[mcs] C#7 throw expression

mcs/errors/cs0019-72.cs

@@ -0,0 +1,10 @@
+// CS0019: Operator `??' cannot be applied to operands of type `void' and `throw expression'
+// Line: 20
+
+class C
+{
+	public static void Main ()
+	{
+		var s = Main () ?? throw null;
+	}
+}

mcs/errors/cs0155-5.cs

@@ -0,0 +1,7 @@
+// CS0155: The type caught or thrown must be derived from System.Exception
+// Line: 9
+
+class X
+{
+    public int Test () => throw "";
+}

mcs/errors/cs0162-21.cs

@@ -0,0 +1,19 @@
+// CS0162: Unreachable code detected
+// Line: 12
+// Compiler options: -warnaserror -warn:2
+
+using System;
+
+class X
+{
+    void Test ()
+    {
+        var x = true ? throw new NullReferenceException () : 1;
+        x = 2;
+        return;
+    }
+
+	static void Main () 
+	{
+	}
+}

mcs/errors/cs0173-6.cs

@@ -0,0 +1,10 @@
+// CS0173: Type of conditional expression cannot be determined because there is no implicit conversion between `throw expression' and `throw expression'
+// Line: 8
+
+class C
+{
+	public static void Test (bool b)
+	{
+		var s = b ? throw null : throw null;
+	}
+}

mcs/errors/cs0411-25.cs

@@ -0,0 +1,16 @@
+// CS0411: The type arguments for method `C.Foo<T>(System.Func<T>)' cannot be inferred from the usage. Try specifying the type arguments explicitly
+// Line: 10
+
+using System;
+
+public class C
+{
+    public static void Main ()
+    {
+        Foo (() => throw null);
+    }
+
+    static void Foo<T> (Func<T> arg)
+    {
+    }
+}

mcs/errors/cs1061-18.cs

@@ -0,0 +1,18 @@
+// CS1061: No overload for method `Call' takes `0' arguments
+// Line: 11
+
+using System;
+
+class Program
+{
+	static void Main ()
+	{
+		Action<dynamic, object> action = delegate { };
+		Foo (action).NoDynamicBinding ();
+	}
+
+	static T Foo<T>(Action<T, T> x)
+	{
+		throw new NotImplementedException ();
+	}
+}

mcs/errors/cs1617.cs

@@ -1,3 +1,3 @@
-// CS1617: Invalid -langversion option `ISO'. It must be `ISO-1', `ISO-2', Default or value in range 1 to 6
+// CS1617: Invalid -langversion option `ISO'. It must be `ISO-1', `ISO-2', Default or value in range 1 to 7
 // Line: 0
 // Compiler options: -langversion:ISO

mcs/errors/cs1644-51.cs

@@ -0,0 +1,8 @@
+// CS1644: Feature `throw expression' cannot be used because it is not part of the C# 6.0 language specification
+// Line: 5
+// Compiler options: -langversion:6
+
+static class Class
+{
+	int Prop => throw null;
+}

mcs/errors/cs4001-3.cs

@@ -0,0 +1,12 @@
+// CS4001: Cannot await `void' expression
+// Line: 10
+
+using System;
+
+class A
+{
+	static async void Test ()
+	{
+		await Console.WriteLine;
+	}
+}

mcs/errors/cs8188.cs

@@ -0,0 +1,13 @@
+// CS8188: An expression tree cannot not contain a throw expression
+// Line: 11
+
+using System;
+using System.Linq.Expressions;
+
+class C
+{
+	public static void Main ()
+	{
+		Expression<Func<object>> l = () => throw null;
+	}
+}

mcs/mcs/anonymous.cs

@@ -1652,9 +1652,10 @@ public override void FlowAnalysis (FlowAnalysisContext fc)
 			fc.TryFinally = prev_tf;
 		}
 
-		public override void MarkReachable (Reachability rc)
+		public override Reachability MarkReachable (Reachability rc)
 		{
 			block.MarkReachable (rc);
+			return rc;
 		}
 
 		public void SetHasThisAccess ()

mcs/mcs/assign.cs

@@ -503,11 +503,9 @@ public override void FlowAnalysis (FlowAnalysisContext fc)
 			}
 		}
 
-		public override void MarkReachable (Reachability rc)
+		public override Reachability MarkReachable (Reachability rc)
 		{
-			var es = source as ExpressionStatement;
-			if (es != null)
-				es.MarkReachable (rc);
+			return source.MarkReachable (rc);
 		}
 	}
 

mcs/mcs/async.cs

@@ -127,10 +127,9 @@ public override void EmitStatement (EmitContext ec)
 			stmt.EmitStatement (ec);
 		}
 
-		public override void MarkReachable (Reachability rc)
+		public override Reachability MarkReachable (Reachability rc)
 		{
-			base.MarkReachable (rc);
-			stmt.MarkReachable (rc);
+			return stmt.MarkReachable (rc);
 		}
 
 		public override object Accept (StructuralVisitor visitor)
@@ -514,11 +513,12 @@ public override void EmitStatement (EmitContext ec)
 			ec.Emit (OpCodes.Ret);
 		}
 
-		public override void MarkReachable (Reachability rc)
+		public override Reachability MarkReachable (Reachability rc)
 		{
 			//
 			// Reachability has been done in AsyncInitializerStatement
 			//
+			return rc;
 		}
 	}
 

mcs/mcs/convert.cs

@@ -744,6 +744,9 @@ public static bool ImplicitStandardConversionExists (Expression expr, TypeSpec t
 			if (expr_type == target_type)
 				return true;
 
