Auto merge of #66403 - JohnTitor:rollup-7obuivl, r=JohnTitor

Rollup of 9 pull requests

Successful merges:

 - #66253 (Improve errors after re rebalance coherence)
 - #66264 (fix an ICE in macro's diagnostic message)
 - #66349 (expand source_util macros with def-site context)
 - #66351 (Tweak non-char/numeric in range pattern diagnostic)
 - #66360 (Fix link to Exten in Vec::set_len)
 - #66361 (parser: don't use `unreachable!()` in `fn unexpected`.)
 - #66363 (Improve error message in make_tests)
 - #66369 (compiletest: Obtain timestamps for common inputs only once)
 - #66372 (Fix broken links in Ipv4Addr::is_benchmarking docs)

Failed merges:

r? @ghost

src/liballoc/vec.rs

@@ -861,7 +861,7 @@ impl<T> Vec<T> {
     ///
     /// [`truncate`]: #method.truncate
     /// [`resize`]: #method.resize
-    /// [`extend`]: #method.extend-1
+    /// [`extend`]: ../../std/iter/trait.Extend.html#tymethod.extend
     /// [`clear`]: #method.clear
     ///
     /// # Safety

src/librustc/traits/coherence.rs

@@ -238,7 +238,7 @@ pub fn trait_ref_is_local_or_fundamental<'tcx>(
 
 pub enum OrphanCheckErr<'tcx> {
     NonLocalInputType(Vec<(Ty<'tcx>, bool /* Is this the first input type? */)>),
-    UncoveredTy(Ty<'tcx>),
+    UncoveredTy(Ty<'tcx>, Option<Ty<'tcx>>),
 }
 
 /// Checks the coherence orphan rules. `impl_def_id` should be the
@@ -402,7 +402,15 @@ fn orphan_check_trait_ref<'tcx>(
             return Ok(());
         } else if let ty::Param(_) = input_ty.kind {
             debug!("orphan_check_trait_ref: uncovered ty: `{:?}`", input_ty);
-            return Err(OrphanCheckErr::UncoveredTy(input_ty))
+            let local_type = trait_ref
+                .input_types()
+                .flat_map(|ty| uncover_fundamental_ty(tcx, ty, in_crate))
+                .filter(|ty| ty_is_non_local_constructor(tcx, ty, in_crate).is_none())
+                .next();
+
+            debug!("orphan_check_trait_ref: uncovered ty local_type: `{:?}`", local_type);
+
+            return Err(OrphanCheckErr::UncoveredTy(input_ty, local_type))
         }
         if let Some(non_local_tys) = non_local_tys {
             for input_ty in non_local_tys {

src/librustc_parse/parser/item.rs

@@ -1742,14 +1742,25 @@ impl<'a> Parser<'a> {
     }
 
     fn report_invalid_macro_expansion_item(&self) {
+        let has_close_delim = self.sess.source_map()
+            .span_to_snippet(self.prev_span)
+            .map(|s| s.ends_with(")") || s.ends_with("]"))
+            .unwrap_or(false);
+        let right_brace_span = if has_close_delim {
+            // it's safe to peel off one character only when it has the close delim
+            self.prev_span.with_lo(self.prev_span.hi() - BytePos(1))
+        } else {
+            self.sess.source_map().next_point(self.prev_span)
+        };
+
         self.struct_span_err(
             self.prev_span,
             "macros that expand to items must be delimited with braces or followed by a semicolon",
         ).multipart_suggestion(
             "change the delimiters to curly braces",
             vec![
-                (self.prev_span.with_hi(self.prev_span.lo() + BytePos(1)), String::from(" {")),
-                (self.prev_span.with_lo(self.prev_span.hi() - BytePos(1)), '}'.to_string()),
+                (self.prev_span.with_hi(self.prev_span.lo() + BytePos(1)), "{".to_string()),
+                (right_brace_span, '}'.to_string()),
             ],
             Applicability::MaybeIncorrect,
         ).span_suggestion(

src/librustc_parse/parser/mod.rs

@@ -443,7 +443,9 @@ impl<'a> Parser<'a> {
     crate fn unexpected<T>(&mut self) -> PResult<'a, T> {
         match self.expect_one_of(&[], &[]) {
             Err(e) => Err(e),
-            Ok(_) => unreachable!(),
+            // We can get `Ok(true)` from `recover_closing_delimiter`
+            // which is called in `expected_one_of_not_found`.
+            Ok(_) => FatalError.raise(),
         }
     }
 

src/librustc_typeck/check/pat.rs

@@ -362,37 +362,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             || ty.is_char()
             || ty.references_error()
         };
-        let lhs_compat = numeric_or_char(lhs_ty);
-        let rhs_compat = numeric_or_char(rhs_ty);
-
-        if !lhs_compat || !rhs_compat {
-            let span = if !lhs_compat && !rhs_compat {
-                span
-            } else if !lhs_compat {
-                begin.span
-            } else {
-                end.span
-            };
+        let lhs_fail = !numeric_or_char(lhs_ty);
+        let rhs_fail = !numeric_or_char(rhs_ty);
 
