Auto merge of #132099 - matthiaskrgr:rollup-myi94r8, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #129248 (Taking a raw ref (`&raw (const|mut)`) of a deref of pointer (`*ptr`) is always safe)
 - #131906 (rustdoc: adjust spacing and typography in header)
 - #132084 (Consider param-env candidates even if they have errors)
 - #132096 (Replace an FTP link in comments with an equivalent HTTPS link)
 - #132098 (rustc_feature::Features: explain what that 'Option<Symbol>' is about)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_data_structures/src/graph/dominators/mod.rs

@@ -2,7 +2,7 @@
 //!
 //! Algorithm based on Loukas Georgiadis,
 //! "Linear-Time Algorithms for Dominators and Related Problems",
-//! <ftp://ftp.cs.princeton.edu/techreports/2005/737.pdf>
+//! <https://www.cs.princeton.edu/techreports/2005/737.pdf>
 //!
 //! Additionally useful is the original Lengauer-Tarjan paper on this subject,
 //! "A Fast Algorithm for Finding Dominators in a Flowgraph"

compiler/rustc_feature/src/unstable.rs

@@ -44,6 +44,8 @@ pub struct Features {
 }
 
 impl Features {
+    /// `since` should be set for stable features that are nevertheless enabled with a `#[feature]`
+    /// attribute, indicating since when they are stable.
     pub fn set_enabled_lang_feature(&mut self, name: Symbol, span: Span, since: Option<Symbol>) {
         self.enabled_lang_features.push((name, span, since));
         self.enabled_features.insert(name);
@@ -54,6 +56,10 @@ impl Features {
         self.enabled_features.insert(name);
     }
 
+    /// Returns a list of triples with:
+    /// - feature gate name
+    /// - the span of the `#[feature]` attribute
+    /// - (for already stable features) the version since which it is stable
     pub fn enabled_lang_features(&self) -> &Vec<(Symbol, Span, Option<Symbol>)> {
         &self.enabled_lang_features
     }

compiler/rustc_lint/src/builtin.rs

@@ -2657,8 +2657,8 @@ declare_lint! {
     ///
     /// ### Explanation
     ///
-    /// Dereferencing a null pointer causes [undefined behavior] even as a place expression,
-    /// like `&*(0 as *const i32)` or `addr_of!(*(0 as *const i32))`.
+    /// Dereferencing a null pointer causes [undefined behavior] if it is accessed
+    /// (loaded from or stored to).
     ///
     /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
     pub DEREF_NULLPTR,
@@ -2673,14 +2673,14 @@ impl<'tcx> LateLintPass<'tcx> for DerefNullPtr {
         /// test if expression is a null ptr
         fn is_null_ptr(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool {
             match &expr.kind {
-                rustc_hir::ExprKind::Cast(expr, ty) => {
-                    if let rustc_hir::TyKind::Ptr(_) = ty.kind {
+                hir::ExprKind::Cast(expr, ty) => {
+                    if let hir::TyKind::Ptr(_) = ty.kind {
                         return is_zero(expr) || is_null_ptr(cx, expr);
                     }
                 }
                 // check for call to `core::ptr::null` or `core::ptr::null_mut`
-                rustc_hir::ExprKind::Call(path, _) => {
-                    if let rustc_hir::ExprKind::Path(ref qpath) = path.kind {
+                hir::ExprKind::Call(path, _) => {
+                    if let hir::ExprKind::Path(ref qpath) = path.kind {
                         if let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() {
                             return matches!(
                                 cx.tcx.get_diagnostic_name(def_id),
@@ -2697,7 +2697,7 @@ impl<'tcx> LateLintPass<'tcx> for DerefNullPtr {
         /// test if expression is the literal `0`
         fn is_zero(expr: &hir::Expr<'_>) -> bool {
             match &expr.kind {
-                rustc_hir::ExprKind::Lit(lit) => {
+                hir::ExprKind::Lit(lit) => {
                     if let LitKind::Int(a, _) = lit.node {
                         return a == 0;
                     }
@@ -2707,8 +2707,16 @@ impl<'tcx> LateLintPass<'tcx> for DerefNullPtr {
             false
         }
 
-        if let rustc_hir::ExprKind::Unary(rustc_hir::UnOp::Deref, expr_deref) = expr.kind {
-            if is_null_ptr(cx, expr_deref) {
+        if let hir::ExprKind::Unary(hir::UnOp::Deref, expr_deref) = expr.kind
+            && is_null_ptr(cx, expr_deref)
+        {
+            if let hir::Node::Expr(hir::Expr {
+                kind: hir::ExprKind::AddrOf(hir::BorrowKind::Raw, ..),
+                ..
+            }) = cx.tcx.parent_hir_node(expr.hir_id)
+            {
+                // `&raw *NULL` is ok.
+            } else {
                 cx.emit_span_lint(DEREF_NULLPTR, expr.span, BuiltinDerefNullptr {
                     label: expr.span,
                 });

