Auto merge of #151837 - JonathanBrouwer:rollup-qIYP0mi, r=JonathanBrouwer

Rollup of 4 pull requests

Successful merges:

 - #151808 (Document a safety condition for `TypedArena::alloc_raw_slice`)
 - #151811 (Fix false positive in unused_parens caused by break)
 - #151817 (Fix missing syntax context in lifetime hygiene debug output)
 - #151836 (Fix flakyness issue with `tests/rustdoc-gui/globals.goml` test)

Author: bors

compiler/rustc_arena/src/lib.rs

@@ -172,8 +172,22 @@ impl<T> TypedArena<T> {
         available_bytes >= additional_bytes
     }
 
+    /// Allocates storage for `len >= 1` values in this arena, and returns a
+    /// raw pointer to the first value's storage.
+    ///
+    /// # Safety
+    ///
+    /// Caller must initialize each of the `len` slots to a droppable value
+    /// before the arena is dropped.
+    ///
+    /// In practice, this typically means that the caller must be able to
+    /// raw-copy `len` already-initialized values into the slice without any
+    /// possibility of panicking.
+    ///
+    /// FIXME(Zalathar): This is *very* fragile; perhaps we need a different
+    /// approach to arena-allocating slices of droppable values.
     #[inline]
-    fn alloc_raw_slice(&self, len: usize) -> *mut T {
+    unsafe fn alloc_raw_slice(&self, len: usize) -> *mut T {
         assert!(size_of::<T>() != 0);
         assert!(len != 0);
 
@@ -208,7 +222,7 @@ impl<T> TypedArena<T> {
         &self,
         iter: impl IntoIterator<Item = Result<T, E>>,
     ) -> Result<&mut [T], E> {
-        // Despite the similarlty with `DroplessArena`, we cannot reuse their fast case. The reason
+        // Despite the similarity with `DroplessArena`, we cannot reuse their fast case. The reason
         // is subtle: these arenas are reentrant. In other words, `iter` may very well be holding a
         // reference to `self` and adding elements to the arena during iteration.
         //
@@ -229,9 +243,15 @@ impl<T> TypedArena<T> {
         }
         // Move the content to the arena by copying and then forgetting it.
         let len = vec.len();
-        let start_ptr = self.alloc_raw_slice(len);
+
+        // SAFETY: After allocating raw storage for exactly `len` values, we
+        // must fully initialize the storage without panicking, and we must
+        // also prevent the stale values in the vec from being dropped.
         Ok(unsafe {
+            let start_ptr = self.alloc_raw_slice(len);
+            // Initialize the newly-allocated storage without panicking.
             vec.as_ptr().copy_to_nonoverlapping(start_ptr, len);
+            // Prevent the stale values in the vec from being dropped.
             vec.set_len(0);
             slice::from_raw_parts_mut(start_ptr, len)
         })
@@ -584,7 +604,7 @@ impl DroplessArena {
         &self,
         iter: impl IntoIterator<Item = Result<T, E>>,
     ) -> Result<&mut [T], E> {
-        // Despite the similarlty with `alloc_from_iter`, we cannot reuse their fast case, as we
+        // Despite the similarity with `alloc_from_iter`, we cannot reuse their fast case, as we
         // cannot know the minimum length of the iterator in this case.
         assert!(size_of::<T>() != 0);
 

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -1961,7 +1961,8 @@ impl<'a> State<'a> {
     }
 
     fn print_lifetime(&mut self, lifetime: ast::Lifetime) {
-        self.print_name(lifetime.ident.name)
+        self.word(lifetime.ident.name.to_string());
+        self.ann_post(lifetime.ident)
     }
 
     fn print_lifetime_bounds(&mut self, bounds: &ast::GenericBounds) {

compiler/rustc_lint/src/unused.rs

@@ -805,7 +805,10 @@ trait UnusedDelimLint {
 
                 ExprKind::Break(_label, None) => return false,
                 ExprKind::Break(_label, Some(break_expr)) => {
-                    return matches!(break_expr.kind, ExprKind::Block(..));
+                    // `if (break 'label i) { ... }` removing parens would make `i { ... }`
+                    // be parsed as a struct literal, so keep parentheses if the break value
+                    // ends with a path (which could be mistaken for a struct name).
+                    return matches!(break_expr.kind, ExprKind::Block(..) | ExprKind::Path(..));
                 }
 
