Auto merge of #98307 - matthiaskrgr:rollup-rb3huha, r=matthiaskrgr

Rollup of 4 pull requests

Successful merges:

 - #98235 (Drop magic value 3 from code)
 - #98267 (Don't omit comma when suggesting wildcard arm after macro expr)
 - #98276 (Mention formatting macros when encountering `ArgumentV1` method in const)
 - #98296 (Add a link to the unstable book page on Generator doc comment)

Failed merges:

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

Author: bors

compiler/rustc_const_eval/src/transform/check_consts/ops.rs

@@ -10,7 +10,8 @@ use rustc_middle::mir;
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::{
-    suggest_constraining_type_param, Adt, Closure, FnDef, FnPtr, Param, TraitPredicate, Ty,
+    suggest_constraining_type_param, Adt, Closure, DefIdTree, FnDef, FnPtr, Param, TraitPredicate,
+    Ty,
 };
 use rustc_middle::ty::{Binder, BoundConstness, ImplPolarity, TraitRef};
 use rustc_session::parse::feature_err;
@@ -300,6 +301,15 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
                 diag_trait(&mut err, self_ty, tcx.lang_items().deref_trait().unwrap());
                 err
             }
+            _ if tcx.opt_parent(callee) == tcx.get_diagnostic_item(sym::ArgumentV1Methods) => {
+                struct_span_err!(
+                    ccx.tcx.sess,
+                    span,
+                    E0015,
+                    "cannot call non-const formatting macro in {}s",
+                    ccx.const_kind(),
+                )
+            }
             _ => struct_span_err!(
                 ccx.tcx.sess,
                 span,

compiler/rustc_middle/src/mir/spanview.rs

@@ -667,7 +667,7 @@ fn trim_span_hi(span: Span, to_pos: BytePos) -> Span {
 fn fn_span<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Span {
     let fn_decl_span = tcx.def_span(def_id);
     if let Some(body_span) = hir_body(tcx, def_id).map(|hir_body| hir_body.value.span) {
-        if fn_decl_span.ctxt() == body_span.ctxt() { fn_decl_span.to(body_span) } else { body_span }
+        if fn_decl_span.eq_ctxt(body_span) { fn_decl_span.to(body_span) } else { body_span }
     } else {
         fn_decl_span
     }

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -803,7 +803,7 @@ fn non_exhaustive_match<'p, 'tcx>(
     let mut suggestion = None;
     let sm = cx.tcx.sess.source_map();
     match arms {
-        [] if sp.ctxt() == expr_span.ctxt() => {
+        [] if sp.eq_ctxt(expr_span) => {
             // Get the span for the empty match body `{}`.
             let (indentation, more) = if let Some(snippet) = sm.indentation_before(sp) {
                 (format!("\n{}", snippet), "    ")
@@ -821,24 +821,36 @@ fn non_exhaustive_match<'p, 'tcx>(
             ));
         }
         [only] => {
-            let pre_indentation = if let (Some(snippet), true) = (
-                sm.indentation_before(only.span),
-                sm.is_multiline(sp.shrink_to_hi().with_hi(only.span.lo())),
-            ) {
-                format!("\n{}", snippet)
+            let (pre_indentation, is_multiline) = if let Some(snippet) = sm.indentation_before(only.span)
+                && let Ok(with_trailing) = sm.span_extend_while(only.span, |c| c.is_whitespace() || c == ',')
+                && sm.is_multiline(with_trailing)
+            {
+                (format!("\n{}", snippet), true)
+            } else {
+                (" ".to_string(), false)
+            };
+            let comma = if matches!(only.body.kind, hir::ExprKind::Block(..))
+                && only.span.eq_ctxt(only.body.span)
+                && is_multiline
+            {
+                ""
             } else {
-                " ".to_string()
+                ","
             };
-            let comma = if matches!(only.body.kind, hir::ExprKind::Block(..)) { "" } else { "," };
             suggestion = Some((
                 only.span.shrink_to_hi(),
                 format!("{}{}{} => todo!()", comma, pre_indentation, pattern),
             ));
         }
-        [.., prev, last] if prev.span.ctxt() == last.span.ctxt() => {
+        [.., prev, last] if prev.span.eq_ctxt(last.span) => {
             if let Ok(snippet) = sm.span_to_snippet(prev.span.between(last.span)) {
-                let comma =
-                    if matches!(last.body.kind, hir::ExprKind::Block(..)) { "" } else { "," };
+                let comma = if matches!(last.body.kind, hir::ExprKind::Block(..))
+                    && last.span.eq_ctxt(last.body.span)
+                {
+                    ""
+                } else {
+                    ","
+                };
                 suggestion = Some((
                     last.span.shrink_to_hi(),
                     format!(