-            let mut err = struct_span_err!(
-                self.tcx.sess,
-                span,
-                E0029,
-                "only char and numeric types are allowed in range patterns"
+        if lhs_fail || rhs_fail {
+            self.emit_err_pat_range(
+                span, begin.span, end.span, lhs_fail, rhs_fail, lhs_ty, rhs_ty
             );
-            err.span_label(span, "ranges require char or numeric types");
-            err.note(&format!("start type: {}", self.ty_to_string(lhs_ty)));
-            err.note(&format!("end type: {}", self.ty_to_string(rhs_ty)));
-            if self.tcx.sess.teach(&err.get_code().unwrap()) {
-                err.note(
-                    "In a match expression, only numbers and characters can be matched \
-                        against a range. This is because the compiler checks that the range \
-                        is non-empty at compile-time, and is unable to evaluate arbitrary \
-                        comparison functions. If you want to capture values of an orderable \
-                        type between two end-points, you can use a guard."
-                    );
-            }
-            err.emit();
             return None;
         }
 
@@ -406,6 +382,62 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         Some(common_type)
     }
 
+    fn emit_err_pat_range(
+        &self,
+        span: Span,
+        begin_span: Span,
+        end_span: Span,
+        lhs_fail: bool,
+        rhs_fail: bool,
+        lhs_ty: Ty<'tcx>,
+        rhs_ty: Ty<'tcx>,
+    ) {
+        let span = if lhs_fail && rhs_fail {
+            span
+        } else if lhs_fail {
+            begin_span
+        } else {
+            end_span
+        };
+
+        let mut err = struct_span_err!(
+            self.tcx.sess,
+            span,
+            E0029,
+            "only char and numeric types are allowed in range patterns"
+        );
+        let msg = |ty| {
+            format!("this is of type `{}` but it should be `char` or numeric", ty)
+        };
+        let mut one_side_err = |first_span, first_ty, second_span, second_ty: Ty<'_>| {
+            err.span_label(first_span, &msg(first_ty));
+            if !second_ty.references_error() {
+                err.span_label(
+                    second_span,
+                    &format!("this is of type `{}`", second_ty)
+                );
+            }
+        };
+        if lhs_fail && rhs_fail {
+            err.span_label(begin_span, &msg(lhs_ty));
+            err.span_label(end_span, &msg(rhs_ty));
+        } else if lhs_fail {
+            one_side_err(begin_span, lhs_ty, end_span, rhs_ty);
+        } else {
+            one_side_err(end_span, rhs_ty, begin_span, lhs_ty);
+        }
+        if self.tcx.sess.teach(&err.get_code().unwrap()) {
+            err.note(
+                "In a match expression, only numbers and characters can be matched \
+                    against a range. This is because the compiler checks that the range \
+                    is non-empty at compile-time, and is unable to evaluate arbitrary \
+                    comparison functions. If you want to capture values of an orderable \
+                    type between two end-points, you can use a guard."
+                );
+        }
+        err.emit();
+    }
+
     fn check_pat_ident(
         &self,
         pat: &Pat,

