Rollup of 6 pull requests

compiler/rustc_incremental/src/persist/load.rs

@@ -6,6 +6,7 @@ use rustc_middle::dep_graph::{SerializedDepGraph, WorkProduct, WorkProductId};
 use rustc_middle::ty::OnDiskCache;
 use rustc_serialize::opaque::Decoder;
 use rustc_serialize::Decodable;
+use rustc_session::config::IncrementalStateAssertion;
 use rustc_session::Session;
 use std::path::Path;
 
@@ -16,6 +17,7 @@ use super::work_product;
 
 type WorkProductMap = FxHashMap<WorkProductId, WorkProduct>;
 
+#[derive(Debug)]
 pub enum LoadResult<T> {
     Ok { data: T },
     DataOutOfDate,
@@ -24,6 +26,26 @@ pub enum LoadResult<T> {
 
 impl<T: Default> LoadResult<T> {
     pub fn open(self, sess: &Session) -> T {
+        // Check for errors when using `-Zassert-incremental-state`
+        match (sess.opts.assert_incr_state, &self) {
+            (Some(IncrementalStateAssertion::NotLoaded), LoadResult::Ok { .. }) => {
+                sess.fatal(
+                    "We asserted that the incremental cache should not be loaded, \
+                         but it was loaded.",
+                );
+            }
+            (
+                Some(IncrementalStateAssertion::Loaded),
+                LoadResult::Error { .. } | LoadResult::DataOutOfDate,
+            ) => {
+                sess.fatal(
+                    "We asserted that an existing incremental cache directory should \
+                         be successfully loaded, but it was not.",
+                );
+            }
+            _ => {}
+        };
+
         match self {
             LoadResult::Error { message } => {
                 sess.warn(&message);
@@ -33,7 +55,7 @@ impl<T: Default> LoadResult<T> {
                 if let Err(err) = delete_all_session_dir_contents(sess) {
                     sess.err(&format!(
                         "Failed to delete invalidated or incompatible \
-                                      incremental compilation session directory contents `{}`: {}.",
+                         incremental compilation session directory contents `{}`: {}.",
                         dep_graph_path(sess).display(),
                         err
                     ));

compiler/rustc_interface/src/tests.rs

@@ -636,6 +636,7 @@ fn test_debugging_options_tracking_hash() {
 
     // Make sure that changing an [UNTRACKED] option leaves the hash unchanged.
     // This list is in alphabetical order.
+    untracked!(assert_incr_state, Some(String::from("loaded")));
     untracked!(ast_json, true);
     untracked!(ast_json_noexpand, true);
     untracked!(borrowck, String::from("other"));

compiler/rustc_session/src/config.rs

@@ -165,6 +165,18 @@ pub enum LinkerPluginLto {
     Disabled,
 }
 
+/// Used with `-Z assert-incr-state`.
+#[derive(Clone, Copy, PartialEq, Hash, Debug)]
+pub enum IncrementalStateAssertion {
+    /// Found and loaded an existing session directory.
+    ///
+    /// Note that this says nothing about whether any particular query
+    /// will be found to be red or green.
+    Loaded,
+    /// Did not load an existing session directory.
+    NotLoaded,
+}
+
 impl LinkerPluginLto {
     pub fn enabled(&self) -> bool {
         match *self {
@@ -704,6 +716,7 @@ pub fn host_triple() -> &'static str {
 impl Default for Options {
     fn default() -> Options {
         Options {
+            assert_incr_state: None,
             crate_types: Vec::new(),
             optimize: OptLevel::No,
             debuginfo: DebugInfo::None,
@@ -1626,6 +1639,21 @@ fn select_debuginfo(
     }
 }
 
+crate fn parse_assert_incr_state(
+    opt_assertion: &Option<String>,
+    error_format: ErrorOutputType,
+) -> Option<IncrementalStateAssertion> {
+    match opt_assertion {
+        Some(s) if s.as_str() == "loaded" => Some(IncrementalStateAssertion::Loaded),
+        Some(s) if s.as_str() == "not-loaded" => Some(IncrementalStateAssertion::NotLoaded),
+        Some(s) => early_error(
+            error_format,
+            &format!("unexpected incremental state assertion value: {}", s),
+        ),
+        None => None,
+    }
+}
+
 fn parse_native_lib_kind(
     matches: &getopts::Matches,
     kind: &str,
@@ -2015,6 +2043,9 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
 
     let incremental = cg.incremental.as_ref().map(PathBuf::from);
 
