Rollup merge of #22764 - ivanradanov:fileline_help, r=huonw

When warnings and errors occur, the associated help message should not print the same code snippet.
https://github.com/rust-lang/rust/issues/21938

src/librustc/metadata/loader.rs

@@ -354,7 +354,7 @@ impl<'a> Context<'a> {
             }
         }
         if self.rejected_via_kind.len() > 0 {
-            self.sess.span_help(self.span, "please recompile this crate using \
+            self.sess.fileline_help(self.span, "please recompile this crate using \
                                             --crate-type lib");
             let mismatches = self.rejected_via_kind.iter();
             for (i, &CrateMismatch { ref path, .. }) in mismatches.enumerate() {

src/librustc/metadata/macro_import.rs

@@ -84,7 +84,7 @@ impl<'a, 'v> Visitor<'v> for MacroLoader<'a> {
                 }
                 "plugin" => {
                     self.sess.span_err(attr.span, "#[plugin] on `extern crate` is deprecated");
-                    self.sess.span_help(attr.span, &format!("use a crate attribute instead, \
+                    self.sess.fileline_help(attr.span, &format!("use a crate attribute instead, \
                                                             i.e. #![plugin({})]",
                                                             item.ident.as_str()));
                 }

src/librustc/middle/check_match.rs

@@ -246,7 +246,7 @@ fn check_for_bindings_named_the_same_as_variants(cx: &MatchCheckCtxt, pat: &Pat)
                                 "pattern binding `{}` is named the same as one \
                                  of the variants of the type `{}`",
                                 &token::get_ident(ident.node), ty_to_string(cx.tcx, pat_ty));
-                            span_help!(cx.tcx.sess, p.span,
+                            fileline_help!(cx.tcx.sess, p.span,
                                 "if you meant to match on a variant, \
                                  consider making the path in the pattern qualified: `{}::{}`",
                                 ty_to_string(cx.tcx, pat_ty), &token::get_ident(ident.node));

src/librustc/middle/infer/error_reporting.rs

@@ -444,7 +444,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
                 // Does the required lifetime have a nice name we can print?
                 span_err!(self.tcx.sess, origin.span(), E0309,
                     "{} may not live long enough", labeled_user_string);
-                self.tcx.sess.span_help(
+                self.tcx.sess.fileline_help(
                     origin.span(),
                     &format!(
                         "consider adding an explicit lifetime bound `{}: {}`...",
@@ -456,7 +456,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
                 // Does the required lifetime have a nice name we can print?
                 span_err!(self.tcx.sess, origin.span(), E0310,
                     "{} may not live long enough", labeled_user_string);
-                self.tcx.sess.span_help(
+                self.tcx.sess.fileline_help(
                     origin.span(),
                     &format!(
                         "consider adding an explicit lifetime bound `{}: 'static`...",
@@ -468,7 +468,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
                 span_err!(self.tcx.sess, origin.span(), E0311,
                         "{} may not live long enough",
                         labeled_user_string);
-                self.tcx.sess.span_help(
+                self.tcx.sess.fileline_help(
                     origin.span(),
                     &format!(
                         "consider adding an explicit lifetime bound for `{}`",

src/librustc_borrowck/borrowck/gather_loans/move_error.rs

@@ -165,7 +165,7 @@ fn note_move_destination(bccx: &BorrowckCtxt,
         bccx.span_note(
             move_to_span,
             "attempting to move value to here");
-        bccx.span_help(
+        bccx.fileline_help(
             move_to_span,
             &format!("to prevent the move, \
                      use `ref {0}` or `ref mut {0}` to capture value by \

src/librustc_borrowck/borrowck/mod.rs

@@ -643,7 +643,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                             ol,
                             moved_lp_msg,
                             pat_ty.user_string(self.tcx)));
-                self.tcx.sess.span_help(span,
+                self.tcx.sess.fileline_help(span,
                     "use `ref` to override");
             }
 
@@ -675,7 +675,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                             moved_lp_msg,
                             expr_ty.user_string(self.tcx),
                             suggestion));
-                self.tcx.sess.span_help(expr_span, help);
+                self.tcx.sess.fileline_help(expr_span, help);
             }
         }
 
