Rollup of 5 pull requests

src/libcore/macros.rs

@@ -1274,6 +1274,10 @@ pub(crate) mod builtin {
     }
 
     /// Inline assembly.
+    ///
+    /// Read the [unstable book] for the usage.
+    ///
+    /// [unstable book]: ../unstable-book/library-features/asm.html
     #[unstable(feature = "asm", issue = "29722",
                reason = "inline assembly is not stable enough for use and is subject to change")]
     #[rustc_builtin_macro]

src/libfmt_macros/lib.rs

@@ -35,7 +35,7 @@ impl InnerOffset {
 
 /// A piece is a portion of the format string which represents the next part
 /// to emit. These are emitted as a stream by the `Parser` class.
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub enum Piece<'a> {
     /// A literal string which should directly be emitted
     String(&'a str),
@@ -45,7 +45,7 @@ pub enum Piece<'a> {
 }
 
 /// Representation of an argument specification.
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub struct Argument<'a> {
     /// Where to find this argument
     pub position: Position,
@@ -54,7 +54,7 @@ pub struct Argument<'a> {
 }
 
 /// Specification for the formatting of an argument in the format string.
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub struct FormatSpec<'a> {
     /// Optionally specified character to fill alignment with.
     pub fill: Option<char>,
@@ -74,10 +74,12 @@ pub struct FormatSpec<'a> {
     /// this argument, this can be empty or any number of characters, although
     /// it is required to be one word.
     pub ty: &'a str,
+    /// The span of the descriptor string (for diagnostics).
+    pub ty_span: Option<InnerSpan>,
 }
 
 /// Enum describing where an argument for a format can be located.
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub enum Position {
     /// The argument is implied to be located at an index
     ArgumentImplicitlyIs(usize),
@@ -97,7 +99,7 @@ impl Position {
 }
 
 /// Enum of alignments which are supported.
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub enum Alignment {
     /// The value will be aligned to the left.
     AlignLeft,
@@ -111,7 +113,7 @@ pub enum Alignment {
 
 /// Various flags which can be applied to format strings. The meaning of these
 /// flags is defined by the formatters themselves.
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub enum Flag {
     /// A `+` will be used to denote positive numbers.
     FlagSignPlus,
@@ -131,7 +133,7 @@ pub enum Flag {
 
 /// A count is used for the precision and width parameters of an integer, and
 /// can reference either an argument or a literal integer.
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub enum Count {
     /// The count is specified explicitly.
     CountIs(usize),
@@ -475,6 +477,7 @@ impl<'a> Parser<'a> {
             width: CountImplied,
             width_span: None,
             ty: &self.input[..0],
+            ty_span: None,
         };
         if !self.consume(':') {
             return spec;
@@ -548,6 +551,7 @@ impl<'a> Parser<'a> {
                 spec.precision_span = sp;
             }
         }
+        let ty_span_start = self.cur.peek().map(|(pos, _)| *pos);
         // Optional radix followed by the actual format specifier
         if self.consume('x') {
             if self.consume('?') {
@@ -567,6 +571,12 @@ impl<'a> Parser<'a> {
             spec.ty = "?";
         } else {
             spec.ty = self.word();
+            let ty_span_end = self.cur.peek().map(|(pos, _)| *pos);
+            if !spec.ty.is_empty() {
+                spec.ty_span = ty_span_start
+                    .and_then(|s| ty_span_end.map(|e| (s, e)))
+                    .map(|(start, end)| self.to_span_index(start).to(self.to_span_index(end)));
+            }
         }
         spec
     }

src/libfmt_macros/tests.rs

@@ -2,7 +2,7 @@ use super::*;
 
 fn same(fmt: &'static str, p: &[Piece<'static>]) {
     let parser = Parser::new(fmt, None, vec![], false);
-    assert!(parser.collect::<Vec<Piece<'static>>>() == p);
+    assert_eq!(parser.collect::<Vec<Piece<'static>>>(), p);
 }
 
 fn fmtdflt() -> FormatSpec<'static> {
@@ -15,6 +15,7 @@ fn fmtdflt() -> FormatSpec<'static> {
         precision_span: None,
         width_span: None,
         ty: "",
+        ty_span: None,
     };
 }
 
