Auto merge of #103829 - JohnTitor:rollup-o03nzr8, r=JohnTitor

Rollup of 10 pull requests

Successful merges:

 - #103007 (Add better python discovery)
 - #103674 (Update note about unstable split-debuginfo flag.)
 - #103692 (Add `walk_generic_arg`)
 - #103749 (Reduce span of let else irrefutable_let_patterns warning)
 - #103772 (better error for `rustc_strict_coherence` misuse)
 - #103788 (Fix ICE in checking transmutability of NaughtyLenArray)
 - #103793 (rustdoc: add margins to all impl-item toggles, not just methods)
 - #103798 (interpret: move type_name implementation to an interpreter-independent helper file)
 - #103799 (Remove generation of tuple struct fields in the search index)
 - #103805 (Enable RUSTC_BOOTSTRAP for a few steps)

Failed merges:

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

9 files changed, 63 insertions, 28 deletions

diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index 8637d6a7767..b92a6878847 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -7,7 +7,9 @@ use std::convert::TryFrom;
 use rustc_hir::def_id::DefId;
 use rustc_middle::mir::{
     self,
-    interpret::{ConstValue, GlobalId, InterpResult, PointerArithmetic, Scalar},
+    interpret::{
+        Allocation, ConstAllocation, ConstValue, GlobalId, InterpResult, PointerArithmetic, Scalar,
+    },
     BinOp, NonDivergingIntrinsic,
 };
 use rustc_middle::ty;
@@ -23,7 +25,6 @@ use super::{
 };
 
 mod caller_location;
-mod type_name;
 
 fn numeric_intrinsic<Prov>(name: Symbol, bits: u128, kind: Primitive) -> Scalar<Prov> {
     let size = match kind {
@@ -42,6 +43,13 @@ fn numeric_intrinsic<Prov>(name: Symbol, bits: u128, kind: Primitive) -> Scalar<
     Scalar::from_uint(bits_out, size)
 }
 
+/// Directly returns an `Allocation` containing an absolute path representation of the given type.
+pub(crate) fn alloc_type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ConstAllocation<'tcx> {
+    let path = crate::util::type_name(tcx, ty);
+    let alloc = Allocation::from_bytes_byte_aligned_immutable(path.into_bytes());
+    tcx.intern_const_alloc(alloc)
+}
+
 /// The logic for all nullary intrinsics is implemented here. These intrinsics don't get evaluated
 /// inside an `InterpCx` and instead have their value computed directly from rustc internal info.
 pub(crate) fn eval_nullary_intrinsic<'tcx>(
@@ -55,7 +63,7 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
     Ok(match name {
         sym::type_name => {
             ensure_monomorphic_enough(tcx, tp_ty)?;
-            let alloc = type_name::alloc_type_name(tcx, tp_ty);
+            let alloc = alloc_type_name(tcx, tp_ty);
             ConstValue::Slice { data: alloc, start: 0, end: alloc.inner().len() }
         }
         sym::needs_drop => {
diff --git a/compiler/rustc_const_eval/src/util/mod.rs b/compiler/rustc_const_eval/src/util/mod.rs
index 7a05cfd235f..4d0f81a4060 100644
--- a/compiler/rustc_const_eval/src/util/mod.rs
+++ b/compiler/rustc_const_eval/src/util/mod.rs
@@ -4,9 +4,11 @@ mod call_kind;
 pub mod collect_writes;
 mod find_self_call;
 mod might_permit_raw_init;
+mod type_name;
 
 pub use self::aggregate::expand_aggregate;
 pub use self::alignment::is_disaligned;
 pub use self::call_kind::{call_kind, CallDesugaringKind, CallKind};
 pub use self::find_self_call::find_self_call;
 pub use self::might_permit_raw_init::might_permit_raw_init;
+pub use self::type_name::type_name;
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs b/compiler/rustc_const_eval/src/util/type_name.rs
index b15606baee5..221efc6f981 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
+++ b/compiler/rustc_const_eval/src/util/type_name.rs
@@ -1,7 +1,6 @@
 use rustc_data_structures::intern::Interned;
 use rustc_hir::def_id::CrateNum;
 use rustc_hir::definitions::DisambiguatedDefPathData;
-use rustc_middle::mir::interpret::{Allocation, ConstAllocation};
 use rustc_middle::ty::{
     self,
     print::{PrettyPrinter, Print, Printer},
@@ -193,9 +192,6 @@ impl Write for AbsolutePathPrinter<'_> {
     }
 }
 
