Auto merge of #93498 - matthiaskrgr:rollup-k5shwrc, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #90277 (Improve terminology around "after typeck")
 - #92918 (Allow eliding GATs in expression position)
 - #93039 (Don't suggest inaccessible fields)
 - #93155 (Switch pretty printer to block-based indentation)
 - #93214 (Respect doc(hidden) when suggesting available fields)
 - #93347 (Make `char::DecodeUtf16::size_hist` more precise)
 - #93392 (Clarify documentation on char::MAX)
 - #93444 (Fix some CSS warnings and errors from VS Code)

Failed merges:

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

compiler/rustc_ast_pretty/src/pp.rs

@@ -146,6 +146,22 @@ pub enum Breaks {
     Inconsistent,
 }
 
+#[derive(Clone, Copy)]
+enum IndentStyle {
+    /// Vertically aligned under whatever column this block begins at.
+    ///
+    ///     fn demo(arg1: usize,
+    ///             arg2: usize);
+    Visual,
+    /// Indented relative to the indentation level of the previous line.
+    ///
+    ///     fn demo(
+    ///         arg1: usize,
+    ///         arg2: usize,
+    ///     );
+    Block { offset: isize },
+}
+
 #[derive(Clone, Copy)]
 pub struct BreakToken {
     offset: isize,
@@ -154,7 +170,7 @@ pub struct BreakToken {
 
 #[derive(Clone, Copy)]
 pub struct BeginToken {
-    offset: isize,
+    indent: IndentStyle,
     breaks: Breaks,
 }
 
@@ -178,7 +194,7 @@ impl Token {
 #[derive(Copy, Clone)]
 enum PrintFrame {
     Fits,
-    Broken { offset: isize, breaks: Breaks },
+    Broken { indent: usize, breaks: Breaks },
 }
 
 const SIZE_INFINITY: isize = 0xffff;
@@ -204,6 +220,8 @@ pub struct Printer {
     scan_stack: VecDeque<usize>,
     /// Stack of blocks-in-progress being flushed by print
     print_stack: Vec<PrintFrame>,
+    /// Level of indentation of current line
+    indent: usize,
     /// Buffered indentation to avoid writing trailing whitespace
     pending_indentation: isize,
     /// The token most recently popped from the left boundary of the
@@ -229,6 +247,7 @@ impl Printer {
             right_total: 0,
             scan_stack: VecDeque::new(),
             print_stack: Vec::new(),
+            indent: 0,
             pending_indentation: 0,
             last_printed: None,
         }
@@ -368,38 +387,41 @@ impl Printer {
         *self
             .print_stack
             .last()
-            .unwrap_or(&PrintFrame::Broken { offset: 0, breaks: Breaks::Inconsistent })
+            .unwrap_or(&PrintFrame::Broken { indent: 0, breaks: Breaks::Inconsistent })
     }
 
     fn print_begin(&mut self, token: BeginToken, size: isize) {
         if size > self.space {
-            let col = self.margin - self.space + token.offset;
-            self.print_stack.push(PrintFrame::Broken { offset: col, breaks: token.breaks });
+            self.print_stack.push(PrintFrame::Broken { indent: self.indent, breaks: token.breaks });
+            self.indent = match token.indent {
+                IndentStyle::Block { offset } => (self.indent as isize + offset) as usize,
+                IndentStyle::Visual => (self.margin - self.space) as usize,
+            };
         } else {
             self.print_stack.push(PrintFrame::Fits);
         }
     }
 
     fn print_end(&mut self) {
-        self.print_stack.pop().unwrap();
+        if let PrintFrame::Broken { indent, .. } = self.print_stack.pop().unwrap() {
+            self.indent = indent;
+        }
     }
 
     fn print_break(&mut self, token: BreakToken, size: isize) {
-        let break_offset =
-            match self.get_top() {
-                PrintFrame::Fits => None,
-                PrintFrame::Broken { offset, breaks: Breaks::Consistent } => Some(offset),
-                PrintFrame::Broken { offset, breaks: Breaks::Inconsistent } => {
-                    if size > self.space { Some(offset) } else { None }
-                }
-            };
-        if let Some(offset) = break_offset {
-            self.out.push('\n');
-            self.pending_indentation = offset + token.offset;
-            self.space = self.margin - (offset + token.offset);
-        } else {
+        let fits = match self.get_top() {
+            PrintFrame::Fits => true,
+            PrintFrame::Broken { breaks: Breaks::Consistent, .. } => false,
+            PrintFrame::Broken { breaks: Breaks::Inconsistent, .. } => size <= self.space,
+        };
+        if fits {
             self.pending_indentation += token.blank_space;
             self.space -= token.blank_space;
+        } else {
+            self.out.push('\n');
+            let indent = self.indent as isize + token.offset;
+            self.pending_indentation = indent;
+            self.space = self.margin - indent;
         }
     }
 