@@ -741,6 +741,10 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
         self.tcx.sess.span_help(s, m);
     }
 
+    pub fn fileline_help(&self, s: Span, m: &str) {
+        self.tcx.sess.fileline_help(s, m);
+    }
+
     pub fn bckerr_to_string(&self, err: &BckError<'tcx>) -> String {
         match err.code {
             err_mutbl => {
@@ -870,7 +874,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
         }
 
         if is_closure {
-            self.tcx.sess.span_help(
+            self.tcx.sess.fileline_help(
                 span,
                 "closures behind references must be called via `&mut`");
         }

src/librustc_lint/builtin.rs

@@ -1921,7 +1921,8 @@ impl LintPass for UnconditionalRecursion {
                 for call in &self_call_spans {
                     sess.span_note(*call, "recursive call site")
                 }
-                sess.span_help(sp, "a `loop` may express intention better if this is on purpose")
+                sess.fileline_help(sp, "a `loop` may express intention \
+                                        better if this is on purpose")
             }
         }
 

src/librustc_resolve/lib.rs

@@ -4115,10 +4115,14 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                           uses it like a function name",
                                          path_name));
 
-                        self.session.span_help(expr.span,
-                            &format!("Did you mean to write: \
+                        let msg = format!("Did you mean to write: \
                                            `{} {{ /* fields */ }}`?",
-                                     path_name));
+                                          path_name);
+                        if self.emit_errors {
+                            self.session.fileline_help(expr.span, &msg);
+                        } else {
+                            self.session.span_help(expr.span, &msg);
+                        }
                     } else {
                         // Write the result into the def map.
                         debug!("(resolving expr) resolved `{}`",
@@ -4152,11 +4156,14 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                                 uses it like a function name",
                                                 path_name));
 
-                            self.session.span_help(expr.span,
-                                &format!("Did you mean to write: \
+                                let msg = format!("Did you mean to write: \
                                                      `{} {{ /* fields */ }}`?",
-                                            path_name));
-
+                                                    path_name);
+                                if self.emit_errors {
+                                    self.session.fileline_help(expr.span, &msg);
+                                } else {
+                                    self.session.span_help(expr.span, &msg);
+                                }
                             }
                         _ => {
                             // Keep reporting some errors even if they're ignored above.

src/librustc_trans/trans/foreign.rs

@@ -440,7 +440,7 @@ fn gate_simd_ffi(tcx: &ty::ctxt, decl: &ast::FnDecl, ty: &ty::BareFnTy) {
                               &format!("use of SIMD type `{}` in FFI is highly experimental and \
                                         may result in invalid code",
                                        pprust::ty_to_string(ast_ty)));
-                tcx.sess.span_help(ast_ty.span,
+                tcx.sess.fileline_help(ast_ty.span,
                                    "add #![feature(simd_ffi)] to the crate attributes to enable");
             }
         };

