Auto merge of #57747 - Centril:rollup, r=Centril

Rollup of 11 pull requests

Successful merges:

 - #57107 (Add a regression test for mutating a non-mut #[thread_local])
 - #57132 (Document that `-C opt-level=0` implies `-C debug-assertions`.)
 - #57212 (docs(rustc): Link to the book's source in rustc)
 - #57302 (Fix unused_assignments false positive)
 - #57350 (Better error note on unimplemented Index trait for string)
 - #57635 (use structured macro and path resolve suggestions)
 - #57650 (librustc_metadata: Pass a default value when unwrapping a span)
 - #57657 (Add regression test to close #53787)
 - #57658 (Two HIR tweaks)
 - #57720 (Fix suggestions given mulitple bad lifetimes)
 - #57725 (Use structured suggestion to surround struct literal with parenthesis)

Failed merges:

r? @ghost

src/doc/rustc/src/codegen-options/index.md

@@ -187,7 +187,7 @@ This flag lets you control debug information:
 
 This flag lets you control the optimization level.
 
-* `0`: no optimizations
+* `0`: no optimizations, also turn on `cfg(debug_assertions)`.
 * `1`: basic optimizations
 * `2`: some optimizations
 * `3`: all optimizations

src/doc/rustc/src/contributing.md

@@ -1,6 +1,12 @@
 # Contributing to rustc
 
 We'd love to have your help improving `rustc`! To that end, we've written [a
-whole book](https://rust-lang.github.io/rustc-guide/) on its
+whole book][rustc_guide] on its
 internals, how it works, and how to get started working on it. To learn
 more, you'll want to check that out.
+
+If you would like to contribute to _this_ book, you can find its source in the
+rustc source at [src/doc/rustc][rustc_book].
+
+[rustc_guide]: https://rust-lang.github.io/rustc-guide/
+[rustc_book]: https://github.com/rust-lang/rust/tree/master/src/doc/rustc

src/libcore/ops/index.rs

@@ -51,6 +51,21 @@
 /// ```
 #[lang = "index"]
 #[rustc_on_unimplemented(
+    on(
+        _Self="&str",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
+    on(
+        _Self="str",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
+    on(
+        _Self="std::string::String",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
     message="the type `{Self}` cannot be indexed by `{Idx}`",
     label="`{Self}` cannot be indexed by `{Idx}`",
 )]
@@ -141,6 +156,21 @@ pub trait Index<Idx: ?Sized> {
 /// ```
 #[lang = "index_mut"]
 #[rustc_on_unimplemented(
+    on(
+        _Self="&str",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
+    on(
+        _Self="str",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
+    on(
+        _Self="std::string::String",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
     message="the type `{Self}` cannot be mutably indexed by `{Idx}`",
     label="`{Self}` cannot be mutably indexed by `{Idx}`",
 )]

src/librustc/hir/lowering.rs

@@ -3775,7 +3775,7 @@ impl<'a> LoweringContext<'a> {
                 let ohs = P(self.lower_expr(ohs));
                 hir::ExprKind::Unary(op, ohs)
             }
-            ExprKind::Lit(ref l) => hir::ExprKind::Lit(P((*l).clone())),
+            ExprKind::Lit(ref l) => hir::ExprKind::Lit((*l).clone()),
             ExprKind::Cast(ref expr, ref ty) => {
                 let expr = P(self.lower_expr(expr));
                 hir::ExprKind::Cast(expr, self.lower_ty(ty, ImplTraitContext::disallowed()))

src/librustc/hir/mod.rs

@@ -19,7 +19,7 @@ use syntax_pos::{Span, DUMMY_SP, symbol::InternedString};
 use syntax::source_map::{self, Spanned};
 use rustc_target::spec::abi::Abi;
 use syntax::ast::{self, CrateSugar, Ident, Name, NodeId, DUMMY_NODE_ID, AsmDialect};
-use syntax::ast::{Attribute, Lit, StrStyle, FloatTy, IntTy, UintTy};
+use syntax::ast::{Attribute, Label, Lit, StrStyle, FloatTy, IntTy, UintTy};
 use syntax::attr::InlineAttr;
 use syntax::ext::hygiene::SyntaxContext;
 use syntax::ptr::P;
@@ -142,17 +142,6 @@ pub const DUMMY_HIR_ID: HirId = HirId {
 
 pub const DUMMY_ITEM_LOCAL_ID: ItemLocalId = ItemLocalId::MAX;
 