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -121,7 +121,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
 
         let source_file = source_map.lookup_source_file(body_span.lo());
         let fn_sig_span = match some_fn_sig.filter(|fn_sig| {
-            fn_sig.span.ctxt() == body_span.ctxt()
+            fn_sig.span.eq_ctxt(body_span)
                 && Lrc::ptr_eq(&source_file, &source_map.lookup_source_file(fn_sig.span.lo()))
         }) {
             Some(fn_sig) => fn_sig.span.with_hi(body_span.lo()),

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -195,7 +195,7 @@ impl CoverageSpan {
             .expn_span
             .parent_callsite()
             .unwrap_or_else(|| bug!("macro must have a parent"))
-            .ctxt() == body_span.ctxt()
+            .eq_ctxt(body_span)
         {
             return Some(current_macro);
         }

compiler/rustc_mir_transform/src/generator.rs

@@ -195,6 +195,11 @@ const RETURNED: usize = GeneratorSubsts::RETURNED;
 /// Generator has panicked and is poisoned.
 const POISONED: usize = GeneratorSubsts::POISONED;
 
+/// Number of variants to reserve in generator state. Corresponds to
+/// `UNRESUMED` (beginning of a generator) and `RETURNED`/`POISONED`
+/// (end of a generator) states.
+const RESERVED_VARIANTS: usize = 3;
+
 /// A `yield` point in the generator.
 struct SuspensionPoint<'tcx> {
     /// State discriminant used when suspending or resuming at this point.
@@ -345,7 +350,7 @@ impl<'tcx> MutVisitor<'tcx> for TransformVisitor<'tcx> {
             data.statements.extend(self.make_state(state_idx, v, source_info));
             let state = if let Some((resume, mut resume_arg)) = resume {
                 // Yield
-                let state = 3 + self.suspension_points.len();
+                let state = RESERVED_VARIANTS + self.suspension_points.len();
 
                 // The resume arg target location might itself be remapped if its base local is
                 // live across a yield.
@@ -792,7 +797,6 @@ fn compute_layout<'tcx>(
     // Leave empty variants for the UNRESUMED, RETURNED, and POISONED states.
     // In debuginfo, these will correspond to the beginning (UNRESUMED) or end
     // (RETURNED, POISONED) of the function.
-    const RESERVED_VARIANTS: usize = 3;
     let body_span = body.source_scopes[OUTERMOST_SOURCE_SCOPE].span;
     let mut variant_source_info: IndexVec<VariantIdx, SourceInfo> = [
         SourceInfo::outermost(body_span.shrink_to_lo()),

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1894,7 +1894,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         let names = rib
             .bindings
             .iter()
-            .filter(|(id, _)| id.span.ctxt() == label.span.ctxt())
+            .filter(|(id, _)| id.span.eq_ctxt(label.span))
             .map(|(id, _)| id.name)
             .collect::<Vec<Symbol>>();
 

compiler/rustc_span/src/lib.rs

@@ -537,6 +537,9 @@ impl Span {
     pub fn ctxt(self) -> SyntaxContext {
         self.data_untracked().ctxt
     }
+    pub fn eq_ctxt(self, other: Span) -> bool {
+        self.data_untracked().ctxt == other.data_untracked().ctxt
+    }
     #[inline]
     pub fn with_ctxt(self, ctxt: SyntaxContext) -> Span {
         self.data_untracked().with_ctxt(ctxt)