@@ -82,7 +83,7 @@ fn format_position_nothing_else() {
 #[test]
 fn format_type() {
     same(
-        "{3:a}",
+        "{3:x}",
         &[NextArgument(Argument {
             position: ArgumentIs(3),
             format: FormatSpec {
@@ -93,7 +94,8 @@ fn format_type() {
                 width: CountImplied,
                 precision_span: None,
                 width_span: None,
-                ty: "a",
+                ty: "x",
+                ty_span: None,
             },
         })]);
 }
@@ -112,6 +114,7 @@ fn format_align_fill() {
                 precision_span: None,
                 width_span: None,
                 ty: "",
+                ty_span: None,
             },
         })]);
     same(
@@ -127,6 +130,7 @@ fn format_align_fill() {
                 precision_span: None,
                 width_span: None,
                 ty: "",
+                ty_span: None,
             },
         })]);
     same(
@@ -142,6 +146,7 @@ fn format_align_fill() {
                 precision_span: None,
                 width_span: None,
                 ty: "abcd",
+                ty_span: Some(InnerSpan::new(6, 10)),
             },
         })]);
 }
@@ -150,7 +155,7 @@ fn format_counts() {
     use syntax_pos::{GLOBALS, Globals, edition};
     GLOBALS.set(&Globals::new(edition::DEFAULT_EDITION), || {
     same(
-        "{:10s}",
+        "{:10x}",
         &[NextArgument(Argument {
             position: ArgumentImplicitlyIs(0),
             format: FormatSpec {
@@ -161,11 +166,12 @@ fn format_counts() {
                 width: CountIs(10),
                 precision_span: None,
                 width_span: None,
-                ty: "s",
+                ty: "x",
+                ty_span: None,
             },
         })]);
     same(
-        "{:10$.10s}",
+        "{:10$.10x}",
         &[NextArgument(Argument {
             position: ArgumentImplicitlyIs(0),
             format: FormatSpec {
@@ -176,11 +182,12 @@ fn format_counts() {
                 width: CountIsParam(10),
                 precision_span: None,
                 width_span: Some(InnerSpan::new(3, 6)),
-                ty: "s",
+                ty: "x",
+                ty_span: None,
             },
         })]);
     same(
-        "{:.*s}",
+        "{:.*x}",
         &[NextArgument(Argument {
             position: ArgumentImplicitlyIs(1),
             format: FormatSpec {
@@ -191,11 +198,12 @@ fn format_counts() {
                 width: CountImplied,
                 precision_span: Some(InnerSpan::new(3, 5)),
                 width_span: None,
-                ty: "s",
+                ty: "x",
+                ty_span: None,
             },
         })]);
     same(
-        "{:.10$s}",
+        "{:.10$x}",
         &[NextArgument(Argument {
             position: ArgumentImplicitlyIs(0),
             format: FormatSpec {
@@ -206,11 +214,12 @@ fn format_counts() {
                 width: CountImplied,
                 precision_span: Some(InnerSpan::new(3, 7)),
                 width_span: None,
-                ty: "s",
+                ty: "x",
+                ty_span: None,
             },
         })]);
     same(
-        "{:a$.b$s}",
+        "{:a$.b$?}",
         &[NextArgument(Argument {
             position: ArgumentImplicitlyIs(0),
             format: FormatSpec {
@@ -221,7 +230,8 @@ fn format_counts() {
                 width: CountIsName(Symbol::intern("a")),
                 precision_span: None,
                 width_span: None,
-                ty: "s",
+                ty: "?",
+                ty_span: None,
             },
         })]);
     });
@@ -241,6 +251,7 @@ fn format_flags() {
                 precision_span: None,
                 width_span: None,
                 ty: "",
+                ty_span: None,
             },
         })]);
     same(
@@ -256,13 +267,14 @@ fn format_flags() {
                 precision_span: None,
                 width_span: None,
                 ty: "",
+                ty_span: None,
             },
         })]);
 }
 #[test]
 fn format_mixture() {
     same(
-        "abcd {3:a} efg",
+        "abcd {3:x} efg",
         &[
             String("abcd "),
             NextArgument(Argument {
@@ -275,7 +287,8 @@ fn format_mixture() {
                     width: CountImplied,
                     precision_span: None,
                     width_span: None,
-                    ty: "a",
+                    ty: "x",
+                    ty_span: None,
                 },
             }),
             String(" efg"),

