From abd5ab8080afe40e4ecab4b66c19b4cbf1cf5e0b Mon Sep 17 00:00:00 2001
From: "N. Taylor Mullen" <nimullen@microsoft.com>
Date: Thu, 7 Feb 2019 09:47:42 -0800
Subject: [PATCH] Add @await foreach for C# 8

- Added general C# 8 tests that we can use to include nullability when the time comes.
- Added statement test to ensure syntax tree is correct for await foreach.

aspnet/AspNetCoredotnet/aspnetcore-tooling#5078
\n\nCommit migrated from https://github.com/dotnet/aspnetcore-tooling/commit/27e1d8c0113034b85d7f8443403d9737d21c1c82
---
 .../src/Legacy/CSharpCodeParser.cs                  | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Legacy/CSharpCodeParser.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Legacy/CSharpCodeParser.cs
index b9dc3bc9d2..e0fc7790c1 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Legacy/CSharpCodeParser.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Legacy/CSharpCodeParser.cs
@@ -1651,7 +1651,18 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
             // Therefore, if we're top level then we want to act like an implicit expression,
             // otherwise just act as whatever we're contained in.
             var topLevel = transition != null;
-            if (topLevel)
+            if (!topLevel)
+            {
+                return;
+            }
+
+            if (At(CSharpKeyword.Foreach))
+            {
+                // C# 8 async streams. @await foreach (var value in asyncEnumerable) { .... }
+
+                ParseConditionalBlock(builder, transition);
+            }
+            else
             {
                 // Setup the Span to be an async implicit expression (an implicit expresison that allows spaces).
                 // Spaces are allowed because of "@await Foo()".