4 files changed, 63 insertions, 0 deletions
diff --git a/test/files/neg/t8675.check b/test/files/neg/t8675.check
new file mode 100644
index 0000000000..4e44fba918
--- /dev/null
+++ b/test/files/neg/t8675.check
@@ -0,0 +1,11 @@
+t8675.scala:13: error: type mismatch;
+ found   : Boolean(true)
+ required: String
+    a.update(0, x[A]({new isString(true)})) // !!! allowed
+                                   ^
+t8675.scala:22: error: type mismatch;
+ found   : Boolean(true)
+ required: String
+    new X().m(x[A]({new isString(true)})) // !!! allowed
+                                 ^
+two errors found
diff --git a/test/files/neg/t8675.scala b/test/files/neg/t8675.scala
new file mode 100644
index 0000000000..ca9bb57ffa
--- /dev/null
+++ b/test/files/neg/t8675.scala
@@ -0,0 +1,24 @@
+class A(s: String) {
+  def foo(x: A) = x
+}
+
+class isString(s: String)
+
+class Test {
+
+  def x[A](a: Any): A = ???
+
+  def test {
+    val a = Array[A]()
+    a.update(0, x[A]({new isString(true)})) // !!! allowed
+
+    // boils down to
+    class X {
+      def m(p: Any) {}
+    }
+    implicit class XOps(x: X) {
+      def m(p: Any) {}
+    }
+    new X().m(x[A]({new isString(true)})) // !!! allowed
+  }
+}
diff --git a/test/files/neg/t8675b.check b/test/files/neg/t8675b.check
new file mode 100644
index 0000000000..cb7ac8af59
--- /dev/null
+++ b/test/files/neg/t8675b.check
@@ -0,0 +1,6 @@
+t8675b.scala:19: error: missing parameter type for expanded function
+The argument types of an anonymous function must be fully known. (SLS 8.5)
+Expected type was: List[Test.Reportable1[?,?]] => Boolean
+  for (path: List[Any] <- (null : Engine1).asRequirement.pathsIncludingSelf.toList) {
+                                                                            ^
+one error found
diff --git a/test/files/neg/t8675b.scala b/test/files/neg/t8675b.scala
new file mode 100644
index 0000000000..2c5015b1d0
--- /dev/null
+++ b/test/files/neg/t8675b.scala
@@ -0,0 +1,22 @@
+object Test {
+  trait Engine1
+
+  implicit class EngineTools1[Params, R](e: Engine1) {
+    def asRequirement: Requirement1[Params, R] = ???
+  }
+  trait Requirement1[Params, R] {
+    def pathsIncludingSelf: Traversable[List[Reportable1[Params, R]]]
+  }
+  trait Reportable1[Params, R]
+
+  // "missing paramater type" error was swallowed in 2.11.0 leading to a crash
+  // in the backend.
+  //
+  // This error is itself a regression (or at least a change) in 2.11.0-M7,
+  // specifically in SI-7944. The type paramaters to the implicit view
+  // `EngineTools1` are undetermined, and are now treated as type variables
+  // in the expected type of the closure argument to `withFilter`.
+  for (path: List[Any] <- (null : Engine1).asRequirement.pathsIncludingSelf.toList) {
+    ???
+  }
+}