@@ -422,7 +444,10 @@ impl Printer {
 
     /// "raw box"
     pub fn rbox(&mut self, indent: usize, breaks: Breaks) {
-        self.scan_begin(BeginToken { offset: indent as isize, breaks })
+        self.scan_begin(BeginToken {
+            indent: IndentStyle::Block { offset: indent as isize },
+            breaks,
+        })
     }
 
     /// Inconsistent breaking box
@@ -435,6 +460,10 @@ impl Printer {
         self.rbox(indent, Breaks::Consistent)
     }
 
+    pub fn visual_align(&mut self) {
+        self.scan_begin(BeginToken { indent: IndentStyle::Visual, breaks: Breaks::Consistent });
+    }
+
     pub fn break_offset(&mut self, n: usize, off: isize) {
         self.scan_break(BreakToken { offset: off, blank_space: n as isize })
     }

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -315,7 +315,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
                     self.word(cmnt.lines[0].clone());
                     self.hardbreak()
                 } else {
-                    self.ibox(0);
+                    self.visual_align();
                     for line in &cmnt.lines {
                         if !line.is_empty() {
                             self.word(line.clone());
@@ -655,7 +655,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
         // Outer-box is consistent.
         self.cbox(INDENT_UNIT);
         // Head-box is inconsistent.
-        self.ibox(w.len() + 1);
+        self.ibox(0);
         // Keyword that starts the head.
         if !w.is_empty() {
             self.word_nbsp(w);

compiler/rustc_ast_pretty/src/pprust/state/expr.rs

@@ -320,7 +320,9 @@ impl<'a> State<'a> {
                     self.print_ident(label.ident);
                     self.word_space(":");
                 }
-                self.head("while");
+                self.cbox(0);
+                self.ibox(0);
+                self.word_nbsp("while");
                 self.print_expr_as_cond(test);
                 self.space();
                 self.print_block_with_attrs(blk, attrs);
@@ -330,7 +332,9 @@ impl<'a> State<'a> {
                     self.print_ident(label.ident);
                     self.word_space(":");
                 }
-                self.head("for");
+                self.cbox(0);
+                self.ibox(0);
+                self.word_nbsp("for");
                 self.print_pat(pat);
                 self.space();
                 self.word_space("in");
@@ -343,12 +347,14 @@ impl<'a> State<'a> {
                     self.print_ident(label.ident);
                     self.word_space(":");
                 }
-                self.head("loop");
+                self.cbox(0);
+                self.ibox(0);
+                self.word_nbsp("loop");
                 self.print_block_with_attrs(blk, attrs);
             }
             ast::ExprKind::Match(ref expr, ref arms) => {
-                self.cbox(INDENT_UNIT);
-                self.ibox(INDENT_UNIT);
+                self.cbox(0);
+                self.ibox(0);
                 self.word_nbsp("match");
                 self.print_expr_as_cond(expr);
                 self.space();
@@ -388,7 +394,7 @@ impl<'a> State<'a> {
                     self.word_space(":");
                 }
                 // containing cbox, will be closed by print-block at }
-                self.cbox(INDENT_UNIT);
+                self.cbox(0);
                 // head-box, will be closed by print-block after {
                 self.ibox(0);
                 self.print_block_with_attrs(blk, attrs);
@@ -397,7 +403,7 @@ impl<'a> State<'a> {
                 self.word_nbsp("async");
                 self.print_capture_clause(capture_clause);
                 // cbox/ibox in analogy to the `ExprKind::Block` arm above
-                self.cbox(INDENT_UNIT);
+                self.cbox(0);
                 self.ibox(0);
                 self.print_block_with_attrs(blk, attrs);
             }
@@ -500,7 +506,9 @@ impl<'a> State<'a> {
                 self.word("?")
             }
             ast::ExprKind::TryBlock(ref blk) => {
-                self.head("try");
+                self.cbox(0);
+                self.ibox(0);
+                self.word_nbsp("try");
                 self.print_block_with_attrs(blk, attrs)
             }
             ast::ExprKind::Err => {