src/librustc/hir/lowering.rs

@@ -2120,6 +2120,16 @@ impl<'a> LoweringContext<'a> {
         impl_trait_return_allow: bool,
         make_ret_async: Option<NodeId>,
     ) -> P<hir::FnDecl> {
+        debug!("lower_fn_decl(\
+            fn_decl: {:?}, \
+            in_band_ty_params: {:?}, \
+            impl_trait_return_allow: {}, \
+            make_ret_async: {:?})",
+            decl,
+            in_band_ty_params,
+            impl_trait_return_allow,
+            make_ret_async,
+        );
         let lt_mode = if make_ret_async.is_some() {
             // In `async fn`, argument-position elided lifetimes
             // must be transformed into fresh generic parameters so that
@@ -2412,7 +2422,7 @@ impl<'a> LoweringContext<'a> {
 
         hir::FunctionRetTy::Return(P(hir::Ty {
             kind: opaque_ty_ref,
-            span,
+            span: opaque_ty_span,
             hir_id: self.next_id(),
         }))
     }
@@ -2522,7 +2532,7 @@ impl<'a> LoweringContext<'a> {
         hir::Lifetime {
             hir_id: self.lower_node_id(id),
             span,
-            name: name,
+            name,
         }
     }
 

src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs

@@ -43,7 +43,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     ///
     /// It will later be extended to trait objects.
     pub(super) fn try_report_anon_anon_conflict(&self) -> Option<ErrorReported> {
-        let (span, sub, sup) = self.get_regions();
+        let (span, sub, sup) = self.regions();
 
         // Determine whether the sub and sup consist of both anonymous (elided) regions.
         let anon_reg_sup = self.tcx().is_suitable_region(sup)?;

src/librustc/infer/error_reporting/nice_region_error/mod.rs

@@ -77,7 +77,7 @@ impl<'cx, 'tcx> NiceRegionError<'cx, 'tcx> {
             .or_else(|| self.try_report_impl_not_conforming_to_trait())
     }
 
-    pub fn get_regions(&self) -> (Span, ty::Region<'tcx>, ty::Region<'tcx>) {
+    pub fn regions(&self) -> (Span, ty::Region<'tcx>, ty::Region<'tcx>) {
         match (&self.error, self.regions) {
             (Some(ConcreteFailure(origin, sub, sup)), None) => (origin.span(), sub, sup),
             (Some(SubSupConflict(_, _, origin, sub, _, sup)), None) => (origin.span(), sub, sup),

src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs

@@ -9,7 +9,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// When given a `ConcreteFailure` for a function with parameters containing a named region and
     /// an anonymous region, emit an descriptive diagnostic error.
     pub(super) fn try_report_named_anon_conflict(&self) -> Option<DiagnosticBuilder<'a>> {
-        let (span, sub, sup) = self.get_regions();
+        let (span, sub, sup) = self.regions();
 
         debug!(
             "try_report_named_anon_conflict(sub={:?}, sup={:?}, error={:?})",

src/librustc/infer/error_reporting/nice_region_error/static_impl_trait.rs

@@ -20,8 +20,9 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
                 ) = error.clone()
             {
                 let anon_reg_sup = self.tcx().is_suitable_region(sup_r)?;
+                let return_ty = self.tcx().return_type_impl_trait(anon_reg_sup.def_id);
                 if sub_r == &RegionKind::ReStatic &&
-                    self.tcx().return_type_impl_trait(anon_reg_sup.def_id).is_some()
+                    return_ty.is_some()
                 {
                     let sp = var_origin.span();
                     let return_sp = sub_origin.span();
@@ -52,17 +53,23 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
                         }) => name.to_string(),
                         _ => "'_".to_owned(),
                     };
-                    if let Ok(snippet) = self.tcx().sess.source_map().span_to_snippet(return_sp) {
-                        err.span_suggestion(
-                            return_sp,
-                            &format!(
-                                "you can add a constraint to the return type to make it last \
+                    let fn_return_span = return_ty.unwrap().1;
+                    if let Ok(snippet) =
+                        self.tcx().sess.source_map().span_to_snippet(fn_return_span) {
+                        // only apply this suggestion onto functions with
+                        // explicit non-desugar'able return.
+                        if fn_return_span.desugaring_kind().is_none() {
+                            err.span_suggestion(
+                                fn_return_span,
+                                &format!(
+                                    "you can add a constraint to the return type to make it last \
                                  less than `'static` and match {}",
-                                lifetime,
-                            ),
-                            format!("{} + {}", snippet, lifetime_name),
-                            Applicability::Unspecified,
-                        );
+                                 lifetime,
+                                ),
+                                format!("{} + {}", snippet, lifetime_name),
+                                Applicability::Unspecified,
+                            );
+                        }
                     }
                     err.emit();
                     return Some(ErrorReported);