SI-7280 Scope completion not returning members provided by imports

Updates localeContext() to return the best context possible when there are none directly
associated with the given position. It happens when an expression cannot be
successfully typed, as no precise ContextTree covers the expression location, or if the
position is not inside any expression.
Adds corresponding tests

3 files changed, 208 insertions, 0 deletions

diff --git a/test/files/presentation/scope-completion-import.check b/test/files/presentation/scope-completion-import.check
new file mode 100644
index 0000000000..d518b0c37a
--- /dev/null
+++ b/test/files/presentation/scope-completion-import.check
@@ -0,0 +1,141 @@
+reload: Completions.scala
+
+askScopeCompletion at Completions.scala(15,4)
+================================================================================
+[response] askScopeCompletion at (15,4)
+retrieved 10 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo
+def fCCC: Int
+def fOOO: Int
+object O
+val o: test.O.type
+================================================================================
+
+askScopeCompletion at Completions.scala(19,4)
+================================================================================
+[response] askScopeCompletion at (19,4)
+retrieved 9 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo
+def fCCC: Int
+def fOOO: Int
+object O
+================================================================================
+
+askScopeCompletion at Completions.scala(24,4)
+================================================================================
+[response] askScopeCompletion at (24,4)
+retrieved 9 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo
+def fCCC: Int
+object O
+val c: test.C
+================================================================================
+
+askScopeCompletion at Completions.scala(27,5)
+================================================================================
+[response] askScopeCompletion at (27,5)
+retrieved 8 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo
+object O
+val c: test.C
+================================================================================
+
+askScopeCompletion at Completions.scala(30,5)
+================================================================================
+[response] askScopeCompletion at (30,5)
+retrieved 9 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo
+def fCCC: Int
+object O
+val c: test.C
+================================================================================
+
+askScopeCompletion at Completions.scala(32,5)
+================================================================================
+[response] askScopeCompletion at (32,5)
+retrieved 10 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo
+def fCCC: Int
+def fOOO: Int
+object O
+val c: test.C
+================================================================================
+
+askScopeCompletion at Completions.scala(41,4)
+================================================================================
+[response] askScopeCompletion at (41,4)
+retrieved 10 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo_1
+def bar: Unit
+def fCCC: Int
+def fOOO: Int
+object O
+================================================================================
+
+askScopeCompletion at Completions.scala(51,4)
+================================================================================
+[response] askScopeCompletion at (51,4)
+retrieved 11 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo_2
+def bar: Unit
+def fCCC: Int
+def fOOO: Int
+object O
+private[this] val o: test.O.type
+================================================================================
+
+askScopeCompletion at Completions.scala(61,4)
+================================================================================
+[response] askScopeCompletion at (61,4)
+retrieved 10 members
+class C extends AnyRef
+class Foo extends AnyRef
+class Foo_1 extends AnyRef
+class Foo_2 extends AnyRef
+class Foo_3 extends AnyRef
+def <init>(): test.Foo_3
+def bar: Unit
+def fCCC: Int
+object O
+private[this] val c: test.C
+================================================================================
diff --git a/test/files/presentation/scope-completion-import/Test.scala b/test/files/presentation/scope-completion-import/Test.scala
new file mode 100644
index 0000000000..bec1131c4c
--- /dev/null
+++ b/test/files/presentation/scope-completion-import/Test.scala
@@ -0,0 +1,3 @@
+import scala.tools.nsc.interactive.tests.InteractiveTest
+
+object Test extends InteractiveTest
\ No newline at end of file
diff --git a/test/files/presentation/scope-completion-import/src/Completions.scala b/test/files/presentation/scope-completion-import/src/Completions.scala
new file mode 100644
index 0000000000..6e08321283
--- /dev/null
+++ b/test/files/presentation/scope-completion-import/src/Completions.scala
@@ -0,0 +1,64 @@
+package test
+
+class C {
+  def fCCC : Int = 0
+}
+
+object O extends C {
+  def fOOO : Int = 0
+}
+
+class Foo {
+  {
+    val o = O
+    import o._
+    /*_*/
+  }
+  {
+    import O._
+    /*_*/
+  }
+  {
+    val c = new C
+    import c._
+    /*_*/
+  }
+  {
+    f/*_*/
+    val c = new C
+    import c._
+    f/*_*/
+    import O._
+    f/*_*/
+  }
+}
+
+class Foo_1 {
+
+  import O._
+
+  def bar {
+    /*_*/
+  }
+}
+
+class Foo_2 {
+
+  val o = O
+  import o._
+
+  def bar {
+    /*_*/
+  }
+}
+
+class Foo_3 {
+
+  val c = new C
+  import c._
+
+  def bar {
+    /*_*/
+  }
+}
+