Reapply "[CodeCompletion] Don't show the loop index before it is visible"

With the tests updated to account for not having the correct behaviour
for brace-stmt items from after the code-completion point.  That part
turns out to be harder to fix.

This reverts commit a5325e6.

Author: benlangmuir

lib/AST/NameLookupImpl.h

@@ -188,7 +188,8 @@ class FindLocalVal : public StmtVisitor<FindLocalVal> {
     if (!isReferencePointInRange(S->getSourceRange()))
       return;
     visit(S->getBody());
-    checkPattern(S->getPattern(), DeclVisibilityKind::LocalVariable);
+    if (!isReferencePointInRange(S->getSequence()->getSourceRange()))
+      checkPattern(S->getPattern(), DeclVisibilityKind::LocalVariable);
   }
 
   void visitBraceStmt(BraceStmt *S, bool isTopLevelCode = false) {

lib/Parse/ParseStmt.cpp

@@ -2463,8 +2463,6 @@ ParserResult<Stmt> Parser::parseStmtForEach(SourceLoc ForLoc,
   ParserResult<Expr> Where;
   if (consumeIf(tok::kw_where)) {
     Where = parseExprBasic(diag::expected_foreach_where_expr);
-    if (Where.hasCodeCompletion())
-      return makeParserCodeCompletionResult<Stmt>();
     if (Where.isNull())
       Where = makeParserErrorResult(new (Context) ErrorExpr(Tok.getLoc()));
     Status |= Where;

test/IDE/complete_expr_postfix_begin.swift

@@ -57,6 +57,11 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=GENERIC_TYPEALIAS_1 | FileCheck %s -check-prefix=MY_ALIAS
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=GENERIC_TYPEALIAS_2 | FileCheck %s -check-prefix=MY_ALIAS
 
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IN_FOR_EACH_1 | FileCheck %s -check-prefix=IN_FOR_EACH_1
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IN_FOR_EACH_2 | FileCheck %s -check-prefix=IN_FOR_EACH_1
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IN_FOR_EACH_3 | FileCheck %s -check-prefix=IN_FOR_EACH_3
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IN_FOR_EACH_4 | FileCheck %s -check-prefix=IN_FOR_EACH_3
+
 //
 // Test code completion at the beginning of expr-postfix.
 //
@@ -407,3 +412,46 @@ func testGenericTypealias2() {
   var y: MyAlias<Int>
   y = #^GENERIC_TYPEALIAS_2^#
 }
+
+func testInForEach1(arg: Int) {
+  let local = 2
+  for index in #^IN_FOR_EACH_1^# {
+    let inBody = 3
+  }
+  let after = 4
+// IN_FOR_EACH_1-NOT: Decl[LocalVar]
+// IN_FOR_EACH_1: Decl[LocalVar]/Local:               local[#Int#];
+// FIXME: shouldn't show 'after' here.
+// IN_FOR_EACH_1: Decl[LocalVar]/Local:               after[#Int#];
+// IN_FOR_EACH_1: Decl[LocalVar]/Local:               arg[#Int#];
+// IN_FOR_EACH_1-NOT: Decl[LocalVar]
+}
+func testInForEach2(arg: Int) {
+  let local = 2
+  for index in 1 ... #^IN_FOR_EACH_2^# {
+    let inBody = 3
+  }
+  let after = 4
+}
+func testInForEach3(arg: Int) {
+  let local = 2
+  for index: Int in 1 ... 2 where #^IN_FOR_EACH_3^# {
+    let inBody = 3
+  }
+  let after = 4
+// IN_FOR_EACH_3-NOT: Decl[LocalVar]
+// IN_FOR_EACH_3: Decl[LocalVar]/Local:               index[#Int#];
+// IN_FOR_EACH_3-NOT: Decl[LocalVar]
+// IN_FOR_EACH_3: Decl[LocalVar]/Local:               local[#Int#];
+// FIXME: shouldn't show 'after' here.
+// IN_FOR_EACH_3: Decl[LocalVar]/Local:               after[#Int#];
+// IN_FOR_EACH_3: Decl[LocalVar]/Local:               arg[#Int#];
+// IN_FOR_EACH_3-NOT: Decl[LocalVar]
+}
+func testInForEach4(arg: Int) {
+  let local = 2
+  for index in 1 ... 2 {
+    #^IN_FOR_EACH_4^#
+  }
+  let after = 4
+}