_message[..]);
                 self.bccx.span_note(
                     loan_span,
                     &format!("borrow of `{}` occurs here",
@@ -820,10 +815,9 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
                                    span: Span,
                                    loan_path: &LoanPath<'tcx>,
                                    loan: &Loan) {
-        self.bccx.span_err(
-            span,
-            &format!("cannot assign to `{}` because it is borrowed",
-                    self.bccx.loan_path_to_string(loan_path)));
+        span_err!(self.bccx, span, E0506,
+                  "cannot assign to `{}` because it is borrowed",
+                  self.bccx.loan_path_to_string(loan_path));
         self.bccx.span_note(
             loan.span,
             &format!("borrow of `{}` occurs here",
diff --git a/src/librustc_borrowck/borrowck/gather_loans/move_error.rs b/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
index c39b1a9da07..bbcf5193342 100644
--- a/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
+++ b/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
@@ -119,18 +119,18 @@ fn report_cannot_move_out_of<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
         mc::cat_deref(_, _, mc::Implicit(..)) |
         mc::cat_deref(_, _, mc::UnsafePtr(..)) |
         mc::cat_static_item => {
-            bccx.span_err(move_from.span,
-                          &format!("cannot move out of {}",
-                                  move_from.descriptive_string(bccx.tcx)));
+            span_err!(bccx, move_from.span, E0507,
+                      "cannot move out of {}",
+                      move_from.descriptive_string(bccx.tcx));
         }
 
         mc::cat_interior(ref b, mc::InteriorElement(Kind::Index, _)) => {
             let expr = bccx.tcx.map.expect_expr(move_from.id);
             if let hir::ExprIndex(..) = expr.node {
-                bccx.span_err(move_from.span,
-                              &format!("cannot move out of type `{}`, \
-                                        a non-copy fixed-size array",
-                                       b.ty));
+                span_err!(bccx, move_from.span, E0508,
+                          "cannot move out of type `{}`, \
+                           a non-copy fixed-size array",
+                          b.ty);
             }
         }
 
@@ -139,11 +139,10 @@ fn report_cannot_move_out_of<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
             match b.ty.sty {
                 ty::TyStruct(def, _) |
                 ty::TyEnum(def, _) if def.has_dtor() => {
-                    bccx.span_err(
-                        move_from.span,
-                        &format!("cannot move out of type `{}`, \
-                                 which defines the `Drop` trait",
-                                b.ty));
+                    span_err!(bccx, move_from.span, E0509,
+                              "cannot move out of type `{}`, \
+                               which defines the `Drop` trait",
+                              b.ty);
                 },
                 _ => {
                     bccx.span_bug(move_from.span, "this path should not cause illegal move")
diff --git a/src/librustc_borrowck/borrowck/mod.rs b/src/librustc_borrowck/borrowck/mod.rs
index 57e578d10c6..4db7974f094 100644
--- a/src/librustc_borrowck/borrowck/mod.rs
+++ b/src/librustc_borrowck/borrowck/mod.rs
@@ -803,6 +803,10 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
         self.tcx.sess.span_err(s, m);
     }
 
+    pub fn span_err_with_code(&self, s: Span, msg: &str, code: &str) {
+        self.tcx.sess.span_err_with_code(s, msg, code);
+    }
+
     pub fn span_bug(&self, s: Span, m: &str) {
         self.tcx.sess.span_bug(s, m);
     }
diff --git a/src/librustc_borrowck/diagnostics.rs b/src/librustc_borrowck/diagnostics.rs
index e94a214309d..a5b313e2dd6 100644
--- a/src/librustc_borrowck/diagnostics.rs
+++ b/src/librustc_borrowck/diagnostics.rs
@@ -263,12 +263,50 @@ fn mutable() {
 You can read more about cell types in the API documentation:
 
 https://doc.rust-lang.org/std/cell/
-"##
+"##,
+
+E0499: r##"
+A variable was borrowed as mutable more than once. Erroneous code example:
+
+```
+let mut i = 0;
+let mut x = &mut i;
+let mut a = &mut i;
+// error: cannot borrow `i` as mutable more than once at a time
+```
+
+Please note that in rust, you can either have many immutable references, or one
+mutable reference. Take a look at
+https://doc.rust-lang.org/stable/book/references-and-borrowing.html for more
+information. Example:
+
+
+```
+let mut i = 0;
+let mut x = &mut i; // ok!
+
+// or:
+let mut i = 0;
+let a = &i; // ok!
+let b = &i; // still ok!
+let c = &i; // still ok!
+```
+"##,
 