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -509,20 +509,12 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             }
             ExprKind::RawBorrow { arg, .. } => {
                 if let ExprKind::Scope { value: arg, .. } = self.thir[arg].kind
-                // THIR desugars UNSAFE_STATIC into *UNSAFE_STATIC_REF, where
-                // UNSAFE_STATIC_REF holds the addr of the UNSAFE_STATIC, so: take two steps
                     && let ExprKind::Deref { arg } = self.thir[arg].kind
-                    // FIXME(workingjubiee): we lack a clear reason to reject ThreadLocalRef here,
-                    // but we also have no conclusive reason to allow it either!
-                    && let ExprKind::StaticRef { .. } = self.thir[arg].kind
                 {
-                    // A raw ref to a place expr, even an "unsafe static", is okay!
-                    // We short-circuit to not recursively traverse this expression.
+                    // Taking a raw ref to a deref place expr is always safe.
+                    // Make sure the expression we're deref'ing is safe, though.
+                    visit::walk_expr(self, &self.thir[arg]);
                     return;
-                    // note: const_mut_refs enables this code, and it currently remains unsafe:
-                    // static mut BYTE: u8 = 0;
-                    // static mut BYTE_PTR: *mut u8 = unsafe { addr_of_mut!(BYTE) };
-                    // static mut DEREF_BYTE_PTR: *mut u8 = unsafe { addr_of_mut!(*BYTE_PTR) };
                 }
             }
             ExprKind::Deref { arg } => {

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -244,7 +244,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             .param_env
             .caller_bounds()
             .iter()
-            .filter(|p| !p.references_error())
             .filter_map(|p| p.as_trait_clause())
             // Micro-optimization: filter out predicates relating to different traits.
             .filter(|p| p.def_id() == stack.obligation.predicate.def_id())

src/librustdoc/html/render/mod.rs

@@ -2010,9 +2010,9 @@ fn render_rightside(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, render
     );
     if let Some(link) = src_href {
         if has_stability {
-            write!(rightside, " · <a class=\"src\" href=\"{link}\">source</a>")
+            write!(rightside, " · <a class=\"src\" href=\"{link}\">Source</a>")
         } else {
-            write!(rightside, "<a class=\"src rightside\" href=\"{link}\">source</a>")
+            write!(rightside, "<a class=\"src rightside\" href=\"{link}\">Source</a>")
         }
     }
     if has_stability && has_src_ref {

src/librustdoc/html/static/css/rustdoc.css

@@ -185,7 +185,7 @@ h1, h2, h3, h4 {
 	grid-template-columns: minmax(105px, 1fr) minmax(0, max-content);
 	grid-template-rows: minmax(25px, min-content) min-content min-content;
 	padding-bottom: 6px;
-	margin-bottom: 11px;
+	margin-bottom: 15px;
 }
 .rustdoc-breadcrumbs {
 	grid-area: main-heading-breadcrumbs;
@@ -1004,6 +1004,7 @@ nav.sub {
 	display: flex;
 	height: 34px;
 	flex-grow: 1;
+	margin-bottom: 4px;
 }
 .src nav.sub {
 	margin: 0 0 -10px 0;
@@ -2253,7 +2254,12 @@ in src-script.js and main.js
 
 	/* We don't display this button on mobile devices. */
 	#copy-path {
-		display: none;
+		/* display: none; avoided as a layout hack.
+			When there's one line, we get an effective line-height of 34px,
+			because that's how big the image is, but if the header wraps,
+			they're packed more tightly than that. */
+		width: 0;
+		visibility: hidden;
 	}
 
 	/* Text label takes up too much space at this size. */

src/librustdoc/html/templates/print_item.html

@@ -26,7 +26,7 @@ <h1>
         {% match src_href %}
             {% when Some with (href) %}
                 {% if !stability_since_raw.is_empty() +%} · {%+ endif %}
-                <a class="src" href="{{href|safe}}">source</a> {#+ #}
+                <a class="src" href="{{href|safe}}">Source</a> {#+ #}
             {% else %}
         {% endmatch %}
     </span> {# #}

tests/rustdoc-gui/item-info.goml

@@ -20,7 +20,7 @@ store-position: (
     {"x": second_line_x, "y": second_line_y},
 )
 assert: |first_line_x| != |second_line_x| && |first_line_x| == 516 && |second_line_x| == 272
-assert: |first_line_y| != |second_line_y| && |first_line_y| == 714 && |second_line_y| == 737
+assert: |first_line_y| != |second_line_y| && |first_line_y| == 718 && |second_line_y| == 741
 
