SI-6863 Fix verify error in captured var inited from expr with try/catch

If a captured var was inited from a try/catch we did something
reasonable. But if the var was inited from a more complicated expression
(if/else, a block, match/case, etc) that ended with
a try/catch then we didn't and we were generating faulty byte code.
This fix patches LambdaLift to add the missing cases.

For known simple expressions, the translation is just new *Ref(expr).

For try/catch, if/else, match/case, and blocks this recursively
walks down the internal result expressions to translate them. E.g.
if(cond) trueExpr else falseExpr becomes if(cone) translate(trueExpr)
else translate(falseExpr)

For unknown expression types, the translation is {val temp = expr; new
  *Ref(expr) }

1 files changed, 114 insertions, 0 deletions

diff --git a/test/files/run/t6863.scala b/test/files/run/t6863.scala
new file mode 100644
index 0000000000..d77adb6af4
--- /dev/null
+++ b/test/files/run/t6863.scala
@@ -0,0 +1,114 @@
+/** Make sure that when a variable is captured its initialization expression is handled properly */
+object Test {
+  def lazyVal() = {
+  	// internally lazy vals become vars which are initialized with "_", so they need to be tested just like vars do
+  	lazy val x = "42"
+    assert({ () => x }.apply == "42")    
+  }
+  def ident() = {
+    val y = "42"
+    var x = y
+    assert({ () => x }.apply == "42")    
+  }
+  def apply() = {
+    def y(x : Int) = x.toString
+    var x = y(42)
+    assert({ () => x }.apply == "42")        
+  }
+  def literal() = {
+    var x = "42"
+    assert({ () => x }.apply == "42")    
+  }
+  def `new`() = {
+    var x = new String("42")
+    assert({ () => x }.apply == "42")            
+  }
+  def select() = {
+    object Foo{val bar = "42"}
+    var x = Foo.bar
+    assert({ () => x }.apply == "42")            
+  }
+  def `throw`() = {
+    var x = if (true) "42" else throw new Exception("42")
+    assert({ () => x }.apply == "42")            
+  }
+  def assign() = {
+    var y = 1
+    var x = y = 42
+    assert({ () => x}.apply == ())
+  }
+  def valDef() = {
+    var x = {val y = 42}
+    assert({ () => x}.apply == ())
+  }
+  def `return`(): String = {
+    var x = if (true) return "42" else ()
+    assert({ () => x}.apply == ())
+    "42"
+  }
+  def tryFinally() = {
+    var x = try { "42" } finally ()
+    assert({ () => x }.apply == "42")
+  }
+  def tryCatch() = {
+    var x = try { "42" } catch { case _ => "43" }
+    assert({ () => x }.apply == "42")
+  }
+  def `if`() = {
+  	var x = if (true) ()
+    assert({ () => x }.apply == ())
+  }
+  def ifElse() = {
+    var x = if(true) "42" else "43" 
+    assert({ () => x }.apply == "42")
+  }
+  def matchCase() = {
+    var x = 100 match {
+       case 100 => "42"
+      case _ => "43"
+    }
+    assert({ () => x }.apply == "42")
+  }
+  def block() = {
+    var x = {
+      val y = 42
+      "42"
+    }
+    assert({ () => x }.apply == "42")
+  }
+  def labelDef() = {
+    var x = 100 match { 
+      case 100 => try "42" finally ()
+    }
+    assert({ () => x }.apply == "42")
+  }
+  def nested() = {
+    var x = {
+      val y = 42
+        if(true) try "42" catch {case _ => "43"}
+        else "44"       
+    }
+    assert({ () => x }.apply == "42")
+  }
+  def main(args: Array[String]) {
+  	lazyVal()
+    ident()
+    apply()
+    literal()
+    `new`()
+    select()
+    `throw`()
+    assign()
+    valDef()
+    `return`()
+    tryFinally()
+    tryCatch()
+    ifElse()
+    `if`()
+    matchCase()
+    block()
+    labelDef()
+    nested()
+  }
+}
+