 }
 
 register_diagnostics! {
     E0385, // {} in an aliasable location
     E0388, // {} in a static location
-    E0389  // {} in a `&` reference
+    E0389, // {} in a `&` reference
+    E0500, // closure requires unique access to `..` but .. is already borrowed
+    E0501, // cannot borrow `..`.. as .. because previous closure requires unique access
+    E0502, // cannot borrow `..`.. as .. because .. is also borrowed as ...
+    E0503, // cannot use `..` because it was mutably borrowed
+    E0504, // cannot move `..` into closure because it is borrowed
+    E0505, // cannot move out of `..` because it is borrowed
+    E0506, // cannot assign to `..` because it is borrowed
+    E0507, // cannot move out of ..
+    E0508, // cannot move out of type `..`, a non-copy fixed-size array
+    E0509, // cannot move out of type `..`, which defines the `Drop` trait
 }
diff --git a/src/librustc_trans/diagnostics.rs b/src/librustc_trans/diagnostics.rs
new file mode 100644
index 00000000000..dd7c3834e56
--- /dev/null
+++ b/src/librustc_trans/diagnostics.rs
@@ -0,0 +1,21 @@
+// Copyright 2015 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.
+
+#![allow(non_snake_case)]
+
+register_long_diagnostics! {
+
+}
+
+register_diagnostics! {
+    E0510, // invalid use of `return_address` intrinsic: function does not use out pointer
+    E0511, // invalid monomorphization of `{}` intrinsic
+    E0512, // transmute called on types with potentially different sizes...
+}
diff --git a/src/librustc_trans/lib.rs b/src/librustc_trans/lib.rs
index a7fb3af1384..049d8fbe390 100644
--- a/src/librustc_trans/lib.rs
+++ b/src/librustc_trans/lib.rs
@@ -80,6 +80,8 @@ pub mod back {
     pub mod msvc;
 }
 
+pub mod diagnostics;
+
 pub mod trans;
 pub mod save;
 
diff --git a/src/librustc_trans/trans/intrinsic.rs b/src/librustc_trans/trans/intrinsic.rs
index bcfd44d8835..b43a4b3fc88 100644
--- a/src/librustc_trans/trans/intrinsic.rs
+++ b/src/librustc_trans/trans/intrinsic.rs
@@ -44,6 +44,9 @@ use syntax::ast;
 use syntax::ptr::P;
 use syntax::parse::token;
 
+use rustc::session::Session;
+use syntax::codemap::Span;
+
 use std::cmp::Ordering;
 
 pub fn get_simple_intrinsic(ccx: &CrateContext, item: &hir::ForeignItem) -> Option<ValueRef> {
@@ -99,6 +102,10 @@ pub fn get_simple_intrinsic(ccx: &CrateContext, item: &hir::ForeignItem) -> Opti
     Some(ccx.get_intrinsic(&name))
 }
 
+pub fn span_transmute_size_error(a: &Session, b: Span, msg: &str) {
+    span_err!(a, b, E0512, "{}", msg);
+}
+
 /// Performs late verification that intrinsics are used correctly. At present,
 /// the only intrinsic that needs such verification is `transmute`.
 pub fn check_intrinsics(ccx: &CrateContext) {
@@ -127,8 +134,7 @@ pub fn check_intrinsics(ccx: &CrateContext) {
             last_failing_id = Some(transmute_restriction.id);
 
             if transmute_restriction.original_from != transmute_restriction.substituted_from {
-                ccx.sess().span_err(
-                    transmute_restriction.span,
+                span_transmute_size_error(ccx.sess(), transmute_restriction.span,
                     &format!("transmute called on types with potentially different sizes: \
                               {} (could be {} bit{}) to {} (could be {} bit{})",
                              transmute_restriction.original_from,
@@ -138,8 +144,7 @@ pub fn check_intrinsics(ccx: &CrateContext) {
                              to_type_size as usize,
                              if to_type_size == 1 {""} else {"s"}));
             } else {
-                ccx.sess().span_err(
-                    transmute_restriction.span,
+                span_transmute_size_error(ccx.sess(), transmute_restriction.span,
                     &format!("transmute called on types with different sizes: \
                               {} ({} bit{}) to {} ({} bit{})",
                              transmute_restriction.original_from,
@@ -798,9 +803,9 @@ pub fn trans_intrinsic_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
 
         (_, "return_address") => {
             if !fcx.caller_expects_out_pointer {
-                tcx.sess.span_err(call_info.span,
-                                  "invalid use of `return_address` intrinsic: function \
-                                   does not use out pointer");
+                span_err!(tcx.sess, call_info.span, E0510,
+                          "invalid use of `return_address` intrinsic: function \
+                           does not use out pointer");
                 C_null(Type::i8p(ccx))
             } else {
                 PointerCast(bcx, llvm::get_param(fcx.llfn, 0), Type::i8p(ccx))
@@ -1439,6 +1444,10 @@ fn get_rust_try_fn<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>,
     return rust_try
 }
 
+fn span_invalid_monomorphization_error(a: &Session, b: Span, c: &str) {
+    span_err!(a, b, E0511, "{}", c);
+}
+
 fn generic_simd_intrinsic<'blk, 'tcx, 'a>
     (bcx: Block<'blk, 'tcx>,
      name: &str,
@@ -1457,10 +1466,11 @@ fn generic_simd_intrinsic<'blk, 'tcx, 'a>
             emit_error!($msg, )
         };
         ($msg: tt, $($fmt: tt)*) => {
-            bcx.sess().span_err(call_info.span,
-                                &format!(concat!("invalid monomorphization of `{}` intrinsic: ",
-                                                 $msg),
-                                         name, $($fmt)*));
+            span_invalid_monomorphization_error(
+                bcx.sess(), call_info.span,
+                &format!(concat!("invalid monomorphization of `{}` intrinsic: ",
+                                 $msg),
+                         name, $($fmt)*));
         }
     }
     macro_rules! require {