Auto merge of #41846 - frewsxcv:rollup, r=frewsxcv

Rollup of 8 pull requests

- Successful merges: #41293, #41520, #41827, #41828, #41833, #41836, #41838, #41842
- Failed merges:

src/doc/rustc-ux-guidelines.md

@@ -1,14 +1,14 @@
 % Rustc UX guidelines
 
 Don't forget the user. Whether human or another program, such as an IDE, a
-good user experience with the compiler goes a long way into making developer
-lives better. We don't want users to be baffled by compiler output or
+good user experience with the compiler goes a long way toward making developers'
+lives better. We do not want users to be baffled by compiler output or
 learn arcane patterns to compile their program.
 
 ## Error, Warning, Help, Note Messages
 
-When the compiler detects a problem, it can emit either an error, warning,
-note, or help message.
+When the compiler detects a problem, it can emit one of the following: an error, a warning,
+a note, or a help message.
 
 An `error` is emitted when the compiler detects a problem that makes it unable
  to compile the program, either because the program is invalid or the
@@ -17,11 +17,11 @@ An `error` is emitted when the compiler detects a problem that makes it unable
 A `warning` is emitted when the compiler detects something odd about a
 program. For instance, dead code and unused `Result` values.
 
-A `help` is emitted following either an `error` or `warning` giving extra
+A `help` message is emitted following an `error` or `warning` to give additional
 information to the user about how to solve their problem.
 
-A `note` is for identifying additional circumstances and parts of the code
-that lead to a warning or error. For example, the borrow checker will note any
+A `note` is emitted to identify additional circumstances and parts of the code
+that caused the warning or error. For example, the borrow checker will note any
 previous conflicting borrows.
 
 * Write in plain simple English. If your message, when shown on a – possibly

src/librustc/ty/subst.rs

@@ -102,7 +102,7 @@ impl<'tcx> fmt::Debug for Kind<'tcx> {
         } else if let Some(r) = self.as_region() {
             write!(f, "{:?}", r)
         } else {
-            write!(f, "<unknwon @ {:p}>", self.ptr.get() as *const ())
+            write!(f, "<unknown @ {:p}>", self.ptr.get() as *const ())
         }
     }
 }

src/librustc_errors/lib.rs

@@ -388,6 +388,14 @@ impl Handler {
     pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
         self.emit(&sp.into(), msg, Note);
     }
+    pub fn span_note_diag<'a>(&'a self,
+                              sp: Span,
+                              msg: &str)
+                              -> DiagnosticBuilder<'a> {
+        let mut db = DiagnosticBuilder::new(self, Note, msg);
+        db.set_span(sp);
+        db
+    }
     pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
         self.span_bug(sp, &format!("unimplemented {}", msg));
     }

src/librustc_lint/builtin.rs

@@ -692,6 +692,82 @@ impl EarlyLintPass for DeprecatedAttr {
     }
 }
 
+declare_lint! {
+    pub ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
+    Warn,
+    "floating-point literals cannot be used in patterns"
+}
+
+/// Checks for floating point literals in patterns.
+#[derive(Clone)]
+pub struct IllegalFloatLiteralPattern;
+
+impl LintPass for IllegalFloatLiteralPattern {
+    fn get_lints(&self) -> LintArray {
+        lint_array!(ILLEGAL_FLOATING_POINT_LITERAL_PATTERN)
+    }
+}
+
+fn fl_lit_check_expr(cx: &EarlyContext, expr: &ast::Expr) {
+    use self::ast::{ExprKind, LitKind};
+    match expr.node {
+        ExprKind::Lit(ref l) => {
+            match l.node {
+                LitKind::FloatUnsuffixed(..) |
+                LitKind::Float(..) => {
+                    cx.span_lint(ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
+                                 l.span,
+                                 "floating-point literals cannot be used in patterns");
+                    error!("span mc spanspam");
+                    },
+                _ => (),
+            }
+        }
+        // These may occur in patterns
+        // and can maybe contain float literals
+        ExprKind::Unary(_, ref f) => fl_lit_check_expr(cx, f),
+        // These may occur in patterns
+        // and can't contain float literals
+        ExprKind::Path(..) => (),
+        // If something unhandled is encountered, we need to expand the
+        // search or ignore more ExprKinds.
+        _ => span_bug!(expr.span, "Unhandled expression {:?} in float lit pattern lint",
+                       expr.node),
+    }
+}
+
+impl EarlyLintPass for IllegalFloatLiteralPattern {
+    fn check_pat(&mut self, cx: &EarlyContext, pat: &ast::Pat) {
+        use self::ast::PatKind;
+        pat.walk(&mut |p| {
+            match p.node {
+                // Wildcard patterns and paths are uninteresting for the lint
+                PatKind::Wild |
+                PatKind::Path(..) => (),
+
+                // The walk logic recurses inside these
+                PatKind::Ident(..) |
+                PatKind::Struct(..) |
+                PatKind::Tuple(..) |
+                PatKind::TupleStruct(..) |
+                PatKind::Ref(..) |
+                PatKind::Box(..) |
+                PatKind::Slice(..) => (),
+
+                // Extract the expressions and check them
+                PatKind::Lit(ref e) => fl_lit_check_expr(cx, e),
+                PatKind::Range(ref st, ref en, _) => {
+                    fl_lit_check_expr(cx, st);
+                    fl_lit_check_expr(cx, en);
+                },
+
+                PatKind::Mac(_) => bug!("lint must run post-expansion"),
+            }
+            true
+        });
+    }
+}
+
 declare_lint! {
     pub UNCONDITIONAL_RECURSION,
     Warn,

