Rollup of 7 pull requests

compiler/rustc_hir/src/hir.rs

@@ -7,7 +7,7 @@ use rustc_ast::token::CommentKind;
 use rustc_ast::util::parser::{AssocOp, ExprPrecedence};
 use rustc_ast::{
     self as ast, AttrId, AttrStyle, DelimArgs, FloatTy, InlineAsmOptions, InlineAsmTemplatePiece,
-    IntTy, Label, LitKind, MetaItemInner, MetaItemLit, TraitObjectSyntax, UintTy,
+    IntTy, Label, LitIntType, LitKind, MetaItemInner, MetaItemLit, TraitObjectSyntax, UintTy,
 };
 pub use rustc_ast::{
     BinOp, BinOpKind, BindingMode, BorrowKind, BoundConstness, BoundPolarity, ByRef, CaptureBy,
@@ -2074,6 +2074,18 @@ impl Expr<'_> {
         }
     }
 
+    /// Check if expression is an integer literal that can be used
+    /// where `usize` is expected.
+    pub fn is_size_lit(&self) -> bool {
+        matches!(
+            self.kind,
+            ExprKind::Lit(Lit {
+                node: LitKind::Int(_, LitIntType::Unsuffixed | LitIntType::Unsigned(UintTy::Usize)),
+                ..
+            })
+        )
+    }
+
     /// If `Self.kind` is `ExprKind::DropTemps(expr)`, drill down until we get a non-`DropTemps`
     /// `Expr`. This is used in suggestions to ignore this `ExprKind` as it is semantically
     /// silent, only signaling the ownership system. By doing this, suggestions that check the

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -35,7 +35,7 @@ use rustc_hir::{self as hir, AnonConst, GenericArg, GenericArgs, HirId};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::middle::stability::AllowUnstable;
-use rustc_middle::mir::interpret::{LitToConstError, LitToConstInput};
+use rustc_middle::mir::interpret::LitToConstInput;
 use rustc_middle::ty::fold::fold_regions;
 use rustc_middle::ty::print::PrintPolyTraitRefExt as _;
 use rustc_middle::ty::{
@@ -2262,25 +2262,11 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             _ => None,
         };
 
-        if let Some(lit_input) = lit_input {
-            // If an error occurred, ignore that it's a literal and leave reporting the error up to
-            // mir.
-            match tcx.at(expr.span).lit_to_const(lit_input) {
-                Ok(c) => return Some(c),
-                Err(_) if lit_input.ty.has_aliases() => {
-                    // allow the `ty` to be an alias type, though we cannot handle it here
-                    return None;
-                }
-                Err(e) => {
-                    tcx.dcx().span_delayed_bug(
-                        expr.span,
-                        format!("try_lower_anon_const_lit: couldn't lit_to_const {e:?}"),
-                    );
-                }
-            }
-        }
-
-        None
+        lit_input
+            // Allow the `ty` to be an alias type, though we cannot handle it here, we just go through
+            // the more expensive anon const code path.
+            .filter(|l| !l.ty.has_aliases())
+            .map(|l| tcx.at(expr.span).lit_to_const(l))
     }
 
     fn lower_delegation_ty(&self, idx: hir::InferDelegationKind) -> Ty<'tcx> {
@@ -2460,13 +2446,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                                 hir::ExprKind::Lit(lit) => {
                                     let lit_input =
                                         LitToConstInput { lit: &lit.node, ty, neg: neg.is_some() };
-                                    let ct = match tcx.lit_to_const(lit_input) {
-                                        Ok(c) => c,
-                                        Err(LitToConstError::Reported(err)) => {
-                                            ty::Const::new_error(tcx, err)
-                                        }
-                                        Err(LitToConstError::TypeError) => todo!(),
-                                    };
+                                    let ct = tcx.lit_to_const(lit_input);
                                     (ct, ty)
                                 }
 

compiler/rustc_hir_typeck/messages.ftl

@@ -165,6 +165,8 @@ hir_typeck_remove_semi_for_coerce_ret = the `match` arms can conform to this ret
 hir_typeck_remove_semi_for_coerce_semi = the `match` is a statement because of this semicolon, consider removing it
 hir_typeck_remove_semi_for_coerce_suggestion = remove this semicolon
 