src/librustc_typeck/astconv.rs

@@ -212,18 +212,18 @@ pub fn opt_ast_region_to_region<'tcx>(
                                 }
                             }
                             if len == 1 {
-                                span_help!(this.tcx().sess, default_span,
+                                fileline_help!(this.tcx().sess, default_span,
                                     "this function's return type contains a borrowed value, but \
                                      the signature does not say which {} it is borrowed from",
                                     m);
                             } else if len == 0 {
-                                span_help!(this.tcx().sess, default_span,
+                                fileline_help!(this.tcx().sess, default_span,
                                     "this function's return type contains a borrowed value, but \
                                      there is no value for it to be borrowed from");
-                                span_help!(this.tcx().sess, default_span,
+                                fileline_help!(this.tcx().sess, default_span,
                                     "consider giving it a 'static lifetime");
                             } else {
-                                span_help!(this.tcx().sess, default_span,
+                                fileline_help!(this.tcx().sess, default_span,
                                     "this function's return type contains a borrowed value, but \
                                      the signature does not say whether it is borrowed from {}",
                                     m);
@@ -705,7 +705,7 @@ fn ast_path_to_trait_ref<'a,'tcx>(
                 span_err!(this.tcx().sess, span, E0215,
                                          "angle-bracket notation is not stable when \
                                          used with the `Fn` family of traits, use parentheses");
-                span_help!(this.tcx().sess, span,
+                fileline_help!(this.tcx().sess, span,
                            "add `#![feature(unboxed_closures)]` to \
                             the crate attributes to enable");
             }
@@ -719,7 +719,7 @@ fn ast_path_to_trait_ref<'a,'tcx>(
                 span_err!(this.tcx().sess, span, E0216,
                                          "parenthetical notation is only stable when \
                                          used with the `Fn` family of traits");
-                span_help!(this.tcx().sess, span,
+                fileline_help!(this.tcx().sess, span,
                            "add `#![feature(unboxed_closures)]` to \
                             the crate attributes to enable");
             }
@@ -944,14 +944,14 @@ fn ast_ty_to_trait_ref<'tcx>(this: &AstConv<'tcx>,
                       pprust::ty_to_string(ty));
             match ty.node {
                 ast::TyRptr(None, ref mut_ty) => {
-                    span_help!(this.tcx().sess, ty.span,
+                    fileline_help!(this.tcx().sess, ty.span,
                                "perhaps you meant `&{}({} +{})`? (per RFC 438)",
                                ppaux::mutability_to_string(mut_ty.mutbl),
                                pprust::ty_to_string(&*mut_ty.ty),
                                pprust::bounds_to_string(bounds));
                 }
                ast::TyRptr(Some(ref lt), ref mut_ty) => {
-                    span_help!(this.tcx().sess, ty.span,
+                    fileline_help!(this.tcx().sess, ty.span,
                                "perhaps you meant `&{} {}({} +{})`? (per RFC 438)",
                                pprust::lifetime_to_string(lt),
                                ppaux::mutability_to_string(mut_ty.mutbl),
@@ -960,7 +960,7 @@ fn ast_ty_to_trait_ref<'tcx>(this: &AstConv<'tcx>,
                 }
 
                 _ => {
-                    span_help!(this.tcx().sess, ty.span,
+                    fileline_help!(this.tcx().sess, ty.span,
                                "perhaps you forgot parentheses? (per RFC 438)");
                 }
             }

src/librustc_typeck/check/callee.rs

@@ -63,7 +63,7 @@ pub fn check_legal_trait_for_method_call(ccx: &CrateCtxt, span: Span, trait_id:
         span_err!(tcx.sess, span, E0174,
                   "explicit use of unboxed closure method `{}` is experimental",
                   method);
-        span_help!(tcx.sess, span,
+        fileline_help!(tcx.sess, span,
                    "add `#![feature(unboxed_closures)]` to the crate attributes to enable");
     }
 }

src/librustc_typeck/check/mod.rs

@@ -3098,7 +3098,7 @@ fn check_expr_with_unifier<'a, 'tcx, F>(fcx: &FnCtxt<'a, 'tcx>,
                 },
                 expr_t, None);
 
-            tcx.sess.span_help(field.span,
+            tcx.sess.fileline_help(field.span,
                                "maybe a `()` to call it is missing? \
                                If not, try an anonymous function");
         } else {
@@ -4480,7 +4480,7 @@ pub fn check_instantiable(tcx: &ty::ctxt,
         span_err!(tcx.sess, sp, E0073,
             "this type cannot be instantiated without an \
              instance of itself");
-        span_help!(tcx.sess, sp, "consider using `Option<{}>`",
+        fileline_help!(tcx.sess, sp, "consider using `Option<{}>`",
             ppaux::ty_to_string(tcx, item_ty));
         false
     } else {

src/librustc_typeck/check/wf.rs

@@ -400,7 +400,7 @@ impl<'ccx, 'tcx> CheckTypeWellFormedVisitor<'ccx, 'tcx> {
 
         match suggested_marker_id {
             Some(def_id) => {
-                self.tcx().sess.span_help(
+                self.tcx().sess.fileline_help(
                     span,
                     format!("consider removing `{}` or using a marker such as `{}`",
                             param_name.user_string(self.tcx()),