+    let assert_incr_state =
+        parse_assert_incr_state(&debugging_opts.assert_incr_state, error_format);
+
     if debugging_opts.profile && incremental.is_some() {
         early_error(
             error_format,
@@ -2179,6 +2210,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
     };
 
     Options {
+        assert_incr_state,
         crate_types,
         optimize: opt_level,
         debuginfo,

compiler/rustc_session/src/options.rs

@@ -4,7 +4,6 @@ use crate::early_error;
 use crate::lint;
 use crate::search_paths::SearchPath;
 use crate::utils::NativeLib;
-
 use rustc_target::spec::{CodeModel, LinkerFlavor, MergeFunctions, PanicStrategy, SanitizerSet};
 use rustc_target::spec::{RelocModel, RelroLevel, SplitDebuginfo, TargetTriple, TlsModel};
 
@@ -150,6 +149,7 @@ top_level_options!(
         /// If `Some`, enable incremental compilation, using the given
         /// directory to store intermediate results.
         incremental: Option<PathBuf> [UNTRACKED],
+        assert_incr_state: Option<IncrementalStateAssertion> [UNTRACKED],
 
         debugging_opts: DebuggingOptions [SUBSTRUCT],
         prints: Vec<PrintRequest> [UNTRACKED],
@@ -1046,6 +1046,9 @@ options! {
         "make cfg(version) treat the current version as incomplete (default: no)"),
     asm_comments: bool = (false, parse_bool, [TRACKED],
         "generate comments into the assembly (may change behavior) (default: no)"),
+    assert_incr_state: Option<String> = (None, parse_opt_string, [UNTRACKED],
+        "assert that the incremental cache is in given state: \
+         either `loaded` or `not-loaded`."),
     ast_json: bool = (false, parse_bool, [UNTRACKED],
         "print the AST as JSON and halt (default: no)"),
     ast_json_noexpand: bool = (false, parse_bool, [UNTRACKED],

compiler/rustc_typeck/src/check/method/suggest.rs

@@ -317,14 +317,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                     .span_to_snippet(lit.span)
                                     .unwrap_or_else(|_| "<numeric literal>".to_owned());
 
+                                // If this is a floating point literal that ends with '.',
+                                // get rid of it to stop this from becoming a member access.
+                                let snippet = snippet.strip_suffix('.').unwrap_or(&snippet);
+
                                 err.span_suggestion(
                                     lit.span,
                                     &format!(
                                         "you must specify a concrete type for this numeric value, \
                                          like `{}`",
                                         concrete_type
                                     ),
-                                    format!("{}_{}", snippet, concrete_type),
+                                    format!("{snippet}_{concrete_type}"),
                                     Applicability::MaybeIncorrect,
                                 );
                             }

library/alloc/src/vec/mod.rs

@@ -1272,6 +1272,9 @@ impl<T, A: Allocator> Vec<T, A> {
     /// The removed element is replaced by the last element of the vector.
     ///
     /// This does not preserve ordering, but is *O*(1).
+    /// If you need to preserve the element order, use [`remove`] instead.
+    ///
+    /// [`remove`]: Vec::remove
     ///
     /// # Panics
     ///
@@ -1368,7 +1371,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// shifting all elements after it to the left.
     ///
     /// Note: Because this shifts over the remaining elements, it has a
-    /// worst-case performance of O(n). If you don't need the order of elements
+    /// worst-case performance of *O*(*n*). If you don't need the order of elements
     /// to be preserved, use [`swap_remove`] instead.
     ///
     /// [`swap_remove`]: Vec::swap_remove

library/alloc/tests/lib.rs

@@ -25,6 +25,7 @@
 #![feature(const_btree_new)]
 #![feature(const_default_impls)]
 #![feature(const_trait_impl)]
+#![feature(const_str_from_utf8)]
 
 use std::collections::hash_map::DefaultHasher;
 use std::hash::{Hash, Hasher};

library/alloc/tests/str.rs

@@ -1,3 +1,4 @@
+use std::assert_matches::assert_matches;
 use std::borrow::Cow;
 use std::cmp::Ordering::{Equal, Greater, Less};
 use std::str::{from_utf8, from_utf8_unchecked};
@@ -883,6 +884,33 @@ fn test_is_utf8() {
     assert!(from_utf8(&[0xF4, 0x8F, 0xBF, 0xBF]).is_ok());
 }
 