+hir_typeck_replace_comma_with_semicolon = replace the comma with a semicolon to create {$descr}
+
 hir_typeck_return_stmt_outside_of_fn_body =
     {$statement_kind} statement outside of function body
     .encl_body_label = the {$statement_kind} is part of this body...

compiler/rustc_hir_typeck/src/demand.rs

@@ -30,7 +30,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         if expr_ty == expected {
             return;
         }
-
         self.annotate_alternative_method_deref(err, expr, error);
         self.explain_self_literal(err, expr, expected, expr_ty);
 
@@ -39,6 +38,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             || self.suggest_missing_unwrap_expect(err, expr, expected, expr_ty)
             || self.suggest_remove_last_method_call(err, expr, expected)
             || self.suggest_associated_const(err, expr, expected)
+            || self.suggest_semicolon_in_repeat_expr(err, expr, expr_ty)
             || self.suggest_deref_ref_or_into(err, expr, expected, expr_ty, expected_ty_expr)
             || self.suggest_option_to_bool(err, expr, expr_ty, expected)
             || self.suggest_compatible_variants(err, expr, expected, expr_ty)

compiler/rustc_hir_typeck/src/errors.rs

@@ -846,3 +846,16 @@ pub(crate) struct PassFnItemToVariadicFunction {
     pub sugg_span: Span,
     pub replace: String,
 }
+
+#[derive(Subdiagnostic)]
+#[suggestion(
+    hir_typeck_replace_comma_with_semicolon,
+    applicability = "machine-applicable",
+    style = "verbose",
+    code = "; "
+)]
+pub(crate) struct ReplaceCommaWithSemicolon {
+    #[primary_span]
+    pub comma_span: Span,
+    pub descr: &'static str,
+}

