Typer should leave inline exception handlers inline.

Author: DarkDimius

src/dotty/tools/dotc/typer/Typer.scala

@@ -663,7 +663,13 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
 
   def typedTry(tree: untpd.Try, pt: Type)(implicit ctx: Context): Try = track("typedTry") {
     val expr1 = typed(tree.expr, pt)
-    val handler1 = typed(tree.handler, defn.FunctionType(defn.ThrowableType :: Nil, pt))
+    val handler1: Tree = tree.handler match {
+      case h: untpd.Match if ((h.selector eq EmptyTree)                   // comes from parser
+                               || (h.selector eq ExceptionHandlerSel)) => // during retyping
+        val cases1 = typedCases(h.cases, defn.ThrowableType, pt)
+        assignType(untpd.Match(ExceptionHandlerSel, cases1), cases1)
+      case _ => typed(tree.handler, defn.FunctionType(defn.ThrowableType :: Nil, pt))
+    }
     val finalizer1 = typed(tree.finalizer, defn.UnitType)
     assignType(cpy.Try(tree)(expr1, handler1, finalizer1), expr1, handler1)
   }

tests/pos/tryTyping.scala

@@ -7,8 +7,14 @@ object tryTyping{
   }
 
   def foo2: Int = {
-    val a: (Throwable => Int) = _ match {case _ => 2}
+    val a2: (Throwable => Int) = _ match {case _ => 2}
     try{???; 1}
-    catch a
+    catch a2
+  }
+
+  def foo3: Int = {
+    val a3: (Int => Throwable => Int) = (b: Int) => _ match {case _ => b}
+    try{???; 1}
+    catch a3(3)
   }
 }