compiler/rustc_span/src/symbol.rs

@@ -131,6 +131,7 @@ symbols! {
         Arc,
         Argument,
         ArgumentV1,
+        ArgumentV1Methods,
         Arguments,
         AsMut,
         AsRef,
@@ -1641,7 +1642,7 @@ impl Ident {
 
 impl PartialEq for Ident {
     fn eq(&self, rhs: &Self) -> bool {
-        self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
+        self.name == rhs.name && self.span.eq_ctxt(rhs.span)
     }
 }
 

library/core/src/fmt/mod.rs

@@ -320,6 +320,7 @@ macro_rules! arg_new {
     };
 }
 
+#[rustc_diagnostic_item = "ArgumentV1Methods"]
 impl<'a> ArgumentV1<'a> {
     #[doc(hidden)]
     #[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]

library/core/src/ops/generator.rs

@@ -61,9 +61,10 @@ pub enum GeneratorState<Y, R> {
 /// }
 /// ```
 ///
-/// More documentation of generators can be found in the unstable book.
+/// More documentation of generators can be found in the [unstable book].
 ///
 /// [RFC 2033]: https://github.com/rust-lang/rfcs/pull/2033
+/// [unstable book]: ../../unstable-book/language-features/generators.html
 #[lang = "generator"]
 #[unstable(feature = "generator_trait", issue = "43122")]
 #[fundamental]

src/test/ui/consts/const-eval/format.rs

@@ -0,0 +1,21 @@
+const fn failure() {
+    panic!("{:?}", 0);
+    //~^ ERROR cannot call non-const formatting macro in constant functions
+    //~| ERROR erroneous constant used
+    //~| ERROR erroneous constant used
+    //~| WARN this was previously accepted by the compiler
+    //~| WARN this was previously accepted by the compiler
+}
+
+const fn print() {
+    println!("{:?}", 0);
+    //~^ ERROR cannot call non-const formatting macro in constant functions
+    //~| ERROR `Arguments::<'a>::new_v1` is not yet stable as a const fn
+    //~| ERROR cannot call non-const fn `_print` in constant functions
+    //~| ERROR erroneous constant used
+    //~| ERROR erroneous constant used
+    //~| WARN this was previously accepted by the compiler
+    //~| WARN this was previously accepted by the compiler
+}
+
+fn main() {}

src/test/ui/consts/const-eval/format.stderr

@@ -0,0 +1,78 @@
+error[E0015]: cannot call non-const formatting macro in constant functions
+  --> $DIR/format.rs:2:20
+   |
+LL |     panic!("{:?}", 0);
+   |                    ^
+   |
+   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+   = note: this error originates in the macro `$crate::const_format_args` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0015]: cannot call non-const formatting macro in constant functions
+  --> $DIR/format.rs:11:22
+   |
+LL |     println!("{:?}", 0);
+   |                      ^
+   |
+   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+   = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `Arguments::<'a>::new_v1` is not yet stable as a const fn
+  --> $DIR/format.rs:11:5
+   |
+LL |     println!("{:?}", 0);
+   |     ^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(const_fmt_arguments_new)]` to the crate attributes to enable
+   = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0015]: cannot call non-const fn `_print` in constant functions
+  --> $DIR/format.rs:11:5
+   |
+LL |     println!("{:?}", 0);
+   |     ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+   = note: this error originates in the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: erroneous constant used
+  --> $DIR/format.rs:2:12
+   |
+LL |     panic!("{:?}", 0);
+   |            ^^^^^^ referenced constant has errors
+   |
+   = note: `#[deny(const_err)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+
+error: erroneous constant used
+  --> $DIR/format.rs:2:20
+   |
+LL |     panic!("{:?}", 0);
+   |                    ^ referenced constant has errors
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+   = note: this error originates in the macro `$crate::const_format_args` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: erroneous constant used
+  --> $DIR/format.rs:11:14
+   |
+LL |     println!("{:?}", 0);
+   |              ^^^^^^ referenced constant has errors
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+
+error: erroneous constant used
+  --> $DIR/format.rs:11:22
+   |
+LL |     println!("{:?}", 0);
+   |                      ^ referenced constant has errors
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #71800 <https://github.com/rust-lang/rust/issues/71800>
+   = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0015`.