-#[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
-pub struct Label {
-    pub ident: Ident,
-}
-
-impl fmt::Debug for Label {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "label({:?})", self.ident)
-    }
-}
-
 #[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
 pub struct Lifetime {
     pub id: NodeId,
@@ -1466,7 +1455,7 @@ pub enum ExprKind {
     /// A unary operation (For example: `!x`, `*x`)
     Unary(UnOp, P<Expr>),
     /// A literal (For example: `1`, `"foo"`)
-    Lit(P<Lit>),
+    Lit(Lit),
     /// A cast (`foo as f64`)
     Cast(P<Expr>, P<Ty>),
     Type(P<Expr>, P<Ty>),

src/librustc/ich/impls_hir.rs

@@ -153,7 +153,7 @@ impl_stable_hash_for!(enum hir::LifetimeName {
     Error,
 });
 
-impl_stable_hash_for!(struct hir::Label {
+impl_stable_hash_for!(struct ast::Label {
     ident
 });
 

src/librustc/middle/liveness.rs

@@ -911,17 +911,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
     }
 
     fn compute(&mut self, body: &hir::Expr) -> LiveNode {
-        // if there is a `break` or `again` at the top level, then it's
-        // effectively a return---this only occurs in `for` loops,
-        // where the body is really a closure.
-
         debug!("compute: using id for body, {}", self.ir.tcx.hir().node_to_pretty_string(body.id));
 
-        let exit_ln = self.s.exit_ln;
-
-        self.break_ln.insert(body.id, exit_ln);
-        self.cont_ln.insert(body.id, exit_ln);
-
         // the fallthrough exit is only for those cases where we do not
         // explicitly return:
         let s = self.s;
@@ -1024,19 +1015,10 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                 self.propagate_through_expr(&e, succ)
             }
 
-            hir::ExprKind::Closure(.., blk_id, _, _) => {
+            hir::ExprKind::Closure(..) => {
                 debug!("{} is an ExprKind::Closure",
                        self.ir.tcx.hir().node_to_pretty_string(expr.id));
 
-                // The next-node for a break is the successor of the entire
-                // loop. The next-node for a continue is the top of this loop.
-                let node = self.live_node(expr.hir_id, expr.span);
-
-                let break_ln = succ;
-                let cont_ln = node;
-                self.break_ln.insert(blk_id.node_id, break_ln);
-                self.cont_ln.insert(blk_id.node_id, cont_ln);
-
                 // the construction of a closure itself is not important,
                 // but we have to consider the closed over variables.
                 let caps = self.ir.capture_info_map.get(&expr.id).cloned().unwrap_or_else(||
@@ -1407,15 +1389,16 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
         debug!("propagate_through_loop: using id for loop body {} {}",
                expr.id, self.ir.tcx.hir().node_to_pretty_string(body.id));
 
-        let break_ln = succ;
-        let cont_ln = ln;
-        self.break_ln.insert(expr.id, break_ln);
-        self.cont_ln.insert(expr.id, cont_ln);
+
+        self.break_ln.insert(expr.id, succ);
 
         let cond_ln = match kind {
             LoopLoop => ln,
             WhileLoop(ref cond) => self.propagate_through_expr(&cond, ln),
         };
+
+        self.cont_ln.insert(expr.id, cond_ln);
+
         let body_ln = self.propagate_through_block(body, cond_ln);
 