                 ExprKind::Range(_lhs, Some(rhs), _limits) => {

tests/rustdoc-gui/globals.goml

@@ -11,7 +11,7 @@ assert-window-property-false: {"searchIndex": null}
 // Form input
 go-to: "file://" + |DOC_PATH| + "/test_docs/index.html"
 call-function: ("perform-search", {"query": "Foo"})
-assert-window-property-false: {"searchIndex": null}
+wait-for-window-property-false: {"searchIndex": null}
 
 // source sidebar
 go-to: "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html"

tests/ui/hygiene/unpretty-debug-lifetimes.rs

@@ -0,0 +1,18 @@
+//@ check-pass
+//@ compile-flags: -Zunpretty=expanded,hygiene
+
+// Regression test for lifetime hygiene annotations in -Zunpretty=expanded,hygiene
+// Previously, lifetimes were missing the #N syntax context suffix.
+
+// Don't break whenever Symbol numbering changes
+//@ normalize-stdout: "\d+#" -> "0#"
+
+#![feature(decl_macro)]
+#![feature(no_core)]
+#![no_core]
+
+macro lifetime_hygiene($f:ident<$a:lifetime>) {
+    fn $f<$a, 'a>() {}
+}
+
+lifetime_hygiene!(f<'a>);

tests/ui/hygiene/unpretty-debug-lifetimes.stdout

@@ -0,0 +1,31 @@
+//@ check-pass
+//@ compile-flags: -Zunpretty=expanded,hygiene
+
+// Regression test for lifetime hygiene annotations in -Zunpretty=expanded,hygiene
+// Previously, lifetimes were missing the #N syntax context suffix.
+
+// Don't break whenever Symbol numbering changes
+//@ normalize-stdout: "\d+#" -> "0#"
+
+#![feature /* 0#0 */(decl_macro)]
+#![feature /* 0#0 */(no_core)]
+#![no_core /* 0#0 */]
+
+macro lifetime_hygiene
+    /*
+    0#0
+    */ {
+    ($f:ident<$a:lifetime>) => { fn $f<$a, 'a>() {} }
+}
+fn f /* 0#0 */<'a /* 0#0 */, 'a /* 0#1 */>() {}
+
+
+/*
+Expansions:
+crate0::{{expn0}}: parent: crate0::{{expn0}}, call_site_ctxt: #0, def_site_ctxt: #0, kind: Root
+crate0::{{expn1}}: parent: crate0::{{expn0}}, call_site_ctxt: #0, def_site_ctxt: #0, kind: Macro(Bang, "lifetime_hygiene")
+
+SyntaxContexts:
+#0: parent: #0, outer_mark: (crate0::{{expn0}}, Opaque)
+#1: parent: #0, outer_mark: (crate0::{{expn1}}, Opaque)
+*/

tests/ui/lint/unused-parens-labeled-break-issue-143256.rs

@@ -0,0 +1,25 @@
+//@ check-pass
+// testcase for https://github.com/rust-lang/rust/issues/143256
+
+#![deny(unused_parens)]
+#![allow(unreachable_code, unused_variables, dead_code)]
+
+fn foo() {
+    let _x = || 'outer: loop {
+        let inner = 'inner: loop {
+            let i = Default::default();
+            // the parentheses here are necessary
+            if (break 'outer i) {
+                loop {
+                    break 'inner 5i8;
+                }
+            } else if true {
+                break 'inner 6;
+            }
+            break 7;
+        };
+        break inner < 8;
+    };
+}
+
+fn main() {}

typos.toml

@@ -46,6 +46,7 @@ unstalled = "unstalled" # short for un-stalled
 #
 # tidy-alphabetical-start
 definitinon = "definition"
+similarlty = "similarity"
 # tidy-alphabetical-end
 
 [default.extend-identifiers]