[nomaster] 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
(cherry picked from commit 3028327e2a2b553b12ee45519413515c8aa0865f)

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..1d84abd617
--- /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
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo()test.Foo`
+[accessible:  true] `method fCCC=> Int`
+[accessible:  true] `method fOOO=> Int`
+[accessible:  true] `object Otest.O.type`
+[accessible:  true] `value otest.O.type`
+================================================================================
+
+askScopeCompletion at Completions.scala(19,4)
+================================================================================
+[response] askScopeCompletion at (19,4)
+retrieved 9 members
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo()test.Foo`
+[accessible:  true] `method fCCC=> Int`
+[accessible:  true] `method fOOO=> Int`
+[accessible:  true] `object Otest.O.type`
+================================================================================
+
+askScopeCompletion at Completions.scala(24,4)
+================================================================================
+[response] askScopeCompletion at (24,4)
+retrieved 9 members
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo()test.Foo`
+[accessible:  true] `method fCCC=> Int`
+[accessible:  true] `object Otest.O.type`
+[accessible:  true] `value ctest.C`
+================================================================================
+
+askScopeCompletion at Completions.scala(27,5)
+================================================================================
+[response] askScopeCompletion at (27,5)
+retrieved 8 members
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo()test.Foo`
+[accessible:  true] `object Otest.O.type`
+[accessible:  true] `value ctest.C`
+================================================================================
+
+askScopeCompletion at Completions.scala(30,5)
+================================================================================
+[response] askScopeCompletion at (30,5)
+retrieved 9 members
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo()test.Foo`
+[accessible:  true] `method fCCC=> Int`
+[accessible:  true] `object Otest.O.type`
+[accessible:  true] `value ctest.C`
+================================================================================
+
+askScopeCompletion at Completions.scala(32,5)
+================================================================================
+[response] askScopeCompletion at (32,5)
+retrieved 10 members
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo()test.Foo`
+[accessible:  true] `method fCCC=> Int`
+[accessible:  true] `method fOOO=> Int`
+[accessible:  true] `object Otest.O.type`
+[accessible:  true] `value ctest.C`
+================================================================================
+
+askScopeCompletion at Completions.scala(41,4)
+================================================================================
+[response] askScopeCompletion at (41,4)
+retrieved 10 members
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo_1()test.Foo_1`
+[accessible:  true] `method bar=> Unit`
+[accessible:  true] `method fCCC=> Int`
+[accessible:  true] `method fOOO=> Int`
+[accessible:  true] `object Otest.O.type`
+================================================================================
+
+askScopeCompletion at Completions.scala(51,4)
+================================================================================
+[response] askScopeCompletion at (51,4)
+retrieved 11 members
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo_2()test.Foo_2`
+[accessible:  true] `method bar=> Unit`
+[accessible:  true] `method fCCC=> Int`
+[accessible:  true] `method fOOO=> Int`
+[accessible:  true] `object Otest.O.type`
+[accessible:  true] `value otest.O.type`
+================================================================================
+
+askScopeCompletion at Completions.scala(61,4)
+================================================================================
+[response] askScopeCompletion at (61,4)
+retrieved 10 members
+[accessible:  true] `class Ctest.C`
+[accessible:  true] `class Foo_1test.Foo_1`
+[accessible:  true] `class Foo_2test.Foo_2`
+[accessible:  true] `class Foo_3test.Foo_3`
+[accessible:  true] `class Footest.Foo`
+[accessible:  true] `constructor Foo_3()test.Foo_3`
+[accessible:  true] `method bar=> Unit`
+[accessible:  true] `method fCCC=> Int`
+[accessible:  true] `object Otest.O.type`
+[accessible:  true] `value ctest.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 {
+    /*_*/
+  }
+}
+