src/librustc_typeck/coherence/orphan.rs

@@ -77,30 +77,58 @@ impl ItemLikeVisitor<'v> for OrphanChecker<'tcx> {
                     err.emit();
                     return;
                 }
-                Err(traits::OrphanCheckErr::UncoveredTy(param_ty)) => {
+                Err(traits::OrphanCheckErr::UncoveredTy(param_ty, local_type)) => {
                     let mut sp = sp;
                     for param in &generics.params {
                         if param.name.ident().to_string() == param_ty.to_string() {
                             sp = param.span;
                         }
                     }
-                    let mut err = struct_span_err!(
-                        self.tcx.sess,
-                        sp,
-                        E0210,
-                        "type parameter `{}` must be used as the type parameter for some local \
-                         type (e.g., `MyStruct<{}>`)",
-                        param_ty,
-                        param_ty
-                    );
-                    err.span_label(sp, format!(
-                        "type parameter `{}` must be used as the type parameter for some local \
-                         type",
-                        param_ty,
-                    ));
-                    err.note("only traits defined in the current crate can be implemented for a \
-                              type parameter");
-                    err.emit();
+
+                    match local_type {
+                        Some(local_type) => {
+                            struct_span_err!(
+                                self.tcx.sess,
+                                sp,
+                                E0210,
+                                "type parameter `{}` must be covered by another type \
+                                when it appears before the first local type (`{}`)",
+                                param_ty,
+                                local_type
+                            ).span_label(sp, format!(
+                                "type parameter `{}` must be covered by another type \
+                                when it appears before the first local type (`{}`)",
+                                param_ty,
+                                local_type
+                            )).note("implementing a foreign trait is only possible if at \
+                                    least one of the types for which is it implemented is local, \
+                                    and no uncovered type parameters appear before that first \
+                                    local type"
+                            ).note("in this case, 'before' refers to the following order: \
+                                    `impl<..> ForeignTrait<T1, ..., Tn> for T0`, \
+                                    where `T0` is the first and `Tn` is the last"
+                            ).emit();
+                        }
+                        None => {
+                            struct_span_err!(
+                                self.tcx.sess,
+                                sp,
+                                E0210,
+                                "type parameter `{}` must be used as the type parameter for some \
+                                local type (e.g., `MyStruct<{}>`)",
+                                param_ty,
+                                param_ty
+                            ).span_label(sp, format!(
+                                "type parameter `{}` must be used as the type parameter for some \
+                                local type",
+                                param_ty,
+                            )).note("implementing a foreign trait is only possible if at \
+                                    least one of the types for which is it implemented is local"
+                            ).note("only traits defined in the current crate can be \
+                                    implemented for a type parameter"
+                            ).emit();
+                        }
+                    };
                     return;
                 }
             }

src/librustc_typeck/error_codes.rs

@@ -2114,8 +2114,13 @@ E0210: r##"
 This error indicates a violation of one of Rust's orphan rules for trait
 implementations. The rule concerns the use of type parameters in an
 implementation of a foreign trait (a trait defined in another crate), and
-states that type parameters must be "covered" by a local type. To understand
-what this means, it is perhaps easiest to consider a few examples.
+states that type parameters must be "covered" by a local type.
+
+When implementing a foreign trait for a foreign type,
+the trait must have one or more type parameters.
+A type local to your crate must appear before any use of any type parameters.
+
+To understand what this means, it is perhaps easier to consider a few examples.
 
 If `ForeignTrait` is a trait defined in some external crate `foo`, then the
 following trait `impl` is an error:
@@ -2173,12 +2178,18 @@ impl<P1, ..., Pm> ForeignTrait<T1, ..., Tn> for T0 { ... }
 
 where `P1, ..., Pm` are the type parameters of the `impl` and `T0, ..., Tn`
 are types. One of the types `T0, ..., Tn` must be a local type (this is another
-orphan rule, see the explanation for E0117). Let `i` be the smallest integer
-such that `Ti` is a local type. Then no type parameter can appear in any of the
-`Tj` for `j < i`.
+orphan rule, see the explanation for E0117).
 
-For information on the design of the orphan rules, see [RFC 1023].
+Both of the following must be true:
+1. At least one of the types `T0..=Tn` must be a local type.
+Let `Ti` be the first such type.
+2. No uncovered type parameters `P1..=Pm` may appear in `T0..Ti`
+(excluding `Ti`).
+
+For information on the design of the orphan rules,
+see [RFC 2451] and [RFC 1023].
 
+[RFC 2451]: https://rust-lang.github.io/rfcs/2451-re-rebalancing-coherence.html
 [RFC 1023]: https://github.com/rust-lang/rfcs/blob/master/text/1023-rebalancing-coherence.md
 "##,
 

src/libstd/net/ip.rs

@@ -633,8 +633,8 @@ impl Ipv4Addr {
     /// network devices benchmarking. This range is defined in [IETF RFC 2544] as `192.18.0.0`
     /// through `198.19.255.255` but [errata 423] corrects it to `198.18.0.0/15`.
     ///
-    /// [IETF RFC 1112]: https://tools.ietf.org/html/rfc1112
-    /// [errate 423]: https://www.rfc-editor.org/errata/eid423
+    /// [IETF RFC 2544]: https://tools.ietf.org/html/rfc2544
+    /// [errata 423]: https://www.rfc-editor.org/errata/eid423
     /// [`true`]: ../../std/primitive.bool.html
     ///
     /// # Examples