compiler/rustc_ast_pretty/src/pprust/state/item.rs

@@ -1,5 +1,5 @@
 use crate::pp::Breaks::Inconsistent;
-use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
+use crate::pprust::state::{AnnNode, PrintState, State};
 
 use rustc_ast as ast;
 use rustc_ast::GenericBound;
@@ -377,7 +377,7 @@ impl<'a> State<'a> {
             self.space_if_not_bol();
             self.maybe_print_comment(v.span.lo());
             self.print_outer_attributes(&v.attrs);
-            self.ibox(INDENT_UNIT);
+            self.ibox(0);
             self.print_variant(v);
             self.word(",");
             self.end();

compiler/rustc_infer/src/infer/mod.rs

@@ -195,7 +195,7 @@ pub struct InferCtxtInner<'tcx> {
     // Opaque types found in explicit return types and their
     // associated fresh inference variable. Writeback resolves these
     // variables to get the concrete type, which can be used to
-    // 'de-opaque' OpaqueTypeDecl, after typeck is done with all functions.
+    // 'de-opaque' OpaqueTypeDecl outside of type inference.
     pub opaque_types: OpaqueTypeMap<'tcx>,
 
     /// A map from inference variables created from opaque

compiler/rustc_lint/src/context.rs

@@ -524,7 +524,7 @@ impl LintStore {
     }
 }
 
-/// Context for lint checking after type checking.
+/// Context for lint checking outside of type inference.
 pub struct LateContext<'tcx> {
     /// Type context we're checking in.
     pub tcx: TyCtxt<'tcx>,

compiler/rustc_middle/src/mir/mod.rs

@@ -894,7 +894,7 @@ pub struct LocalDecl<'tcx> {
     /// across a suspension point against the type components of the generator
     /// which type checking knows are live across a suspension point. We need to
     /// flag drop flags to avoid triggering this check as they are introduced
-    /// after typeck.
+    /// outside of type inference.
     ///
     /// This should be sound because the drop flags are fully algebraic, and
     /// therefore don't affect the auto-trait or outlives properties of the

compiler/rustc_middle/src/ty/context.rs

@@ -220,7 +220,7 @@ pub struct CommonLifetimes<'tcx> {
     /// `ReStatic`
     pub re_static: Region<'tcx>,
 
-    /// Erased region, used after type-checking
+    /// Erased region, used outside of type inference.
     pub re_erased: Region<'tcx>,
 }
 
@@ -360,7 +360,7 @@ pub struct TypeckResults<'tcx> {
     field_indices: ItemLocalMap<usize>,
 
     /// Stores the types for various nodes in the AST. Note that this table
-    /// is not guaranteed to be populated until after typeck. See
+    /// is not guaranteed to be populated outside inference. See
     /// typeck::check::fn_ctxt for details.
     node_types: ItemLocalMap<Ty<'tcx>>,
 

compiler/rustc_middle/src/ty/normalize_erasing_regions.rs

@@ -34,8 +34,8 @@ impl<'tcx> TyCtxt<'tcx> {
     /// Erase the regions in `value` and then fully normalize all the
     /// types found within. The result will also have regions erased.
     ///
-    /// This is appropriate to use only after type-check: it assumes
-    /// that normalization will succeed, for example.
+    /// This should only be used outside of type inference. For example,
+    /// it assumes that normalization will succeed.
     pub fn normalize_erasing_regions<T>(self, param_env: ty::ParamEnv<'tcx>, value: T) -> T
     where
         T: TypeFoldable<'tcx>,

compiler/rustc_middle/src/ty/sty.rs

@@ -1464,11 +1464,11 @@ pub enum RegionKind {
     /// Static data that has an "infinite" lifetime. Top in the region lattice.
     ReStatic,
 
-    /// A region variable. Should not exist after typeck.
+    /// A region variable. Should not exist outside of type inference.
     ReVar(RegionVid),
 
     /// A placeholder region -- basically, the higher-ranked version of `ReFree`.
-    /// Should not exist after typeck.
+    /// Should not exist outside of type inference.
     RePlaceholder(ty::PlaceholderRegion),
 