src/librustc_lint/lib.rs

@@ -113,6 +113,7 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
                        UnusedParens,
                        UnusedImportBraces,
                        AnonymousParameters,
+                       IllegalFloatLiteralPattern,
                        );
 
     add_early_builtin_with_new!(sess,
@@ -201,6 +202,10 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
             id: LintId::of(ILLEGAL_FLOATING_POINT_CONSTANT_PATTERN),
             reference: "issue #36890 <https://github.com/rust-lang/rust/issues/36890>",
         },
+        FutureIncompatibleInfo {
+            id: LintId::of(ILLEGAL_FLOATING_POINT_LITERAL_PATTERN),
+            reference: "issue #41620 <https://github.com/rust-lang/rust/issues/41620>",
+        },
         FutureIncompatibleInfo {
             id: LintId::of(ILLEGAL_STRUCT_OR_ENUM_CONSTANT_PATTERN),
             reference: "issue #36891 <https://github.com/rust-lang/rust/issues/36891>",

src/librustc_save_analysis/Cargo.toml

@@ -14,7 +14,7 @@ rustc = { path = "../librustc" }
 rustc_typeck = { path = "../librustc_typeck" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-rls-data = "0.1"
-rls-span = "0.1"
+rls-data = "0.3"
+rls-span = "0.4"
 # FIXME(#40527) should move rustc serialize out of tree
 rustc-serialize = "0.3"

src/librustc_typeck/check/closure.rs

@@ -126,6 +126,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 (sig, kind)
             }
             ty::TyInfer(ty::TyVar(vid)) => self.deduce_expectations_from_obligations(vid),
+            ty::TyFnPtr(sig) => (Some(sig.skip_binder().clone()), Some(ty::ClosureKind::Fn)),
             _ => (None, None),
         }
     }

src/librustc_typeck/check/method/confirm.rs

@@ -433,22 +433,11 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
         for (i, &expr) in exprs.iter().rev().enumerate() {
             debug!("convert_lvalue_derefs_to_mutable: i={} expr={:?}", i, expr);
 
-            // Fix up the adjustment.
-            let autoderefs = match self.tables.borrow_mut().adjustments.get_mut(&expr.id) {
-                Some(&mut Adjustment {
-                    kind: Adjust::DerefRef { autoderefs, ref mut autoref, .. }, ref mut target
-                }) => {
-                    if let &mut Some(AutoBorrow::Ref(_, ref mut mutbl)) = autoref {
-                        *mutbl = hir::Mutability::MutMutable;
-                        *target = match target.sty {
-                            ty::TyRef(r, ty::TypeAndMut { ty, .. }) =>
-                                self.tcx.mk_ref(r, ty::TypeAndMut { ty, mutbl: *mutbl }),
-                            _ => span_bug!(expr.span, "AutoBorrow::Ref resulted in non-ref {:?}",
-                                           target)
-                        };
-                    }
-                    autoderefs
-                }
+            // Fix up the autoderefs. Autorefs can only occur immediately preceding
+            // overloaded lvalue ops, and will be fixed by them in order to get
+            // the correct region.
+            let autoderefs = match self.tables.borrow().adjustments.get(&expr.id) {
+                Some(&Adjustment { kind: Adjust::DerefRef { autoderefs, .. }, .. }) => autoderefs,
                 Some(_) | None => 0
             };
 
@@ -502,10 +491,35 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
 
         let method = self.try_overloaded_lvalue_op(
             expr.span, None, base_ty, arg_tys, PreferMutLvalue, op);
-        let ok = method.expect("re-trying op failed");
+        let ok = match method {
+            Some(method) => method,
+            None => return self.tcx.sess.delay_span_bug(expr.span, "re-trying op failed")
+        };
         let method = self.register_infer_ok_obligations(ok);
         debug!("convert_lvalue_op_to_mutable: method={:?}", method);
         self.tables.borrow_mut().method_map.insert(method_call, method);
+
+        // Convert the autoref in the base expr to mutable with the correct
+        // region and mutability.
+        if let Some(&mut Adjustment {
+            ref mut target, kind: Adjust::DerefRef {
+                autoref: Some(AutoBorrow::Ref(ref mut r, ref mut mutbl)), ..
+            }
+        }) = self.tables.borrow_mut().adjustments.get_mut(&base_expr.id) {
+            debug!("convert_lvalue_op_to_mutable: converting autoref of {:?}", target);
+
+            // extract method return type, which will be &mut T;
+            // all LB regions should have been instantiated during method lookup
+            let method_sig = self.tcx.no_late_bound_regions(&method.ty.fn_sig()).unwrap();
+
+            *target = method_sig.inputs()[0];
+            if let ty::TyRef(r_, mt) = target.sty {
+                *r = r_;
+                *mutbl = mt.mutbl;
+            } else {
+                span_bug!(expr.span, "input to lvalue op is not a ref?");
+            }
+        }
     }
 