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1320,14 +1320,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let span = expr.span.shrink_to_hi();
                 let subdiag = if self.type_is_copy_modulo_regions(self.param_env, ty) {
                     errors::OptionResultRefMismatch::Copied { span, def_path }
-                } else if let Some(clone_did) = self.tcx.lang_items().clone_trait()
-                    && rustc_trait_selection::traits::type_known_to_meet_bound_modulo_regions(
-                        self,
-                        self.param_env,
-                        ty,
-                        clone_did,
-                    )
-                {
+                } else if self.type_is_clone_modulo_regions(self.param_env, ty) {
                     errors::OptionResultRefMismatch::Cloned { span, def_path }
                 } else {
                     return false;
@@ -2182,6 +2175,87 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    /// Suggest replacing comma with semicolon in incorrect repeat expressions
+    /// like `["_", 10]` or `vec![String::new(), 10]`.
+    pub(crate) fn suggest_semicolon_in_repeat_expr(
+        &self,
+        err: &mut Diag<'_>,
+        expr: &hir::Expr<'_>,
+        expr_ty: Ty<'tcx>,
+    ) -> bool {
+        // Check if `expr` is contained in array of two elements
+        if let hir::Node::Expr(array_expr) = self.tcx.parent_hir_node(expr.hir_id)
+            && let hir::ExprKind::Array(elements) = array_expr.kind
+            && let [first, second] = &elements[..]
+            && second.hir_id == expr.hir_id
+        {
+            // Span between the two elements of the array
+            let comma_span = first.span.between(second.span);
+
+            // Check if `expr` is a constant value of type `usize`.
+            // This can only detect const variable declarations and
+            // calls to const functions.
+
+            // Checking this here instead of rustc_hir::hir because
+            // this check needs access to `self.tcx` but rustc_hir
+            // has no access to `TyCtxt`.
+            let expr_is_const_usize = expr_ty.is_usize()
+                && match expr.kind {
+                    ExprKind::Path(QPath::Resolved(
+                        None,
+                        Path { res: Res::Def(DefKind::Const, _), .. },
+                    )) => true,
+                    ExprKind::Call(
+                        Expr {
+                            kind:
+                                ExprKind::Path(QPath::Resolved(
+                                    None,
+                                    Path { res: Res::Def(DefKind::Fn, fn_def_id), .. },
+                                )),
+                            ..
+                        },
+                        _,
+                    ) => self.tcx.is_const_fn(*fn_def_id),
+                    _ => false,
+                };
+
+            // Type of the first element is guaranteed to be checked
+            // when execution reaches here because `mismatched types`
+            // error occurs only when type of second element of array
+            // is not the same as type of first element.
+            let first_ty = self.typeck_results.borrow().expr_ty(first);
+
+            // `array_expr` is from a macro `vec!["a", 10]` if
+            // 1. array expression's span is imported from a macro
+            // 2. first element of array implements `Clone` trait
+            // 3. second element is an integer literal or is an expression of `usize` like type
+            if self.tcx.sess.source_map().is_imported(array_expr.span)
+                && self.type_is_clone_modulo_regions(self.param_env, first_ty)
+                && (expr.is_size_lit() || expr_ty.is_usize_like())
+            {
+                err.subdiagnostic(errors::ReplaceCommaWithSemicolon {
+                    comma_span,
+                    descr: "a vector",
+                });
+                return true;
+            }
+
+            // `array_expr` is from an array `["a", 10]` if
+            // 1. first element of array implements `Copy` trait
+            // 2. second element is an integer literal or is a const value of type `usize`
+            if self.type_is_copy_modulo_regions(self.param_env, first_ty)
+                && (expr.is_size_lit() || expr_is_const_usize)
+            {
+                err.subdiagnostic(errors::ReplaceCommaWithSemicolon {
+                    comma_span,
+                    descr: "an array",
+                });
+                return true;
+            }
+        }
+        false
+    }
+
     /// If the expected type is an enum (Issue #55250) with any variants whose
     /// sole field is of the found type, suggest such variants. (Issue #42764)
     pub(crate) fn suggest_compatible_variants(

compiler/rustc_middle/src/mir/interpret/mod.rs

@@ -16,7 +16,6 @@ use rustc_abi::{AddressSpace, Align, Endian, HasDataLayout, Size};
 use rustc_ast::{LitKind, Mutability};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lock;
-use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_macros::{HashStable, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable};
@@ -84,16 +83,6 @@ pub struct LitToConstInput<'tcx> {
     pub neg: bool,
 }
 
-/// Error type for `tcx.lit_to_const`.
-#[derive(Copy, Clone, Debug, Eq, PartialEq, HashStable)]
-pub enum LitToConstError {
-    /// The literal's inferred type did not match the expected `ty` in the input.
-    /// This is used for graceful error handling (`span_delayed_bug`) in
-    /// type checking (`Const::from_anon_const`).
-    TypeError,
-    Reported(ErrorGuaranteed),
-}
-
 #[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]
 pub struct AllocId(pub NonZero<u64>);
 

compiler/rustc_middle/src/query/erase.rs

@@ -141,14 +141,6 @@ impl EraseType for Result<rustc_abi::TyAndLayout<'_, Ty<'_>>, &ty::layout::Layou
     >()];
 }
 