 // Now we ensure that they're not rendered on the same line.
 set-window-size: (1100, 800)

tests/rustdoc-gui/scrape-examples-layout.goml

@@ -80,8 +80,8 @@ click: ".scraped-example .button-holder .expand"
 store-value: (offset_y, 4)
 
 // First with desktop
-assert-position: (".scraped-example", {"y": 252})
-assert-position: (".scraped-example .prev", {"y": 252 + |offset_y|})
+assert-position: (".scraped-example", {"y": 256})
+assert-position: (".scraped-example .prev", {"y": 256 + |offset_y|})
 
 // Gradient background should be at the top of the code block.
 assert-css: (".scraped-example .example-wrap::before", {"top": "0px"})
@@ -90,8 +90,8 @@ assert-css: (".scraped-example .example-wrap::after", {"bottom": "0px"})
 // Then with mobile
 set-window-size: (600, 600)
 store-size: (".scraped-example .scraped-example-title", {"height": title_height})
-assert-position: (".scraped-example", {"y": 287})
-assert-position: (".scraped-example .prev", {"y": 287 + |offset_y| + |title_height|})
+assert-position: (".scraped-example", {"y": 291})
+assert-position: (".scraped-example .prev", {"y": 291 + |offset_y| + |title_height|})
 
 define-function: (
     "check_title_and_code_position",

tests/rustdoc-gui/sidebar-source-code-display.goml

@@ -141,7 +141,7 @@ click: "#sidebar-button"
 wait-for-css: (".src .sidebar > *", {"visibility": "hidden"})
 // We scroll to line 117 to change the scroll position.
 scroll-to: '//*[@id="117"]'
-store-value: (y_offset, "2570")
+store-value: (y_offset, "2578")
 assert-window-property: {"pageYOffset": |y_offset|}
 // Expanding the sidebar...
 click: "#sidebar-button"

tests/rustdoc-gui/source-anchor-scroll.goml

@@ -8,13 +8,13 @@ set-window-size: (600, 800)
 assert-property: ("html", {"scrollTop": "0"})
 
 click: '//a[text() = "barbar" and @href="#5-7"]'
-assert-property: ("html", {"scrollTop": "200"})
+assert-property: ("html", {"scrollTop": "208"})
 click: '//a[text() = "bar" and @href="#28-36"]'
-assert-property: ("html", {"scrollTop": "231"})
+assert-property: ("html", {"scrollTop": "239"})
 click: '//a[normalize-space() = "sub_fn" and @href="#2-4"]'
-assert-property: ("html", {"scrollTop": "128"})
+assert-property: ("html", {"scrollTop": "136"})
 
 // We now check that clicking on lines doesn't change the scroll
 // Extra information: the "sub_fn" function header is on line 1.
 click: '//*[@id="6"]'
-assert-property: ("html", {"scrollTop": "128"})
+assert-property: ("html", {"scrollTop": "136"})

tests/rustdoc-gui/source-code-page.goml

@@ -89,7 +89,7 @@ assert-css: (".src-line-numbers", {"text-align": "right"})
 // do anything (and certainly not add a `#NaN` to the URL!).
 go-to: "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html"
 // We use this assert-position to know where we will click.
-assert-position: ("//*[@id='1']", {"x": 88, "y": 163})
+assert-position: ("//*[@id='1']", {"x": 88, "y": 171})
 // We click on the left of the "1" anchor but still in the "src-line-number" `<pre>`.
 click: (163, 77)
 assert-document-property: ({"URL": "/lib.rs.html"}, ENDS_WITH)
@@ -165,15 +165,15 @@ assert-css: ("nav.sub", {"flex-direction": "row"})
 // offsetTop[nav.sub form] = offsetTop[#main-content] - offsetHeight[nav.sub form] - offsetTop[nav.sub form]
 assert-position: ("nav.sub form", {"y": 15})
 assert-property: ("nav.sub form", {"offsetHeight": 34})
-assert-position: ("h1", {"y": 64})
+assert-position: ("h1", {"y": 68})
 // 15 = 64 - 34 - 15
 
 // Now do the same check on moderately-sized, tablet mobile.
 set-window-size: (700, 700)
 assert-css: ("nav.sub", {"flex-direction": "row"})
 assert-position: ("nav.sub form", {"y": 8})
 assert-property: ("nav.sub form", {"offsetHeight": 34})
-assert-position: ("h1", {"y": 50})
+assert-position: ("h1", {"y": 54})
 // 8 = 50 - 34 - 8
 
 // Check the sidebar directory entries have a marker and spacing (tablet).