         // repeat until fixed point is reached:

src/librustc_errors/lib.rs

@@ -135,10 +135,11 @@ impl CodeSuggestion {
             if let Some(line) = line_opt {
                 if let Some(lo) = line.char_indices().map(|(i, _)| i).nth(lo) {
                     let hi_opt = hi_opt.and_then(|hi| line.char_indices().map(|(i, _)| i).nth(hi));
-                    buf.push_str(match hi_opt {
-                        Some(hi) => &line[lo..hi],
-                        None => &line[lo..],
-                    });
+                    match hi_opt {
+                        Some(hi) if hi > lo => buf.push_str(&line[lo..hi]),
+                        Some(_) => (),
+                        None => buf.push_str(&line[lo..]),
+                    }
                 }
                 if let None = hi_opt {
                     buf.push('\n');

src/librustc_metadata/native_libs.rs

@@ -163,7 +163,7 @@ impl<'a, 'tcx> Collector<'a, 'tcx> {
            !self.tcx.features().static_nobundle {
             feature_gate::emit_feature_err(&self.tcx.sess.parse_sess,
                                            "static_nobundle",
-                                           span.unwrap(),
+                                           span.unwrap_or_else(|| syntax_pos::DUMMY_SP),
                                            GateIssue::Language,
                                            "kind=\"static-nobundle\" is feature gated");
         }

src/librustc_resolve/lib.rs

@@ -3318,7 +3318,12 @@ impl<'a> Resolver<'a> {
             if let Some(def) = def {
                 match (def, source) {
                     (Def::Macro(..), _) => {
-                        err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
+                        err.span_suggestion_with_applicability(
+                            span,
+                            "use `!` to invoke the macro",
+                            format!("{}!", path_str),
+                            Applicability::MaybeIncorrect,
+                        );
                         return (err, candidates);
                     }
                     (Def::TyAlias(..), PathSource::Trait(_)) => {
@@ -3330,13 +3335,22 @@ impl<'a> Resolver<'a> {
                     }
                     (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
                         ExprKind::Field(_, ident) => {
-                            err.span_label(parent.span, format!("did you mean `{}::{}`?",
-                                                                 path_str, ident));
+                            err.span_suggestion_with_applicability(
+                                parent.span,
+                                "use the path separator to refer to an item",
+                                format!("{}::{}", path_str, ident),
+                                Applicability::MaybeIncorrect,
+                            );
                             return (err, candidates);
                         }
                         ExprKind::MethodCall(ref segment, ..) => {
-                            err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
-                                                                 path_str, segment.ident));
+                            let span = parent.span.with_hi(segment.ident.span.hi());
+                            err.span_suggestion_with_applicability(
+                                span,
+                                "use the path separator to refer to an item",
+                                format!("{}::{}", path_str, segment.ident),
+                                Applicability::MaybeIncorrect,
+                            );
                             return (err, candidates);
                         }
                         _ => {}
@@ -3387,6 +3401,29 @@ impl<'a> Resolver<'a> {
                                 Ok(ref snippet) if snippet == "{" => true,
                                 _ => false,
                             };
+                            // In case this could be a struct literal that needs to be surrounded
+                            // by parenthesis, find the appropriate span.
+                            let mut i = 0;
+                            let mut closing_brace = None;
+                            loop {
+                                sp = sm.next_point(sp);
+                                match sm.span_to_snippet(sp) {
+                                    Ok(ref snippet) => {
+                                        if snippet == "}" {
+                                            let sp = span.to(sp);
+                                            if let Ok(snippet) = sm.span_to_snippet(sp) {
+                                                closing_brace = Some((sp, snippet));
+                                            }
+                                            break;
+                                        }
+                                    }
+                                    _ => break,
+                                }
+                                i += 1;
+                                if i > 100 { // The bigger the span the more likely we're
+                                    break;   // incorrect. Bound it to 100 chars long.
+                                }
+                            }
                             match source {
                                 PathSource::Expr(Some(parent)) => {
                                     match parent.node {
@@ -3413,11 +3450,20 @@ impl<'a> Resolver<'a> {
                                     }
                                 },
                                 PathSource::Expr(None) if followed_by_brace == true => {
-                                    err.span_label(
-                                        span,
-                                        format!("did you mean `({} {{ /* fields */ }})`?",
-                                                path_str),
-                                    );
+                                    if let Some((sp, snippet)) = closing_brace {
+                                        err.span_suggestion_with_applicability(
+                                            sp,
+                                            "surround the struct literal with parenthesis",
+                                            format!("({})", snippet),
+                                            Applicability::MaybeIncorrect,
+                                        );
+                                    } else {
+                                        err.span_label(
+                                            span,
+                                            format!("did you mean `({} {{ /* fields */ }})`?",
+                                                    path_str),
+                                        );
+                                    }
                                     return (err, candidates);
                                 },
                                 _ => {

