Show the weakness of current tuple normalization

Author: chengluyu

hkmc2/shared/src/test/mlscript/ucs/normalization/UnifyTupleElements.mls

@@ -0,0 +1,108 @@
+:js
+:ucs desugared normalized
+
+:import ../Prelude/Option.mls
+//│ Imported 3 member(s)
+
+fun add_6(x, y) =
+  if [x, y] is
+    [Some(xv), Some(yv)] then xv + yv
+    [Some(xv), None]     then xv
+    [None,     Some(yv)] then yv
+    [None,     None]     then 0
+//│ Desugared:
+//│ >  if
+//│ >    let $scrut@34 = [x@32#666, y@33#666]
+//│ >    $scrut@34 is []=2 and
+//│ >      let $first0@46 = $scrut@34#10.0
+//│ >      let $first1@45 = $scrut@34#11.1
+//│ >      $first0@46 is Some($param0@47) and
+//│ >        let xv@48 = $param0@47#0
+//│ >        $first1@45 is Some($param0@49) and
+//│ >          let yv@50 = $param0@49#0
+//│ >          else globalThis:import#Prelude#666.+‹member:+›(xv@48#666, yv@50#666)
+//│ >    $scrut@34 is []=2 and
+//│ >      let $first0@42 = $scrut@34#7.0
+//│ >      let $first1@41 = $scrut@34#8.1
+//│ >      $first0@42 is Some($param0@43) and
+//│ >        let xv@44 = $param0@43#0
+//│ >        $first1@41 is None then xv@44#666
+//│ >    $scrut@34 is []=2 and
+//│ >      let $first0@38 = $scrut@34#4.0
+//│ >      let $first1@37 = $scrut@34#5.1
+//│ >      $first0@38 is None and $first1@37 is Some($param0@39) and
+//│ >        let yv@40 = $param0@39#0
+//│ >        else yv@40#666
+//│ >    $scrut@34 is []=2 and
+//│ >      let $first0@36 = $scrut@34#1.0
+//│ >      let $first1@35 = $scrut@34#2.1
+//│ >      $first0@36 is None $first1@35 is None then 0
+//│ Normalized:
+//│ >  if
+//│ >    let $scrut@34 = [x@32#666, y@33#666]
+//│ >    $scrut@34 is []=2 and
+//│ >      let $first0@46 = $scrut@34#10.0
+//│ >      let $first1@45 = $scrut@34#11.1
+//│ >      $first0@46 is Some($param0@47) and
+//│ >        let xv@48 = $param0@47#0
+//│ >        $first1@45 is Some($param0@49) and
+//│ >          let yv@50 = $param0@49#0
+//│ >          else globalThis:import#Prelude#666.+‹member:+›(xv@48#666, yv@50#666)
+//│ >        let $first0@42 = $scrut@34#7.0
+//│ >        let $first1@41 = $scrut@34#8.1
+//│ >        $first0@42 is Some($param0@43) and
+//│ >          let xv@44 = $param0@43#0
+//│ >          $first1@41 is None then xv@44#666
+//│ >          let $first0@38 = $scrut@34#4.0
+//│ >          let $first1@37 = $scrut@34#5.1
+//│ >          $first0@38 is None and
+//│ >            $first1@37 is Some($param0@39) and
+//│ >              let yv@40 = $param0@39#0
+//│ >              else yv@40#666
+//│ >            let $first0@36 = $scrut@34#1.0
+//│ >            let $first1@35 = $scrut@34#2.1
+//│ >            $first0@36 is None $first1@35 is None then 0
+//│ >          let $first0@36 = $scrut@34#1.0
+//│ >          let $first1@35 = $scrut@34#2.1
+//│ >          $first0@36 is None $first1@35 is None then 0
+//│ >        let $first0@38 = $scrut@34#4.0
+//│ >        let $first1@37 = $scrut@34#5.1
+//│ >        $first0@38 is None and
+//│ >          $first1@37 is Some($param0@39) and
+//│ >            let yv@40 = $param0@39#0
+//│ >            else yv@40#666
+//│ >          let $first0@36 = $scrut@34#1.0
+//│ >          let $first1@35 = $scrut@34#2.1
+//│ >          $first0@36 is None $first1@35 is None then 0
+//│ >        let $first0@36 = $scrut@34#1.0
+//│ >        let $first1@35 = $scrut@34#2.1
+//│ >        $first0@36 is None $first1@35 is None then 0
+//│ >      let $first0@42 = $scrut@34#7.0
+//│ >      let $first1@41 = $scrut@34#8.1
+//│ >      $first0@42 is Some($param0@43) and
+//│ >        let xv@44 = $param0@43#0
+//│ >        $first1@41 is None then xv@44#666
+//│ >        let $first0@38 = $scrut@34#4.0
+//│ >        let $first1@37 = $scrut@34#5.1
+//│ >        $first0@38 is None and
+//│ >          $first1@37 is Some($param0@39) and
+//│ >            let yv@40 = $param0@39#0
+//│ >            else yv@40#666
+//│ >          let $first0@36 = $scrut@34#1.0
+//│ >          let $first1@35 = $scrut@34#2.1
+//│ >          $first0@36 is None $first1@35 is None then 0
+//│ >        let $first0@36 = $scrut@34#1.0
+//│ >        let $first1@35 = $scrut@34#2.1
+//│ >        $first0@36 is None $first1@35 is None then 0
+//│ >      let $first0@38 = $scrut@34#4.0
+//│ >      let $first1@37 = $scrut@34#5.1
+//│ >      $first0@38 is None and
+//│ >        $first1@37 is Some($param0@39) and
+//│ >          let yv@40 = $param0@39#0
+//│ >          else yv@40#666
+//│ >        let $first0@36 = $scrut@34#1.0
+//│ >        let $first1@35 = $scrut@34#2.1
+//│ >        $first0@36 is None $first1@35 is None then 0
+//│ >      let $first0@36 = $scrut@34#1.0
+//│ >      let $first1@35 = $scrut@34#2.1
+//│ >      $first0@36 is None $first1@35 is None then 0