Merge pull request #11256 from khyperia/fix10463

Generalize dynamic static-only restriction to include field initializers

src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs

@@ -270,11 +270,13 @@ private BoundExpression BindArgListOperator(InvocationExpressionSyntax node, Dia
                             break;
 
                         case BoundKind.ThisReference:
-                            if (InConstructorInitializer && receiver.WasCompilerGenerated)
+                            // Can't call the HasThis method due to EE doing odd things with containing member and its containing type.
+                            if ((InConstructorInitializer || InFieldInitializer) && receiver.WasCompilerGenerated)
                             {
                                 // Only a static method can be called in a constructor initializer. If we were not in a ctor initializer
                                 // the runtime binder would ignore the receiver, but in a ctor initializer we can't read "this" before 
                                 // the base constructor is called. We need to handle this as a type qualified static method call.
+                                // Also applicable to things like field initializers, which run before the ctor initializer.
                                 expression = methodGroup.Update(
                                     methodGroup.TypeArgumentsOpt,
                                     methodGroup.Name,

src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenTests.cs

@@ -14833,6 +14833,73 @@ .maxstack  4
   IL_007f:  callvirt   ""int System.Collections.Generic.List<Program.TextSpan>.Count.get""
   IL_0084:  blt.s      IL_002d
   IL_0086:  ret
+}");
+        }
+
+        [WorkItem(10463, "https://github.com/dotnet/roslyn/issues/10463")]
+        [Fact]
+        public void FieldInitializerDynamic()
+        {
+            string source = @"
+using System;
+
+class M
+{
+    object a = Test((dynamic)2);
+
+    static object Test(object obj) => obj;
+
+    static void Main()
+    {
+        Console.Write(new M().a);
+    }
+}
+";
+
+            var compilation = CompileAndVerify(source, new[] { SystemCoreRef, CSharpRef }, expectedOutput: "2");
+
+            // the main point of this test is to have it PEVerify/run correctly, although checking IL too can't hurt.
+            compilation.VerifyIL("M..ctor",
+@"{
+  // Code size      115 (0x73)
+  .maxstack  10
+  IL_0000:  ldarg.0
+  IL_0001:  ldsfld     ""System.Runtime.CompilerServices.CallSite<System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic>> M.<>o__3.<>p__0""
+  IL_0006:  brtrue.s   IL_0043
+  IL_0008:  ldc.i4.0
+  IL_0009:  ldstr      ""Test""
+  IL_000e:  ldnull
+  IL_000f:  ldtoken    ""M""
+  IL_0014:  call       ""System.Type System.Type.GetTypeFromHandle(System.RuntimeTypeHandle)""
+  IL_0019:  ldc.i4.2
+  IL_001a:  newarr     ""Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo""
+  IL_001f:  dup
+  IL_0020:  ldc.i4.0
+  IL_0021:  ldc.i4.s   33
+  IL_0023:  ldnull
+  IL_0024:  call       ""Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo.Create(Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfoFlags, string)""
+  IL_0029:  stelem.ref
+  IL_002a:  dup
+  IL_002b:  ldc.i4.1
+  IL_002c:  ldc.i4.0
+  IL_002d:  ldnull
+  IL_002e:  call       ""Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo.Create(Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfoFlags, string)""
+  IL_0033:  stelem.ref
+  IL_0034:  call       ""System.Runtime.CompilerServices.CallSiteBinder Microsoft.CSharp.RuntimeBinder.Binder.InvokeMember(Microsoft.CSharp.RuntimeBinder.CSharpBinderFlags, string, System.Collections.Generic.IEnumerable<System.Type>, System.Type, System.Collections.Generic.IEnumerable<Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo>)""
+  IL_0039:  call       ""System.Runtime.CompilerServices.CallSite<System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic>> System.Runtime.CompilerServices.CallSite<System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic>>.Create(System.Runtime.CompilerServices.CallSiteBinder)""
+  IL_003e:  stsfld     ""System.Runtime.CompilerServices.CallSite<System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic>> M.<>o__3.<>p__0""
+  IL_0043:  ldsfld     ""System.Runtime.CompilerServices.CallSite<System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic>> M.<>o__3.<>p__0""
+  IL_0048:  ldfld      ""System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic> System.Runtime.CompilerServices.CallSite<System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic>>.Target""
+  IL_004d:  ldsfld     ""System.Runtime.CompilerServices.CallSite<System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic>> M.<>o__3.<>p__0""
+  IL_0052:  ldtoken    ""M""
+  IL_0057:  call       ""System.Type System.Type.GetTypeFromHandle(System.RuntimeTypeHandle)""
+  IL_005c:  ldc.i4.2
+  IL_005d:  box        ""int""
+  IL_0062:  callvirt   ""dynamic System.Func<System.Runtime.CompilerServices.CallSite, System.Type, dynamic, dynamic>.Invoke(System.Runtime.CompilerServices.CallSite, System.Type, dynamic)""
+  IL_0067:  stfld      ""object M.a""
+  IL_006c:  ldarg.0
+  IL_006d:  call       ""object..ctor()""
+  IL_0072:  ret
 }");
         }
     }