+#[test]
+fn test_const_is_utf8() {
+    const _: () = {
+        // deny overlong encodings
+        assert!(from_utf8(&[0xc0, 0x80]).is_err());
+        assert!(from_utf8(&[0xc0, 0xae]).is_err());
+        assert!(from_utf8(&[0xe0, 0x80, 0x80]).is_err());
+        assert!(from_utf8(&[0xe0, 0x80, 0xaf]).is_err());
+        assert!(from_utf8(&[0xe0, 0x81, 0x81]).is_err());
+        assert!(from_utf8(&[0xf0, 0x82, 0x82, 0xac]).is_err());
+        assert!(from_utf8(&[0xf4, 0x90, 0x80, 0x80]).is_err());
+
+        // deny surrogates
+        assert!(from_utf8(&[0xED, 0xA0, 0x80]).is_err());
+        assert!(from_utf8(&[0xED, 0xBF, 0xBF]).is_err());
+
+        assert!(from_utf8(&[0xC2, 0x80]).is_ok());
+        assert!(from_utf8(&[0xDF, 0xBF]).is_ok());
+        assert!(from_utf8(&[0xE0, 0xA0, 0x80]).is_ok());
+        assert!(from_utf8(&[0xED, 0x9F, 0xBF]).is_ok());
+        assert!(from_utf8(&[0xEE, 0x80, 0x80]).is_ok());
+        assert!(from_utf8(&[0xEF, 0xBF, 0xBF]).is_ok());
+        assert!(from_utf8(&[0xF0, 0x90, 0x80, 0x80]).is_ok());
+        assert!(from_utf8(&[0xF4, 0x8F, 0xBF, 0xBF]).is_ok());
+    };
+}
+
 #[test]
 fn from_utf8_mostly_ascii() {
     // deny invalid bytes embedded in long stretches of ascii
@@ -895,13 +923,43 @@ fn from_utf8_mostly_ascii() {
     }
 }
 
+#[test]
+fn const_from_utf8_mostly_ascii() {
+    const _: () = {
+        // deny invalid bytes embedded in long stretches of ascii
+        let mut i = 32;
+        while i < 64 {
+            let mut data = [0; 128];
+            data[i] = 0xC0;
+            assert!(from_utf8(&data).is_err());
+            data[i] = 0xC2;
+            assert!(from_utf8(&data).is_err());
+
+            i = i + 1;
+        }
+    };
+}
+
 #[test]
 fn from_utf8_error() {
     macro_rules! test {
-        ($input: expr, $expected_valid_up_to: expr, $expected_error_len: expr) => {
+        ($input: expr, $expected_valid_up_to:pat, $expected_error_len:pat) => {
             let error = from_utf8($input).unwrap_err();
-            assert_eq!(error.valid_up_to(), $expected_valid_up_to);
-            assert_eq!(error.error_len(), $expected_error_len);
+            assert_matches!(error.valid_up_to(), $expected_valid_up_to);
+            assert_matches!(error.error_len(), $expected_error_len);
+
+            const _: () = {
+                match from_utf8($input) {
+                    Err(error) => {
+                        let valid_up_to = error.valid_up_to();
+                        let error_len = error.error_len();
+
+                        assert!(matches!(valid_up_to, $expected_valid_up_to));
+                        assert!(matches!(error_len, $expected_error_len));
+                    }
+                    Ok(_) => unreachable!(),
+                }
+            };
         };
     }
     test!(b"A\xC3\xA9 \xFF ", 4, Some(1));