src/librustc_typeck/coherence/mod.rs

@@ -524,7 +524,7 @@ fn enforce_trait_manually_implementable(tcx: &ty::ctxt, sp: Span, trait_def_id:
         return // everything OK
     };
     span_err!(tcx.sess, sp, E0183, "manual implementations of `{}` are experimental", trait_name);
-    span_help!(tcx.sess, sp,
+    fileline_help!(tcx.sess, sp,
                "add `#![feature(unboxed_closures)]` to the crate attributes to enable");
 }
 

src/librustc_typeck/collect.rs

@@ -1217,7 +1217,7 @@ fn trait_def_of_item<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
             it.span,
             "the `#[rustc_paren_sugar]` attribute is a temporary means of controlling \
              which traits can use parenthetical notation");
-        span_help!(ccx.tcx.sess, it.span,
+        fileline_help!(ccx.tcx.sess, it.span,
                    "add `#![feature(unboxed_closures)]` to \
                     the crate attributes to use it");
     }

src/libsyntax/diagnostics/macros.rs

@@ -52,6 +52,13 @@ macro_rules! span_help {
     })
 }
 
+#[macro_export]
+macro_rules! fileline_help {
+    ($session:expr, $span:expr, $($message:tt)*) => ({
+        ($session).fileline_help($span, &format!($($message)*))
+    })
+}
+
 #[macro_export]
 macro_rules! register_diagnostics {
     ($($code:tt),*) => (

src/libsyntax/ext/base.rs

@@ -753,6 +753,10 @@ impl<'a> ExtCtxt<'a> {
         self.print_backtrace();
         self.parse_sess.span_diagnostic.span_help(sp, msg);
     }
+    pub fn fileline_help(&self, sp: Span, msg: &str) {
+        self.print_backtrace();
+        self.parse_sess.span_diagnostic.fileline_help(sp, msg);
+    }
     pub fn bug(&self, msg: &str) -> ! {
         self.print_backtrace();
         self.parse_sess.span_diagnostic.handler().bug(msg);

src/libsyntax/ext/expand.rs

@@ -571,7 +571,7 @@ fn contains_macro_use(fld: &mut MacroExpander, attrs: &[ast::Attribute]) -> bool
             fld.cx.span_warn(attr.span, "macro_escape is a deprecated synonym for macro_use");
             is_use = true;
             if let ast::AttrInner = attr.node.style {
-                fld.cx.span_help(attr.span, "consider an outer attribute, \
+                fld.cx.fileline_help(attr.span, "consider an outer attribute, \
                                              #[macro_use] mod ...");
             }
         };

src/libsyntax/feature_gate.rs

@@ -362,7 +362,7 @@ impl<'a> Context<'a> {
 
 pub fn emit_feature_err(diag: &SpanHandler, feature: &str, span: Span, explain: &str) {
     diag.span_err(span, explain);
-    diag.span_help(span, &format!("add #![feature({})] to the \
+    diag.fileline_help(span, &format!("add #![feature({})] to the \
                                    crate attributes to enable",
                                   feature));
 }
@@ -370,7 +370,7 @@ pub fn emit_feature_err(diag: &SpanHandler, feature: &str, span: Span, explain:
 pub fn emit_feature_warn(diag: &SpanHandler, feature: &str, span: Span, explain: &str) {
     diag.span_warn(span, explain);
     if diag.handler.can_emit_warnings {
-        diag.span_help(span, &format!("add #![feature({})] to the \
+        diag.fileline_help(span, &format!("add #![feature({})] to the \
                                        crate attributes to silence this warning",
                                       feature));
     }

src/libsyntax/parse/attr.rs

@@ -77,7 +77,7 @@ impl<'a> ParserAttr for Parser<'a> {
                         self.span_err(span,
                                       "an inner attribute is not permitted in \
                                        this context");
-                        self.span_help(span,
+                        self.fileline_help(span,
                                        "place inner attribute at the top of the module or block");
                     }
                     ast::AttrInner

src/libsyntax/parse/lexer/mod.rs

@@ -781,7 +781,7 @@ impl<'a> StringReader<'a> {
         self.span_diagnostic
             .span_warn(sp, "\\U00ABCD12 and \\uABCD escapes are deprecated");
         self.span_diagnostic
-            .span_help(sp, "use \\u{ABCD12} escapes instead");
+            .fileline_help(sp, "use \\u{ABCD12} escapes instead");
     }
 