-impl EraseType for Result<ty::Const<'_>, mir::interpret::LitToConstError> {
-    type Result = [u8; size_of::<Result<ty::Const<'static>, mir::interpret::LitToConstError>>()];
-}
-
-impl EraseType for Result<mir::Const<'_>, mir::interpret::LitToConstError> {
-    type Result = [u8; size_of::<Result<mir::Const<'static>, mir::interpret::LitToConstError>>()];
-}
-
 impl EraseType for Result<mir::ConstAlloc<'_>, mir::interpret::ErrorHandled> {
     type Result = [u8; size_of::<Result<mir::ConstAlloc<'static>, mir::interpret::ErrorHandled>>()];
 }
@@ -296,7 +288,6 @@ trivial! {
     rustc_middle::mir::interpret::AllocId,
     rustc_middle::mir::interpret::CtfeProvenance,
     rustc_middle::mir::interpret::ErrorHandled,
-    rustc_middle::mir::interpret::LitToConstError,
     rustc_middle::thir::ExprId,
     rustc_middle::traits::CodegenObligationError,
     rustc_middle::traits::EvaluationResult,

compiler/rustc_middle/src/query/mod.rs

@@ -57,7 +57,7 @@ use crate::middle::resolve_bound_vars::{ObjectLifetimeDefault, ResolveBoundVars,
 use crate::middle::stability::{self, DeprecationEntry};
 use crate::mir::interpret::{
     EvalStaticInitializerRawResult, EvalToAllocationRawResult, EvalToConstValueResult,
-    EvalToValTreeResult, GlobalId, LitToConstError, LitToConstInput,
+    EvalToValTreeResult, GlobalId, LitToConstInput,
 };
 use crate::mir::mono::{CodegenUnit, CollectionMode, MonoItem};
 use crate::query::erase::{Erase, erase, restore};
@@ -1268,7 +1268,7 @@ rustc_queries! {
     // FIXME get rid of this with valtrees
     query lit_to_const(
         key: LitToConstInput<'tcx>
-    ) -> Result<ty::Const<'tcx>, LitToConstError> {
+    ) -> ty::Const<'tcx> {
         desc { "converting literal to const" }
     }
 

compiler/rustc_middle/src/ty/mod.rs

@@ -1417,8 +1417,8 @@ impl Hash for FieldDef {
 impl<'tcx> FieldDef {
     /// Returns the type of this field. The resulting type is not normalized. The `arg` is
     /// typically obtained via the second field of [`TyKind::Adt`].
-    pub fn ty(&self, tcx: TyCtxt<'tcx>, arg: GenericArgsRef<'tcx>) -> Ty<'tcx> {
-        tcx.type_of(self.did).instantiate(tcx, arg)
+    pub fn ty(&self, tcx: TyCtxt<'tcx>, args: GenericArgsRef<'tcx>) -> Ty<'tcx> {
+        tcx.type_of(self.did).instantiate(tcx, args)
     }
 
     /// Computes the `Ident` of this variant by looking up the `Span`

compiler/rustc_middle/src/ty/sty.rs

@@ -27,7 +27,7 @@ use crate::infer::canonical::Canonical;
 use crate::ty::InferTy::*;
 use crate::ty::{
     self, AdtDef, BoundRegionKind, Discr, GenericArg, GenericArgs, GenericArgsRef, List, ParamEnv,
-    Region, Ty, TyCtxt, TypeFlags, TypeSuperVisitable, TypeVisitable, TypeVisitor,
+    Region, Ty, TyCtxt, TypeFlags, TypeSuperVisitable, TypeVisitable, TypeVisitor, UintTy,
 };
 
 // Re-export and re-parameterize some `I = TyCtxt<'tcx>` types here
@@ -1017,6 +1017,18 @@ impl<'tcx> Ty<'tcx> {
         }
     }
 
+    /// Check if type is an `usize`.
+    #[inline]
+    pub fn is_usize(self) -> bool {
+        matches!(self.kind(), Uint(UintTy::Usize))
+    }
+
+    /// Check if type is an `usize` or an integral type variable.
+    #[inline]
+    pub fn is_usize_like(self) -> bool {
+        matches!(self.kind(), Uint(UintTy::Usize) | Infer(IntVar(_)))
+    }
+
     #[inline]
     pub fn is_never(self) -> bool {
         matches!(self.kind(), Never)