Alpha-equivalence for recursive let-bindings gives false positives

I was looking at the Eq (DeBruijn CoreExpr) instance and I noticed that the types of recursive let-bindings aren't checked for alpha-equivalence:

https://gitlab.haskell.org/ghc/ghc/-/blob/master/compiler/GHC/Core/Map/Expr.hs#L166-174

    go (Let (Rec ps1) e1) (Let (Rec ps2) e2)
      = equalLength ps1 ps2
      && D env1' rs1 == D env2' rs2
      && D env1' e1  == D env2' e2
      where
        (bs1,rs1) = unzip ps1
        (bs2,rs2) = unzip ps2
        env1' = extendCMEs env1 bs1
        env2' = extendCMEs env2 bs2

But that means that:

let (x :: Int) = x in x

and

let (y :: Bool) = y in y

are considered alpha-equivalent, whilst they're not.

The same mistake is made in eqExpr https://gitlab.haskell.org/ghc/ghc/-/blob/master/compiler/GHC/Core/Utils.hs#L2148-2154

    go env (Let (Rec ps1) e1) (Let (Rec ps2) e2)
      = equalLength ps1 ps2
      && all2 (go env') rs1 rs2 && go env' e1 e2
      where
        (bs1,rs1) = unzip ps1
        (bs2,rs2) = unzip ps2
        env' = rnBndrs2 env bs1 bs2

Note that the types don't have checked for non-recursive bindings (and aren't checked): when the RHSs are the same, the types of the bindings must be the same.