+			if (expr_type == InternalType.ThrowExpr)
+				return target_type.Kind != MemberKind.InternalCompilerType;
+
 			if (target_type.IsNullableType)
 				return ImplicitNulableConversion (null, expr, target_type) != null;
 
@@ -1370,7 +1373,7 @@ static Expression ImplicitConversionStandard (ResolveContext ec, Expression expr
 			Expression e;
 
 			if (expr_type == target_type) {
-				if (expr_type != InternalType.NullLiteral && expr_type != InternalType.AnonymousMethod)
+				if (expr_type != InternalType.NullLiteral && expr_type != InternalType.AnonymousMethod && expr_type != InternalType.ThrowExpr)
 					return expr;
 				return null;
 			}
@@ -1396,6 +1399,10 @@ static Expression ImplicitConversionStandard (ResolveContext ec, Expression expr
 				return null;
 			}
 
+			if (expr_type == InternalType.ThrowExpr) {
+				return target_type.Kind == MemberKind.InternalCompilerType ? null : EmptyCast.Create (expr, target_type);
+			}
+
 			if (target_type.IsNullableType)
 				return ImplicitNulableConversion (ec, expr, target_type);
 

mcs/mcs/cs-parser.jay

@@ -219,7 +219,7 @@ namespace Mono.CSharp
 %token STRUCT	
 %token SWITCH	
 %token THIS	
-%token THROW	
+%token THROW
 %token TRUE	
 %token TRY	
 %token TYPEOF	
@@ -261,6 +261,7 @@ namespace Mono.CSharp
 %token WHEN
 %token INTERPOLATED_STRING
 %token INTERPOLATED_STRING_END
+%token THROW_EXPR
 
 /* C# keywords which are not really keywords */
 %token GET
@@ -4310,6 +4311,13 @@ unary_expression
 
 		$$ = new Await ((Expression) $2, GetLocation ($1));
 	  }
+	| THROW_EXPR prefixed_unary_expression
+	  {
+		if (lang_version < LanguageVersion.V_7)
+			FeatureIsNotAvailable (lexer.Location, "throw expression");
+
+		$$ = new ThrowExpression ((Expression) $2, GetLocation ($1));
+	  }
 	| BANG error
 	  {
 		Error_SyntaxError (yyToken);
@@ -6366,11 +6374,16 @@ return_statement
 	;
 
 throw_statement
-	: THROW opt_expression SEMICOLON
+	: THROW expression SEMICOLON
 	  {
 		$$ = new Throw ((Expression) $2, GetLocation ($1));
 		lbag.AddStatement ($$, GetLocation ($3));
 	  }
+	| THROW SEMICOLON
+	  {
+		$$ = new Throw (null, GetLocation ($1));
+		lbag.AddStatement ($$, GetLocation ($2));
+	  }
 	| THROW expression error
 	  {
 		Error_SyntaxError (yyToken);
@@ -8081,6 +8094,7 @@ static string GetTokenName (int token)
 	case Token.THIS:
 		return "this";
 	case Token.THROW:
+	case Token.THROW_EXPR:
 		return "throw";
 	case Token.TRUE:
 		return "true";

mcs/mcs/cs-tokenizer.cs

@@ -893,6 +893,17 @@ int GetKeyword (char[] id, int id_len)
 				if (parsing_block == 0)
 					res = -1;
 
+				break;
+			case Token.THROW:
+				switch (current_token) {
+				case Token.ARROW:
+				case Token.OP_COALESCING:
+				case Token.INTERR:
+				case Token.COLON:
+					res = Token.THROW_EXPR;
+					break;
+				}
+
 				break;
 			}
 
@@ -1345,6 +1356,7 @@ int TokenizePossibleNullableType ()
 			case Token.THIS:
 			case Token.NEW:
 			case Token.INTERPOLATED_STRING:
+			case Token.THROW:
 				next_token = Token.INTERR;
 				break;
 

mcs/mcs/ecore.cs

@@ -995,6 +995,11 @@ public virtual void FlowAnalysis (FlowAnalysisContext fc)
 		{
 		}
 
+		public virtual Reachability MarkReachable (Reachability rc)
+		{
+			return rc;
+		}
+
 		//
 		// Special version of flow analysis for expressions which can return different
 		// on-true and on-false result. Used by &&, ||, ?: expressions
@@ -1295,10 +1300,6 @@ public virtual object Accept (StructuralVisitor visitor)
 	/// </summary>
 	public abstract class ExpressionStatement : Expression
 	{
-		public virtual void MarkReachable (Reachability rc)
-		{
-		}
-
 		public virtual ExpressionStatement ResolveStatement (BlockContext ec)
 		{
 			Expression e = Resolve (ec);
@@ -1460,6 +1461,11 @@ public override SLE.Expression MakeExpression (BuilderContext ctx)
 #endif
 		}
 
+		public override Reachability MarkReachable (Reachability rc)
+		{
+			return child.MarkReachable (rc);
+		}
+
 		protected override void CloneTo (CloneContext clonectx, Expression t)
 		{
 			// Nothing to clone
@@ -2408,6 +2414,11 @@ public override SLE.Expression MakeExpression (BuilderContext ctx)
 		{
 			return orig_expr.MakeExpression (ctx);
 		}
+
+		public override Reachability MarkReachable (Reachability rc)
+		{
+			return expr.MarkReachable (rc);
+		}
 	}
 
 	//