     /// Scan for a single (possibly escaped) byte or char

src/libsyntax/parse/mod.rs

@@ -724,7 +724,7 @@ pub fn integer_lit(s: &str, suffix: Option<&str>, sd: &SpanHandler, sp: Span) ->
                                               &suf[1..]));
                 } else {
                     sd.span_err(sp, &*format!("illegal suffix `{}` for numeric literal", suf));
-                    sd.span_help(sp, "the suffix must be one of the integral types \
+                    sd.fileline_help(sp, "the suffix must be one of the integral types \
                                       (`u32`, `isize`, etc)");
                 }
 

src/libsyntax/parse/parser.rs

@@ -974,7 +974,7 @@ impl<'a> Parser<'a> {
     }
     pub fn span_fatal_help(&self, sp: Span, m: &str, help: &str) -> ! {
         self.span_err(sp, m);
-        self.span_help(sp, help);
+        self.fileline_help(sp, help);
         panic!(diagnostic::FatalError);
     }
     pub fn span_note(&self, sp: Span, m: &str) {
@@ -983,6 +983,9 @@ impl<'a> Parser<'a> {
     pub fn span_help(&self, sp: Span, m: &str) {
         self.sess.span_diagnostic.span_help(sp, m)
     }
+    pub fn fileline_help(&self, sp: Span, m: &str) {
+        self.sess.span_diagnostic.fileline_help(sp, m)
+    }
     pub fn bug(&self, m: &str) -> ! {
         self.sess.span_diagnostic.span_bug(self.span, m)
     }
@@ -2532,7 +2535,7 @@ impl<'a> Parser<'a> {
                             Some(f) => f,
                             None => continue,
                         };
-                        self.span_help(last_span,
+                        self.fileline_help(last_span,
                             &format!("try parenthesizing the first index; e.g., `(foo.{}){}`",
                                     float.trunc() as usize,
                                     &float.fract().to_string()[1..]));
@@ -2943,7 +2946,7 @@ impl<'a> Parser<'a> {
                 self.span_err(op_span,
                     "chained comparison operators require parentheses");
                 if op.node == BiLt && outer_op == BiGt {
-                    self.span_help(op_span,
+                    self.fileline_help(op_span,
                         "use `::<...>` instead of `<...>` if you meant to specify type arguments");
                 }
             }
@@ -4699,7 +4702,7 @@ impl<'a> Parser<'a> {
         match visa {
             Public => {
                 self.span_err(span, "can't qualify macro invocation with `pub`");
-                self.span_help(span, "try adjusting the macro to put `pub` inside \
+                self.fileline_help(span, "try adjusting the macro to put `pub` inside \
                                       the invocation");
             }
             Inherited => (),
@@ -5445,7 +5448,7 @@ impl<'a> Parser<'a> {
                     if self.token.is_ident() { self.bump(); }
 
                     self.span_err(span, "expected `;`, found `as`");
-                    self.span_help(span,
+                    self.fileline_help(span,
                                    &format!("perhaps you meant to enclose the crate name `{}` in \
                                            a string?",
                                           the_ident.as_str()));
@@ -5756,7 +5759,7 @@ impl<'a> Parser<'a> {
             if self.eat_keyword(keywords::Mut) {
                 let last_span = self.last_span;
                 self.span_err(last_span, "const globals cannot be mutable");
-                self.span_help(last_span, "did you mean to declare a static?");
+                self.fileline_help(last_span, "did you mean to declare a static?");
             }
             let (ident, item_, extra_attrs) = self.parse_item_const(None);
             let last_span = self.last_span;