[CodeCompletion] Use getBodySourceRange() instead of getSourceRange()

To check if the completion is happening in the AFD body.
Otherwise, local variables are sometimes not suggested because the body
and its range is from another file.

rdar://problem/58175106
(cherry picked from commit 046c914)

Author: rintaro

lib/Sema/LookupVisibleDecls.cpp

@@ -1089,8 +1089,8 @@ static void lookupVisibleDeclsImpl(VisibleDeclConsumer &Consumer,
       // FIXME: when we can parse and typecheck the function body partially for
       // code completion, AFD->getBody() check can be removed.
       if (Loc.isValid() &&
-          AFD->getSourceRange().isValid() &&
-          SM.rangeContainsTokenLoc(AFD->getSourceRange(), Loc) &&
+          AFD->getBodySourceRange().isValid() &&
+          SM.rangeContainsTokenLoc(AFD->getBodySourceRange(), Loc) &&
           AFD->getBody()) {
         namelookup::FindLocalVal(SM, Loc, Consumer).visit(AFD->getBody());
       }

test/SourceKit/CodeComplete/complete_sequence_localvar.swift

@@ -0,0 +1,26 @@
+func test() {
+  var localVar = 1
+
+  var afterVar = 1
+}
+
+// RUN: %sourcekitd-test \
+// RUN:   -req=complete -req-opts=reuseastcontext=1 -pos=3:1 %s -- %s == \
+// RUN:   -req=complete -req-opts=reuseastcontext=1 -pos=3:1 %s -- %s == \
+// RUN:   -req=complete -req-opts=reuseastcontext=1 -pos=3:1 %s -- %s == \
+// RUN:   -req=complete -req-opts=reuseastcontext=1 -pos=3:1 %s -- %s == \
+// RUN:   -req=complete -req-opts=reuseastcontext=1 -pos=3:1 %s -- %s | %FileCheck %s
+
+// CHECK-NOT: key.name: "localVar"
+// CHECK-NOT: key.name: "afterVar"
+// CHECK: key.name: "localVar"
+// CHECK-NOT: key.name: "afterVar"
+// CHECK: key.name: "localVar"
+// CHECK-NOT: key.name: "afterVar"
+// CHECK: key.name: "localVar"
+// CHECK-NOT: key.name: "afterVar"
+// CHECK: key.name: "localVar"
+// CHECK-NOT: key.name: "afterVar"
+// CHECK: key.name: "localVar"
+// CHECK-NOT: key.name: "localVar"
+// CHECK-NOT: key.name: "afterVar"