tests/rustdoc/anchors.no_const_anchor.html

@@ -1 +1 @@
-<section id="associatedconstant.YOLO" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#16">source</a><h4 class="code-header">const <a href="#associatedconstant.YOLO" class="constant">YOLO</a>: <a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a></h4></section>
+<section id="associatedconstant.YOLO" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#16">Source</a><h4 class="code-header">const <a href="#associatedconstant.YOLO" class="constant">YOLO</a>: <a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a></h4></section>

tests/rustdoc/anchors.no_const_anchor2.html

@@ -1 +1 @@
-<section id="associatedconstant.X" class="associatedconstant"><a class="src rightside" href="../src/foo/anchors.rs.html#42">source</a><h4 class="code-header">pub const <a href="#associatedconstant.X" class="constant">X</a>: <a class="primitive" href="{{channel}}/std/primitive.i32.html">i32</a> = 0i32</h4></section>
+<section id="associatedconstant.X" class="associatedconstant"><a class="src rightside" href="../src/foo/anchors.rs.html#42">Source</a><h4 class="code-header">pub const <a href="#associatedconstant.X" class="constant">X</a>: <a class="primitive" href="{{channel}}/std/primitive.i32.html">i32</a> = 0i32</h4></section>

tests/rustdoc/anchors.no_method_anchor.html

@@ -1 +1 @@
-<section id="method.new" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#48">source</a><h4 class="code-header">pub fn <a href="#method.new" class="fn">new</a>() -&gt; Self</h4></section>
+<section id="method.new" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#48">Source</a><h4 class="code-header">pub fn <a href="#method.new" class="fn">new</a>() -&gt; Self</h4></section>

tests/rustdoc/anchors.no_trait_method_anchor.html

@@ -1 +1 @@
-<section id="method.bar" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#23">source</a><h4 class="code-header">fn <a href="#method.bar" class="fn">bar</a>()</h4></section>
+<section id="method.bar" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#23">Source</a><h4 class="code-header">fn <a href="#method.bar" class="fn">bar</a>()</h4></section>

tests/rustdoc/anchors.no_tymethod_anchor.html

@@ -1 +1 @@
-<section id="tymethod.foo" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#20">source</a><h4 class="code-header">fn <a href="#tymethod.foo" class="fn">foo</a>()</h4></section>
+<section id="tymethod.foo" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#20">Source</a><h4 class="code-header">fn <a href="#tymethod.foo" class="fn">foo</a>()</h4></section>

tests/rustdoc/anchors.no_type_anchor.html

@@ -1 +1 @@
-<section id="associatedtype.T" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#13">source</a><h4 class="code-header">type <a href="#associatedtype.T" class="associatedtype">T</a></h4></section>
+<section id="associatedtype.T" class="method"><a class="src rightside" href="../src/foo/anchors.rs.html#13">Source</a><h4 class="code-header">type <a href="#associatedtype.T" class="associatedtype">T</a></h4></section>

tests/rustdoc/anchors.no_type_anchor2.html

@@ -1 +1 @@
-<section id="associatedtype.Y" class="associatedtype"><a class="src rightside" href="../src/foo/anchors.rs.html#45">source</a><h4 class="code-header">pub type <a href="#associatedtype.Y" class="associatedtype">Y</a> = <a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a></h4></section>
+<section id="associatedtype.Y" class="associatedtype"><a class="src rightside" href="../src/foo/anchors.rs.html#45">Source</a><h4 class="code-header">pub type <a href="#associatedtype.Y" class="associatedtype">Y</a> = <a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a></h4></section>

tests/rustdoc/assoc-type-source-link.rs

@@ -8,7 +8,7 @@
 pub struct Bar;
 
 impl Bar {
-    //@ has - '//*[@id="implementations-list"]//*[@id="associatedtype.Y"]/a' 'source'
+    //@ has - '//*[@id="implementations-list"]//*[@id="associatedtype.Y"]/a' 'Source'
     //@ has - '//*[@id="implementations-list"]//*[@id="associatedtype.Y"]/a/@href' \
     // '../src/foo/assoc-type-source-link.rs.html#14'
     pub type Y = u8;
@@ -19,7 +19,7 @@ pub trait Foo {
 }
 
 impl Foo for Bar {
-    //@ has - '//*[@id="trait-implementations-list"]//*[@id="associatedtype.Z"]/a' 'source'
+    //@ has - '//*[@id="trait-implementations-list"]//*[@id="associatedtype.Z"]/a' 'Source'
     //@ has - '//*[@id="trait-implementations-list"]//*[@id="associatedtype.Z"]/a/@href' \
     // '../src/foo/assoc-type-source-link.rs.html#25'
     type Z = u8;