Fix scala-js#4442: Properly type js.If and js.TryCatch in statement position

gzm0 · sjrd · commit e440de9b54fa · 2021-06-07T11:50:22.000+02:00
In statement position, they must always be typed as NoType, since
their children might be typed as such.

We condition the deserialization hack introduced in the parent
commit so that it only applies to old code.
diff --git a/compiler/src/main/scala/org/scalajs/nscplugin/GenJSCode.scala b/compiler/src/main/scala/org/scalajs/nscplugin/GenJSCode.scala
@@ -2225,8 +2225,12 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
           }
 
         case If(cond, thenp, elsep) =>
+          val tpe =
+            if (isStat) jstpe.NoType
+            else toIRType(tree.tpe)
+
           js.If(genExpr(cond), genStatOrExpr(thenp, isStat),
-              genStatOrExpr(elsep, isStat))(toIRType(tree.tpe))
+              genStatOrExpr(elsep, isStat))(tpe)
 
         case Return(expr) =>
           js.Return(toIRType(expr.tpe) match {
@@ -2690,7 +2694,10 @@ abstract class GenJSCode[G <: Global with Singleton](val global: G)
       val Try(block, catches, finalizer) = tree
 
       val blockAST = genStatOrExpr(block, isStat)
-      val resultType = toIRType(tree.tpe)
+
+      val resultType =
+        if (isStat) jstpe.NoType
+        else toIRType(tree.tpe)
 
       val handled =
         if (catches.isEmpty) blockAST
diff --git a/ir/shared/src/main/scala/org/scalajs/ir/Serializers.scala b/ir/shared/src/main/scala/org/scalajs/ir/Serializers.scala
@@ -1790,7 +1790,7 @@ object Serializers {
 
     val use14: Boolean = use13 || sourceVersion == "1.4"
 
-    val use15: Boolean = true // use14 || sourceVersion == "1.5"
+    val use15: Boolean = use14 || sourceVersion == "1.5"
   }
 
   /** Names needed for hacks. */

Original file line number	Diff line number	Diff line change
`@@ -1790,7 +1790,7 @@ object Serializers {`
`1790`	`1790`
`1791`	`1791`	`val use14: Boolean = use13 \|\| sourceVersion == "1.4"`
`1792`	`1792`
`1793`		`- val use15: Boolean = true // use14 \|\| sourceVersion == "1.5"`
	`1793`	`+ val use15: Boolean = use14 \|\| sourceVersion == "1.5"`
`1794`	`1794`	`}`
`1795`	`1795`
`1796`	`1796`	`/** Names needed for hacks. */`