Rollup merge of #128110 - veera-sivarajan:bugfix-80173, r=cjgillot

Suggest Replacing Comma with Semicolon in Incorrect Repeat Expressions

Fixes #80173

This PR detects typos in repeat expressions like `["_", 10]` and `vec![String::new(), 10]` and suggests replacing comma with semicolon.

Also, improves code in other place by adding doc comments and making use of a helper function to check if a type implements `Clone`.

References:
1. For `vec![T; N]`: https://doc.rust-lang.org/std/macro.vec.html
2. For `[T; N]`: https://doc.rust-lang.org/std/primitive.array.html

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,
@@ -2094,6 +2094,18 @@ 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