[CodeCompletion] Fix completion in repeat statements

Improve the error recovery so that we get back either a RepeatWhileStmt,
or at least a BraceStmt, which code-completion can use to dig out the
local variables.

rdar://problem/25912182

Author: benlangmuir

lib/Parse/ParseStmt.cpp

@@ -1949,8 +1949,6 @@ ParserResult<Stmt> Parser::parseStmtRepeat(LabeledStmtInfo labelInfo) {
   ParserResult<BraceStmt> body =
       parseBraceItemList(diag::expected_lbrace_after_repeat);
   status |= body;
-  if (status.hasCodeCompletion())
-    return makeParserResult<Stmt>(status, nullptr);
   if (body.isNull())
     body = makeParserResult(
         body, BraceStmt::create(Context, repeatLoc, {}, PreviousLoc, true));
@@ -1972,7 +1970,7 @@ ParserResult<Stmt> Parser::parseStmtRepeat(LabeledStmtInfo labelInfo) {
     condition = parseExpr(diag::expected_expr_repeat_while);
     status |= condition;
     if (condition.isNull()) {
-      return makeParserResult<Stmt>(status, nullptr); // FIXME: better recovery
+      condition = makeParserErrorResult(new (Context) ErrorExpr(whileLoc));
     }
   }
 

test/IDE/complete_repeat.swift

@@ -0,0 +1,71 @@
+// RUN: %swift-ide-test -code-completion -code-completion-token=REPEAT_1 -source-filename=%s | FileCheck %s -check-prefix=REPEAT_1
+// RUN: %swift-ide-test -code-completion -code-completion-token=REPEAT_2 -source-filename=%s | FileCheck %s -check-prefix=REPEAT_2
+// RUN: %swift-ide-test -code-completion -code-completion-token=REPEAT_3 -source-filename=%s | FileCheck %s -check-prefix=REPEAT_3
+// RUN: %swift-ide-test -code-completion -code-completion-token=REPEAT_4 -source-filename=%s | FileCheck %s -check-prefix=REPEAT_4
+// RUN: %swift-ide-test -code-completion -code-completion-token=REPEAT_5 -source-filename=%s | FileCheck %s -check-prefix=REPEAT_5
+// RUN: %swift-ide-test -code-completion -code-completion-token=REPEAT_COND_1 -source-filename=%s | FileCheck %s -check-prefix=REPEAT_COND_1
+
+repeat {
+  let local1 = 1
+  #^REPEAT_1^#
+} while true
+// REPEAT_1-NOT: LocalVar
+// REPEAT_1: Decl[LocalVar]/Local:               local1[#Int#];
+// REPEAT_1-NOT: LocalVar
+
+repeat {
+  let local1 = 1
+  #^REPEAT_2^#
+}
+// REPEAT_2-NOT: LocalVar
+// REPEAT_2: Decl[LocalVar]/Local:               local1[#Int#];
+// REPEAT_2-NOT: LocalVar
+
+repeat {
+  let local1 = 1
+  repeat {
+    let local2 = 1
+    #^REPEAT_3^#
+  } while true
+} while true
+// REPEAT_3-NOT: LocalVar
+// REPEAT_3: Decl[LocalVar]/Local:               local2[#Int#];
+// REPEAT_3-NOT: LocalVar
+// REPEAT_3: Decl[LocalVar]/Local:               local1[#Int#];
+// REPEAT_3-NOT: LocalVar
+
+func enclosingFunc1() {
+  let local0 = 1
+  repeat {
+    let local1 = 1
+    repeat {
+      let local2 = 1
+      #^REPEAT_4^#
+    } while true
+  } while true
+}
+// REPEAT_4-NOT: LocalVar
+// REPEAT_4: Decl[LocalVar]/Local:               local2[#Int#];
+// REPEAT_4-NOT: LocalVar
+// REPEAT_4: Decl[LocalVar]/Local:               local1[#Int#];
+// REPEAT_4-NOT: LocalVar
+// REPEAT_4: Decl[LocalVar]/Local:               local0[#Int#];
+// REPEAT_4-NOT: LocalVar
+
+repeat {
+  let local1 = 1
+  #^REPEAT_5^#
+} while
+// REPEAT_5-NOT: LocalVar
+// REPEAT_5: Decl[LocalVar]/Local:               local1[#Int#];
+// REPEAT_5-NOT: LocalVar
+
+repeat {
+  let local1 = 1
+  repeat {
+    let local2 = 1
+  } while #^REPEAT_COND_1^#
+}
+// REPEAT_COND_1-NOT: LocalVar
+// REPEAT_COND_1: Decl[LocalVar]/Local:               local1[#Int#];
+// REPEAT_COND_1-NOT: LocalVar