Fix #4240: Deprecate nonlocal returns 🔥

OlivierBlanvillain · OlivierBlanvillain · commit 4c813c123f4d · 2019-06-07T11:16:18.000+02:00
diff --git a/compiler/src/dotty/tools/dotc/transform/NonLocalReturns.scala b/compiler/src/dotty/tools/dotc/transform/NonLocalReturns.scala
@@ -86,6 +86,9 @@ class NonLocalReturns extends MiniPhase {
     }
 
   override def transformReturn(tree: Return)(implicit ctx: Context): Tree =
-    if (isNonLocalReturn(tree)) nonLocalReturnThrow(tree.expr, tree.from.symbol).withSpan(tree.span)
-    else tree
+    if (isNonLocalReturn(tree)) {
+      if (!ctx.scala2Mode)
+        ctx.strictWarning("Non local returns are deprecated; use scala.util.control.NonLocalReturns instead", tree.sourcePos)
+      nonLocalReturnThrow(tree.expr, tree.from.symbol).withSpan(tree.span)
+    } else tree
 }

Original file line number	Diff line number	Diff line change
`@@ -86,6 +86,9 @@ class NonLocalReturns extends MiniPhase {`
`86`	`86`	`}`
`87`	`87`
`88`	`88`	`override def transformReturn(tree: Return)(implicit ctx: Context): Tree =`
`89`		`- if (isNonLocalReturn(tree)) nonLocalReturnThrow(tree.expr, tree.from.symbol).withSpan(tree.span)`
`90`		`- else tree`
	`89`	`+ if (isNonLocalReturn(tree)) {`
	`90`	`+ if (!ctx.scala2Mode)`
	`91`	`+ ctx.strictWarning("Non local returns are deprecated; use scala.util.control.NonLocalReturns instead", tree.sourcePos)`
	`92`	`+ nonLocalReturnThrow(tree.expr, tree.from.symbol).withSpan(tree.span)`
	`93`	`+ } else tree`
`91`	`94`	`}`