     ///////////////////////////////////////////////////////////////////////////

src/libsyntax/ext/base.rs

@@ -24,6 +24,7 @@ use ptr::P;
 use symbol::Symbol;
 use util::small_vector::SmallVector;
 
+use std::collections::HashMap;
 use std::path::PathBuf;
 use std::rc::Rc;
 use std::default::Default;
@@ -643,6 +644,7 @@ pub struct ExtCtxt<'a> {
     pub resolver: &'a mut Resolver,
     pub resolve_err_count: usize,
     pub current_expansion: ExpansionData,
+    pub expansions: HashMap<Span, Vec<String>>,
 }
 
 impl<'a> ExtCtxt<'a> {
@@ -662,6 +664,7 @@ impl<'a> ExtCtxt<'a> {
                 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
                 directory_ownership: DirectoryOwnership::Owned,
             },
+            expansions: HashMap::new(),
         }
     }
 
@@ -765,6 +768,15 @@ impl<'a> ExtCtxt<'a> {
     pub fn span_bug(&self, sp: Span, msg: &str) -> ! {
         self.parse_sess.span_diagnostic.span_bug(sp, msg);
     }
+    pub fn trace_macros_diag(&self) {
+        for (sp, notes) in self.expansions.iter() {
+            let mut db = self.parse_sess.span_diagnostic.span_note_diag(*sp, &"trace_macro");
+            for note in notes {
+                db.note(&note);
+            }
+            db.emit();
+        }
+    }
     pub fn bug(&self, msg: &str) -> ! {
         self.parse_sess.span_diagnostic.bug(msg);
     }

src/libsyntax/ext/expand.rs

@@ -231,7 +231,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             },
             _ => unreachable!(),
         };
-
+        self.cx.trace_macros_diag();
         krate
     }
 

src/libsyntax/ext/tt/macro_rules.rs

@@ -27,8 +27,8 @@ use symbol::Symbol;
 use tokenstream::{TokenStream, TokenTree};
 
 use std::cell::RefCell;
-use std::collections::{HashMap};
-use std::collections::hash_map::{Entry};
+use std::collections::HashMap;
+use std::collections::hash_map::Entry;
 use std::rc::Rc;
 
 pub struct ParserAnyMacro<'a> {
@@ -85,15 +85,17 @@ impl TTMacroExpander for MacroRulesMacroExpander {
 }
 
 /// Given `lhses` and `rhses`, this is the new macro we create
-fn generic_extension<'cx>(cx: &'cx ExtCtxt,
+fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
                           sp: Span,
                           name: ast::Ident,
                           arg: TokenStream,
                           lhses: &[quoted::TokenTree],
                           rhses: &[quoted::TokenTree])
                           -> Box<MacResult+'cx> {
     if cx.trace_macros() {
-        println!("{}! {{ {} }}", name, arg);
+        let sp = sp.macro_backtrace().last().map(|trace| trace.call_site).unwrap_or(sp);
+        let mut values: &mut Vec<String> = cx.expansions.entry(sp).or_insert(vec![]);
+        values.push(format!("expands to `{}! {{ {} }}`", name, arg));
     }
 
     // Which arm's failure should we report? (the one furthest along)

src/libsyntax/parse/lexer/mod.rs

@@ -504,7 +504,7 @@ impl<'a> StringReader<'a> {
                     self.bump();
 
                     // line comments starting with "///" or "//!" are doc-comments
-                    let doc_comment = self.ch_is('/') || self.ch_is('!');
+                    let doc_comment = (self.ch_is('/') && !self.nextch_is('/')) || self.ch_is('!');
                     let start_bpos = self.pos - BytePos(2);
 
                     while !self.is_eof() {

src/test/compile-fail/closure-no-fn.rs → src/test/compile-fail/closure-no-fn-1.rs

@@ -15,10 +15,4 @@ fn main() {
     let mut a = 0u8;
     let foo: fn(u8) -> u8 = |v: u8| { a += v; a };
     //~^ ERROR mismatched types
-    let b = 0u8;
-    let bar: fn() -> u8 = || { b };
-    //~^ ERROR mismatched types
-    let baz: fn() -> u8 = || { b } as fn() -> u8;
-    //~^ ERROR mismatched types
-    //~^^ ERROR non-scalar cast
 }