New ErrorCode(8111) for local functions not having a body

https://github.com/dotnet/roslyn/issues/14900

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

@@ -462,7 +462,7 @@ private BoundStatement BindLocalFunctionStatement(LocalFunctionStatementSyntax n
                 block = null;
                 hasErrors = true;
                 // TODO(https://github.com/dotnet/roslyn/issues/14900): Better error message
-                diagnostics.Add(ErrorCode.ERR_ConcreteMissingBody, localSymbol.Locations[0], localSymbol);
+                diagnostics.Add(ErrorCode.ERR_LocalFunctionMissingBody, localSymbol.Locations[0], localSymbol);
             }
 
             if (block != null)

src/Compilers/CSharp/Portable/CSharpResources.Designer.cs

@@ -5911,6 +5911,15 @@ internal class CSharpResources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; is a local function and must therefore always have a body..
+        /// </summary>
+        internal static string ERR_LocalFunctionMissingBody {
+            get {
+                return ResourceManager.GetString("ERR_LocalFunctionMissingBody", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to A local or parameter named &apos;{0}&apos; cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter.
         /// </summary>

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -5073,4 +5073,7 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ChangingReferencedAssemblyVersionNotAllowed" xml:space="preserve">
     <value>Changing the version of an assembly reference is not allowed during debugging: '{0}' changed version to {1}</value>
   </data>
+  <data name="ERR_LocalFunctionMissingBody" xml:space="preserve">
+    <value>'{0}' is a local function and must therefore always have a body.</value>
+  </data>
 </root>
\ No newline at end of file

src/Compilers/CSharp/Portable/Errors/ErrorCode.cs

@@ -1343,6 +1343,7 @@ internal enum ErrorCode
         #region diagnostics for local functions introduced in C# 7
         ERR_DynamicLocalFunctionParamsParameter = 8108,
         ERR_ExpressionTreeContainsLocalFunction = 8110,
+        ERR_LocalFunctionMissingBody = 8111, //https://github.com/dotnet/roslyn/issues/14900
         #endregion diagnostics for local functions introduced in C# 7
 
         #region diagnostics for instrumentation

src/Compilers/CSharp/Portable/Symbols/ReferenceManager.cs

@@ -286,7 +286,7 @@ private static AssemblySymbol MapAssemblyIdentityToResolvedSymbol(AssemblyIdenti
                 if (map.TryGetValue(identity, out symbol, (v1, v2, s) => true))
                 {
                     // TODO: https://github.com/dotnet/roslyn/issues/9004
-                    throw new NotSupportedException(string.Format(CSharpResources.ChangingReferencedAssemblyVersionNotAllowed, identity, symbol.Identity.Version);
+                    throw new NotSupportedException(string.Format(CSharpResources.ChangingReferencedAssemblyVersionNotAllowed, identity, symbol.Identity.Version));
                 }
 
                 return new MissingAssemblySymbol(identity);