From 4f3c7d6703001f920ee702ec96a6c6e214964a44 Mon Sep 17 00:00:00 2001
From: Carol Eidt <carol.eidt@microsoft.com>
Date: Mon, 19 Nov 2018 19:43:03 -0800
Subject: [PATCH] Add asserts for the types of the Span indexers.
 (dotnet/coreclr#21037)

Also, add a test for dotnet/coreclr#20958

Commit migrated from https://github.com/dotnet/coreclr/commit/398c3bc97d5297df9773284a03e425f90c40bcf0
---
 src/coreclr/src/jit/importer.cpp                   |  2 +
 .../JitBlue/GitHub_20958/GitHub_20958.cs           | 61 ++++++++++++++++++++++
 .../JitBlue/GitHub_20958/GitHub_20958.csproj       | 17 ++++++
 3 files changed, 80 insertions(+)
 create mode 100644 src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_20958/GitHub_20958.cs
 create mode 100644 src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_20958/GitHub_20958.csproj

diff --git a/src/coreclr/src/jit/importer.cpp b/src/coreclr/src/jit/importer.cpp
index 6aba974..6062511 100644
--- a/src/coreclr/src/jit/importer.cpp
+++ b/src/coreclr/src/jit/importer.cpp
@@ -3821,6 +3821,8 @@ GenTree* Compiler::impIntrinsic(GenTree*                newobjThis,
             GenTree* ptrToSpan      = impPopStack().val;
             GenTree* indexClone     = nullptr;
             GenTree* ptrToSpanClone = nullptr;
+            assert(varTypeIsIntegral(index));
+            assert(ptrToSpan->TypeGet() == TYP_BYREF);
 
 #if defined(DEBUG)
             if (verbose)
diff --git a/src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_20958/GitHub_20958.cs b/src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_20958/GitHub_20958.cs
new file mode 100644
index 0000000..74ea90e
--- /dev/null
+++ b/src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_20958/GitHub_20958.cs
@@ -0,0 +1,61 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+
+// This test was extracted from the Indexer tests in the corefx System.Memory.Tests.
+// The JIT was trying to expand the form of indexer that takes a range, but was not
+// correctly expanding it, as it was expecting only the scalar index form.
+
+public class GitHub_20958
+{
+
+    public static int IndexerWithRangeTest()
+    {
+        int returnVal = 100;
+   
+        ReadOnlySpan<char> span = "Hello".AsSpan();
+        ReadOnlySpan<char> sliced = span[Range.Create(new Index(1, fromEnd: false), new Index(1, fromEnd: true))];
+        if (span.Slice(1, 3) != sliced)
+        {
+            returnVal = -1;
+        }
+        try
+        {
+            ReadOnlySpan<char> s = "Hello".AsSpan()[Range.Create(new Index(1, fromEnd: true), new Index(1, fromEnd: false))];
+            returnVal = -1;
+        }
+        catch (ArgumentOutOfRangeException)
+        {
+        }
+        catch (Exception e)
+        {
+            returnVal = -1;
+        }
+        Span<char> span1 = new Span<char>(new char[] { 'H', 'e', 'l', 'l', 'o' });
+        Span<char> sliced1 = span1[Range.Create(new Index(2, fromEnd: false), new Index(1, fromEnd: true))];
+        if (span1.Slice(2, 2) != sliced1)
+        {
+            returnVal = -1;
+        }
+        try
+        {
+            Span<char> s = new Span<char>(new char[] { 'H', 'i' })[Range.Create(new Index(0, fromEnd: true), new Index(1, fromEnd: false))];
+            returnVal = -1;
+        }
+        catch (ArgumentOutOfRangeException)
+        {
+        }
+        catch (Exception e)
+        {
+            returnVal = -1;
+        }
+        return returnVal;
+    }
+
+    public static int Main()
+    {
+        return IndexerWithRangeTest();
+    }
+}
diff --git a/src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_20958/GitHub_20958.csproj b/src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_20958/GitHub_20958.csproj
new file mode 100644
index 0000000..d86ed9f
--- /dev/null
+++ b/src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_20958/GitHub_20958.csproj
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Release</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <AssemblyName>$(MSBuildProjectName)</AssemblyName>
+    <OutputType>Exe</OutputType>
+    <DebugType></DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+  <PropertyGroup Condition=" '$(MsBuildProjectDirOverride)' != '' "></PropertyGroup>
+</Project>
\ No newline at end of file
-- 
2.7.4