src/libsyntax/parse/parser.rs

@@ -5234,22 +5234,13 @@ impl<'a> Parser<'a> {
                     kind: ast::GenericParamKind::Lifetime,
                 });
                 if let Some(sp) = seen_ty_param {
-                    let param_span = self.prev_span;
-                    let ate_comma = self.eat(&token::Comma);
-                    let remove_sp = if ate_comma {
-                        param_span.until(self.span)
-                    } else {
-                        last_comma_span.unwrap_or(param_span).to(param_span)
-                    };
-                    bad_lifetime_pos.push(param_span);
-
-                    if let Ok(snippet) = self.sess.source_map().span_to_snippet(param_span) {
+                    let remove_sp = last_comma_span.unwrap_or(self.prev_span).to(self.prev_span);
+                    bad_lifetime_pos.push(self.prev_span);
+                    if let Ok(snippet) = self.sess.source_map().span_to_snippet(self.prev_span) {
                         suggestions.push((remove_sp, String::new()));
-                        suggestions.push((sp.shrink_to_lo(), format!("{}, ", snippet)));
-                    }
-                    if ate_comma {
-                        last_comma_span = Some(self.prev_span);
-                        continue
+                        suggestions.push((
+                            sp.shrink_to_lo(),
+                            format!("{}, ", snippet)));
                     }
                 }
             } else if self.check_ident() {

src/test/ui/error-codes/E0423.stderr

@@ -29,19 +29,25 @@ error[E0423]: expected value, found struct `S`
   --> $DIR/E0423.rs:12:32
    |
 LL |     if let S { x: _x, y: 2 } = S { x: 1, y: 2 } { println!("Ok"); }
-   |                                ^ did you mean `(S { /* fields */ })`?
+   |                                ^---------------
+   |                                |
+   |                                help: surround the struct literal with parenthesis: `(S { x: 1, y: 2 })`
 
 error[E0423]: expected value, found struct `T`
   --> $DIR/E0423.rs:15:8
    |
 LL |     if T {} == T {} { println!("Ok"); }
-   |        ^ did you mean `(T { /* fields */ })`?
+   |        ^---
+   |        |
+   |        help: surround the struct literal with parenthesis: `(T {})`
 
 error[E0423]: expected value, found struct `std::ops::Range`
   --> $DIR/E0423.rs:21:14
    |
 LL |     for _ in std::ops::Range { start: 0, end: 10 } {}
-   |              ^^^^^^^^^^^^^^^ did you mean `(std::ops::Range { /* fields */ })`?
+   |              ^^^^^^^^^^^^^^^----------------------
+   |              |
+   |              help: surround the struct literal with parenthesis: `(std::ops::Range { start: 0, end: 10 })`
 
 error: aborting due to 7 previous errors
 

src/test/ui/feature-gate/feature-gate-static-nobundle-2.rs

@@ -0,0 +1,6 @@
+//~ ERROR kind="static-nobundle" is feature gated
+// Test the behavior of rustc when non-existent library is statically linked
+
+// compile-flags: -l static-nobundle=nonexistent
+
+fn main() {}

src/test/ui/feature-gate/feature-gate-static-nobundle-2.stderr

@@ -0,0 +1,7 @@
+error[E0658]: kind="static-nobundle" is feature gated (see issue #37403)
+   |
+   = help: add #![feature(static_nobundle)] to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/issue-53787-inline-assembler-macro.rs

@@ -0,0 +1,23 @@
+// Regression test for Issue #53787: Fix ICE when creating a label in inline assembler with macros.
+
+#![feature(asm)]
+
+macro_rules! fake_jump {
+    ($id:expr) => {
+        unsafe {
+            asm!(
+            "
+            jmp $0
+            lea eax, [ebx]
+            xor eax, 0xDEADBEEF
+            retn
+            $0:
+            "::"0"($id)::"volatile", "intel");
+        }
+    };
+}
+
+fn main() {
+    fake_jump!("FirstFunc"); //~ ERROR invalid value for constraint in inline assembly
+    println!("Hello, world!");
+}