-/// Directly returns an `Allocation` containing an absolute path representation of the given type.
-pub(crate) fn alloc_type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ConstAllocation<'tcx> {
-    let path = AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path;
-    let alloc = Allocation::from_bytes_byte_aligned_immutable(path.into_bytes());
-    tcx.intern_const_alloc(alloc)
+pub fn type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> String {
+    AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path
 }
diff --git a/compiler/rustc_error_messages/locales/en-US/middle.ftl b/compiler/rustc_error_messages/locales/en-US/middle.ftl
index b9e4499d47f..81d8e8a473b 100644
--- a/compiler/rustc_error_messages/locales/en-US/middle.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/middle.ftl
@@ -27,3 +27,7 @@ middle_values_too_big =
 
 middle_cannot_be_normalized =
     unable to determine layout for `{$ty}` because `{$failure_ty}` cannot be normalized
+
+middle_strict_coherence_needs_negative_coherence =
+    to use `strict_coherence` on this trait, the `with_negative_coherence` feature must be enabled
+    .label = due to this attribute
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index be77e6fd36a..9ee5e25c9bf 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -410,12 +410,7 @@ pub trait Visitor<'v>: Sized {
         walk_inf(self, inf);
     }
     fn visit_generic_arg(&mut self, generic_arg: &'v GenericArg<'v>) {
-        match generic_arg {
-            GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
-            GenericArg::Type(ty) => self.visit_ty(ty),
-            GenericArg::Const(ct) => self.visit_anon_const(&ct.value),
-            GenericArg::Infer(inf) => self.visit_infer(inf),
-        }
+        walk_generic_arg(self, generic_arg);
     }
     fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
         walk_lifetime(self, lifetime)
@@ -480,6 +475,15 @@ pub fn walk_label<'v, V: Visitor<'v>>(visitor: &mut V, label: &'v Label) {
     visitor.visit_ident(label.ident);
 }
 
+pub fn walk_generic_arg<'v, V: Visitor<'v>>(visitor: &mut V, generic_arg: &'v GenericArg<'v>) {
+    match generic_arg {
+        GenericArg::Lifetime(lt) => visitor.visit_lifetime(lt),
+        GenericArg::Type(ty) => visitor.visit_ty(ty),
+        GenericArg::Const(ct) => visitor.visit_anon_const(&ct.value),
+        GenericArg::Infer(inf) => visitor.visit_infer(inf),
+    }
+}
+
 pub fn walk_lifetime<'v, V: Visitor<'v>>(visitor: &mut V, lifetime: &'v Lifetime) {
     visitor.visit_id(lifetime.hir_id);
     match lifetime.name {
diff --git a/compiler/rustc_middle/src/error.rs b/compiler/rustc_middle/src/error.rs
index a7a7ac0599d..43903e6739f 100644
--- a/compiler/rustc_middle/src/error.rs
+++ b/compiler/rustc_middle/src/error.rs
@@ -55,3 +55,12 @@ pub struct ConstEvalNonIntError {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(middle_strict_coherence_needs_negative_coherence)]
+pub(crate) struct StrictCoherenceNeedsNegativeCoherence {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub attr_span: Option<Span>,
+}
diff --git a/compiler/rustc_middle/src/traits/specialization_graph.rs b/compiler/rustc_middle/src/traits/specialization_graph.rs
index 0a2819feecf..f1c21588261 100644
--- a/compiler/rustc_middle/src/traits/specialization_graph.rs
+++ b/compiler/rustc_middle/src/traits/specialization_graph.rs
@@ -1,3 +1,4 @@
+use crate::error::StrictCoherenceNeedsNegativeCoherence;
 use crate::ty::fast_reject::SimplifiedType;
 use crate::ty::visit::TypeVisitable;
 use crate::ty::{self, TyCtxt};
@@ -65,9 +66,21 @@ impl OverlapMode {
 