library/core/src/lib.rs

@@ -97,6 +97,7 @@
 #![allow(explicit_outlives_requirements)]
 //
 // Library features for const fns:
+#![feature(const_align_offset)]
 #![feature(const_align_of_val)]
 #![feature(const_alloc_layout)]
 #![feature(const_arguments_as_str)]
@@ -130,6 +131,7 @@
 #![feature(const_size_of_val)]
 #![feature(const_slice_from_raw_parts)]
 #![feature(const_slice_ptr_len)]
+#![feature(const_str_from_utf8_unchecked_mut)]
 #![feature(const_swap)]
 #![feature(const_trait_impl)]
 #![feature(const_type_id)]
@@ -138,6 +140,7 @@
 #![feature(duration_consts_2)]
 #![feature(ptr_metadata)]
 #![feature(slice_ptr_get)]
+#![feature(str_internals)]
 #![feature(variant_count)]
 #![feature(const_array_from_ref)]
 #![feature(const_slice_from_ref)]

library/core/src/str/converts.rs

@@ -82,10 +82,16 @@ use super::Utf8Error;
 /// assert_eq!("💖", sparkle_heart);
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
-pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error> {
-    run_utf8_validation(v)?;
-    // SAFETY: Just ran validation.
-    Ok(unsafe { from_utf8_unchecked(v) })
+#[rustc_const_unstable(feature = "const_str_from_utf8", issue = "91006")]
+pub const fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error> {
+    // This should use `?` again, once it's `const`
+    match run_utf8_validation(v) {
+        Ok(_) => {
+            // SAFETY: validation succeeded.
+            Ok(unsafe { from_utf8_unchecked(v) })
+        }
+        Err(err) => Err(err),
+    }
 }
 
 /// Converts a mutable slice of bytes to a mutable string slice.
@@ -119,10 +125,16 @@ pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error> {
 /// See the docs for [`Utf8Error`] for more details on the kinds of
 /// errors that can be returned.
 #[stable(feature = "str_mut_extras", since = "1.20.0")]
-pub fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error> {
-    run_utf8_validation(v)?;
-    // SAFETY: Just ran validation.
-    Ok(unsafe { from_utf8_unchecked_mut(v) })
+#[rustc_const_unstable(feature = "const_str_from_utf8", issue = "91006")]
+pub const fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error> {
+    // This should use `?` again, once it's `const`
+    match run_utf8_validation(v) {
+        Ok(_) => {
+            // SAFETY: validation succeeded.
+            Ok(unsafe { from_utf8_unchecked_mut(v) })
+        }
+        Err(err) => Err(err),
+    }
 }
 
 /// Converts a slice of bytes to a string slice without checking
@@ -184,7 +196,8 @@ pub const unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
 #[inline]
 #[must_use]
 #[stable(feature = "str_mut_extras", since = "1.20.0")]
-pub unsafe fn from_utf8_unchecked_mut(v: &mut [u8]) -> &mut str {
+#[rustc_const_unstable(feature = "const_str_from_utf8_unchecked_mut", issue = "91005")]
+pub const unsafe fn from_utf8_unchecked_mut(v: &mut [u8]) -> &mut str {
     // SAFETY: the caller must guarantee that the bytes `v`
     // are valid UTF-8, thus the cast to `*mut str` is safe.
     // Also, the pointer dereference is safe because that pointer

library/core/src/str/error.rs

@@ -72,9 +72,10 @@ impl Utf8Error {
     /// assert_eq!(1, error.valid_up_to());
     /// ```
     #[stable(feature = "utf8_error", since = "1.5.0")]
+    #[rustc_const_unstable(feature = "const_str_from_utf8", issue = "91006")]
     #[must_use]
     #[inline]
-    pub fn valid_up_to(&self) -> usize {
+    pub const fn valid_up_to(&self) -> usize {
         self.valid_up_to
     }
 
@@ -94,10 +95,15 @@ impl Utf8Error {
     ///
     /// [U+FFFD]: ../../std/char/constant.REPLACEMENT_CHARACTER.html
     #[stable(feature = "utf8_error_error_len", since = "1.20.0")]
+    #[rustc_const_unstable(feature = "const_str_from_utf8", issue = "91006")]
     #[must_use]
     #[inline]
-    pub fn error_len(&self) -> Option<usize> {
-        self.error_len.map(|len| len as usize)
+    pub const fn error_len(&self) -> Option<usize> {
+        // This should become `map` again, once it's `const`
+        match self.error_len {
+            Some(len) => Some(len as usize),
+            None => None,
+        }
     }
 }