Detect different borrowing in different sub-expressions the same expression and suggest borrowing when applicable

error[E0308]: mismatched types
    --> compiler/rustc_middle/src/ty/context.rs:3212:73
     |
3210 |         match expr.kind {
     |               --------- this expression has type `rustc_hir::ExprKind<'_>`
3211 |             hir::ExprKind::Path(qpath)
     |                                 ----- first introduced with type `rustc_hir::QPath<'_>` here
3212 |             | hir::ExprKind::Call(hir::Expr { kind: hir::ExprKind::Path(qpath), .. }, []) => {
     |                                                                         ^^^^^ expected `QPath<'_>`, found `&QPath<'_>`
     |
     = note: in the same arm, a binding must have the same type in all alternatives

The above should suggest match &expr.kind.

Start at compiler/rustc_middle/src/ty/context.rs:3212 and inspect the match over expr.kind shown in the E0308 report. Use the reported example to verify the completed behavior: the compiler suggests matching on &expr.kind when alternatives bind different borrowing levels.