         if with_negative_coherence {
             if strict_coherence { OverlapMode::Strict } else { OverlapMode::WithNegative }
-        } else if strict_coherence {
-            bug!("To use strict_coherence you need to set with_negative_coherence feature flag");
         } else {
+            if strict_coherence {
+                let attr_span = trait_id
+                    .as_local()
+                    .into_iter()
+                    .flat_map(|local_def_id| {
+                        tcx.hir().attrs(tcx.hir().local_def_id_to_hir_id(local_def_id))
+                    })
+                    .find(|attr| attr.has_name(sym::rustc_strict_coherence))
+                    .map(|attr| attr.span);
+                tcx.sess.emit_err(StrictCoherenceNeedsNegativeCoherence {
+                    span: tcx.def_span(trait_id),
+                    attr_span,
+                });
+            }
             OverlapMode::Stable
         }
     }
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index a9e5e438cf5..93a3dd8962a 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -79,7 +79,10 @@ impl<'tcx> Visitor<'tcx> for MatchVisitor<'_, '_, 'tcx> {
         intravisit::walk_local(self, loc);
         let els = loc.els;
         if let Some(init) = loc.init && els.is_some() {
-            self.check_let(&loc.pat, init, loc.span);
+            // Build a span without the else { ... } as we don't want to underline
+            // the entire else block in the IDE setting.
+            let span = loc.span.with_hi(init.span.hi());
+            self.check_let(&loc.pat, init, span);
         }
 
         let (msg, sp) = match loc.source {
@@ -630,11 +633,6 @@ fn irrefutable_let_patterns(
     count: usize,
     span: Span,
 ) {
-    let span = match source {
-        LetSource::LetElse(span) => span,
-        _ => span,
-    };
-
     macro_rules! emit_diag {
         (
             $lint:expr,
@@ -680,7 +678,7 @@ fn irrefutable_let_patterns(
                 "removing the guard and adding a `let` inside the match arm"
             );
         }
-        LetSource::LetElse(..) => {
+        LetSource::LetElse => {
             emit_diag!(
                 lint,
                 "`let...else`",
@@ -1127,7 +1125,7 @@ pub enum LetSource {
     GenericLet,
     IfLet,
     IfLetGuard,
-    LetElse(Span),
+    LetElse,
     WhileLet,
 }
 
@@ -1156,8 +1154,8 @@ fn let_source_parent(tcx: TyCtxt<'_>, parent: HirId, pat_id: Option<HirId>) -> L
     let parent_parent = hir.get_parent_node(parent);
     let parent_parent_node = hir.get(parent_parent);
     match parent_parent_node {
-        hir::Node::Stmt(hir::Stmt { kind: hir::StmtKind::Local(_), span, .. }) => {
-            return LetSource::LetElse(*span);
+        hir::Node::Stmt(hir::Stmt { kind: hir::StmtKind::Local(_), .. }) => {
+            return LetSource::LetElse;
         }
         hir::Node::Arm(hir::Arm { guard: Some(hir::Guard::If(_)), .. }) => {
             return LetSource::IfLetGuard;
diff --git a/compiler/rustc_transmute/src/layout/tree.rs b/compiler/rustc_transmute/src/layout/tree.rs
index acd4fa63d78..2bc6bc1fc23 100644
--- a/compiler/rustc_transmute/src/layout/tree.rs
+++ b/compiler/rustc_transmute/src/layout/tree.rs
@@ -284,7 +284,8 @@ pub(crate) mod rustc {
                 }
 
                 ty::Array(ty, len) => {
-                    let len = len.try_eval_usize(tcx, ParamEnv::reveal_all()).unwrap();
+                    let len =
+                        len.try_eval_usize(tcx, ParamEnv::reveal_all()).ok_or(Err::Unspecified)?;
                     let elt = Tree::from_ty(*ty, tcx)?;
                     Ok(std::iter::repeat(elt)
                         .take(len as usize)