Fix leak checking

odersky · odersky · commit cd74cac72d0e · 2019-07-01T19:07:38.000+02:00
When compiling Parsers.scala with mismatched braces, I saw

```
java.lang.AssertionError: assertion failed: leak: &lt;error no implicit values were found that match type dotty.tools.dotc.core.Contexts.Context&gt;
[error]   (
[error] vdef) in ...
```
The issue is here that we should disregard leaks with erroneous types.
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -715,7 +715,7 @@ class Typer extends Namer
 
   def escapingRefs(block: Tree, localSyms: => List[Symbol])(implicit ctx: Context): collection.Set[NamedType] = {
     lazy val locals = localSyms.toSet
-    block.tpe namedPartsWith (tp => locals.contains(tp.symbol))
+    block.tpe.namedPartsWith(tp => locals.contains(tp.symbol) && !tp.widen.isErroneous)
   }
 
   /** Ensure that an expression's type can be expressed without references to locally defined

Original file line number	Diff line number	Diff line change
`@@ -715,7 +715,7 @@ class Typer extends Namer`
`715`	`715`
`716`	`716`	`def escapingRefs(block: Tree, localSyms: => List[Symbol])(implicit ctx: Context): collection.Set[NamedType] = {`
`717`	`717`	`lazy val locals = localSyms.toSet`
`718`		`- block.tpe namedPartsWith (tp => locals.contains(tp.symbol))`
	`718`	`+ block.tpe.namedPartsWith(tp => locals.contains(tp.symbol) && !tp.widen.isErroneous)`
`719`	`719`	`}`
`720`	`720`
`721`	`721`	`/** Ensure that an expression's type can be expressed without references to locally defined`