src/libsyntax_ext/source_util.rs

@@ -21,6 +21,7 @@ use rustc_data_structures::sync::Lrc;
 /// line!(): expands to the current line number
 pub fn expand_line(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
                    -> Box<dyn base::MacResult+'static> {
+    let sp = cx.with_def_site_ctxt(sp);
     base::check_zero_tts(cx, sp, tts, "line!");
 
     let topmost = cx.expansion_cause().unwrap_or(sp);
@@ -32,6 +33,7 @@ pub fn expand_line(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
 /* column!(): expands to the current column number */
 pub fn expand_column(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
                   -> Box<dyn base::MacResult+'static> {
+    let sp = cx.with_def_site_ctxt(sp);
     base::check_zero_tts(cx, sp, tts, "column!");
 
     let topmost = cx.expansion_cause().unwrap_or(sp);
@@ -45,6 +47,7 @@ pub fn expand_column(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
 /// out if we wanted.
 pub fn expand_file(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
                    -> Box<dyn base::MacResult+'static> {
+    let sp = cx.with_def_site_ctxt(sp);
     base::check_zero_tts(cx, sp, tts, "file!");
 
     let topmost = cx.expansion_cause().unwrap_or(sp);
@@ -54,12 +57,14 @@ pub fn expand_file(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
 
 pub fn expand_stringify(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
                         -> Box<dyn base::MacResult+'static> {
+    let sp = cx.with_def_site_ctxt(sp);
     let s = pprust::tts_to_string(tts);
     base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&s)))
 }
 
 pub fn expand_mod(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
                   -> Box<dyn base::MacResult+'static> {
+    let sp = cx.with_def_site_ctxt(sp);
     base::check_zero_tts(cx, sp, tts, "module_path!");
     let mod_path = &cx.current_expansion.module.mod_path;
     let string = mod_path.iter().map(|x| x.to_string()).collect::<Vec<String>>().join("::");
@@ -72,6 +77,7 @@ pub fn expand_mod(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
 /// unhygienically.
 pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
                            -> Box<dyn base::MacResult+'cx> {
+    let sp = cx.with_def_site_ctxt(sp);
     let file = match get_single_str_from_tts(cx, sp, tts, "include!") {
         Some(f) => f,
         None => return DummyResult::any(sp),
@@ -125,6 +131,7 @@ pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
 // include_str! : read the given file, insert it as a literal string expr
 pub fn expand_include_str(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
                           -> Box<dyn base::MacResult+'static> {
+    let sp = cx.with_def_site_ctxt(sp);
     let file = match get_single_str_from_tts(cx, sp, tts, "include_str!") {
         Some(f) => f,
         None => return DummyResult::any(sp)
@@ -156,6 +163,7 @@ pub fn expand_include_str(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
 
 pub fn expand_include_bytes(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
                             -> Box<dyn base::MacResult+'static> {
+    let sp = cx.with_def_site_ctxt(sp);
     let file = match get_single_str_from_tts(cx, sp, tts, "include_bytes!") {
         Some(f) => f,
         None => return DummyResult::any(sp)

src/test/ui/coherence/coherence-all-remote.stderr

@@ -4,6 +4,7 @@ error[E0210]: type parameter `T` must be used as the type parameter for some loc
 LL | impl<T> Remote1<T> for isize { }
    |      ^ type parameter `T` must be used as the type parameter for some local type
    |
+   = note: implementing a foreign trait is only possible if at least one of the types for which is it implemented is local
    = note: only traits defined in the current crate can be implemented for a type parameter
 
 error: aborting due to previous error

src/test/ui/coherence/coherence-bigint-param.stderr

@@ -1,10 +1,11 @@
-error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+error[E0210]: type parameter `T` must be covered by another type when it appears before the first local type (`BigInt`)
   --> $DIR/coherence-bigint-param.rs:8:6
    |
 LL | impl<T> Remote1<BigInt> for T { }
-   |      ^ type parameter `T` must be used as the type parameter for some local type
+   |      ^ type parameter `T` must be covered by another type when it appears before the first local type (`BigInt`)
    |
-   = note: only traits defined in the current crate can be implemented for a type parameter
+   = note: implementing a foreign trait is only possible if at least one of the types for which is it implemented is local, and no uncovered type parameters appear before that first local type
+   = note: in this case, 'before' refers to the following order: `impl<..> ForeignTrait<T1, ..., Tn> for T0`, where `T0` is the first and `Tn` is the last
 
 error: aborting due to previous error