     /// Empty lifetime is for data that is never accessed.  We tag the

compiler/rustc_save_analysis/src/lib.rs

@@ -984,7 +984,7 @@ pub fn process_crate<'l, 'tcx, H: SaveHandler>(
         tcx.dep_graph.with_ignore(|| {
             info!("Dumping crate {}", cratename);
 
-            // Privacy checking requires and is done after type checking; use a
+            // Privacy checking must be done outside of type inference; use a
             // fallback in case the access levels couldn't have been correctly computed.
             let access_levels = match tcx.sess.compile_status() {
                 Ok(..) => tcx.privacy_access_levels(()),

compiler/rustc_target/src/asm/mod.rs

@@ -444,7 +444,7 @@ impl InlineAsmRegClass {
     }
 
     /// Returns a suggested register class to use for this type. This is called
-    /// after type checking via `supported_types` fails to give a better error
+    /// when `supported_types` fails to give a better error
     /// message to the user.
     pub fn suggest_class(self, arch: InlineAsmArch, ty: InlineAsmType) -> Option<Self> {
         match self {

compiler/rustc_trait_selection/src/traits/codegen.rs

@@ -18,7 +18,6 @@ use rustc_middle::ty::{self, TyCtxt};
 /// that type check should guarantee to us that all nested
 /// obligations *could be* resolved if we wanted to.
 ///
-/// Assumes that this is run after the entire crate has been successfully type-checked.
 /// This also expects that `trait_ref` is fully normalized.
 pub fn codegen_fulfill_obligation<'tcx>(
     tcx: TyCtxt<'tcx>,
@@ -101,7 +100,7 @@ pub fn codegen_fulfill_obligation<'tcx>(
 /// Finishes processes any obligations that remain in the
 /// fulfillment context, and then returns the result with all type
 /// variables removed and regions erased. Because this is intended
-/// for use after type-check has completed, if any errors occur,
+/// for use outside of type inference, if any errors occur,
 /// it will panic. It is used during normalization and other cases
 /// where processing the obligations in `fulfill_cx` may cause
 /// type inference variables that appear in `result` to be
@@ -124,7 +123,10 @@ where
     if !errors.is_empty() {
         infcx.tcx.sess.delay_span_bug(
             rustc_span::DUMMY_SP,
-            &format!("Encountered errors `{:?}` resolving bounds after type-checking", errors),
+            &format!(
+                "Encountered errors `{:?}` resolving bounds outside of type inference",
+                errors
+            ),
         );
     }
 

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -291,7 +291,7 @@ pub fn normalize_param_env_or_error<'tcx>(
     //
     // In any case, in practice, typeck constructs all the
     // parameter environments once for every fn as it goes,
-    // and errors will get reported then; so after typeck we
+    // and errors will get reported then; so outside of type inference we
     // can be sure that no errors should occur.
 
     debug!(

compiler/rustc_trait_selection/src/traits/project.rs

@@ -391,7 +391,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
             // severe performance implications for large opaque types with
             // late-bound regions. See `issue-88862` benchmark.
             ty::Opaque(def_id, substs) if !substs.has_escaping_bound_vars() => {
-                // Only normalize `impl Trait` after type-checking, usually in codegen.
+                // Only normalize `impl Trait` outside of type inference, usually in codegen.
                 match self.param_env.reveal() {
                     Reveal::UserFacing => ty.super_fold_with(self),
 

compiler/rustc_trait_selection/src/traits/query/normalize.rs

@@ -200,7 +200,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
             // severe performance implications for large opaque types with
             // late-bound regions. See `issue-88862` benchmark.
             ty::Opaque(def_id, substs) if !substs.has_escaping_bound_vars() => {
-                // Only normalize `impl Trait` after type-checking, usually in codegen.
+                // Only normalize `impl Trait` outside of type inference, usually in codegen.
                 match self.param_env.reveal() {
                     Reveal::UserFacing => ty.try_super_fold_with(self),
 

compiler/rustc_ty_utils/src/ty.rs

@@ -149,7 +149,7 @@ fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
     // kind of an "idempotent" action, but I'm not sure where would be
     // a better place. In practice, we construct environments for
     // every fn once during type checking, and we'll abort if there
-    // are any errors at that point, so after type checking you can be
+    // are any errors at that point, so outside of type inference you can be
     // sure that this will succeed without errors anyway.
 
     if tcx.sess.opts.debugging_opts.chalk {