Fix throw switch-expr; by specifying the typeHint for throw.

ICSharpCode.Decompiler.Tests/TestCases/Pretty/SwitchExpressions.cs

@@ -244,6 +244,15 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 			}).ToValidated();
 		}
 
+		public static void ThrowDifferentExceptions(int i)
+		{
+			throw i switch {
+				0 => (Exception)new ArgumentException("Invalid argument"),
+				1 => new InvalidOperationException("Invalid operation"),
+				_ => new NotSupportedException(),
+			};
+		}
+
 		public static int SwitchOnStringImplicitDefault(string s)
 		{
 			return s switch {

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -1272,7 +1272,8 @@ namespace ICSharpCode.Decompiler.CSharp
 
 		protected internal override TranslatedExpression VisitThrow(Throw inst, TranslationContext context)
 		{
-			return new ThrowExpression(Translate(inst.Argument))
+			var ex = Translate(inst.Argument, typeHint: compilation.FindType(KnownTypeCode.Exception));
+			return new ThrowExpression(ex)
 				.WithILInstruction(inst)
 				.WithRR(new ThrowResolveResult());
 		}

ICSharpCode.Decompiler/CSharp/StatementBuilder.cs

@@ -434,7 +434,8 @@ namespace ICSharpCode.Decompiler.CSharp
 
 		protected internal override TranslatedStatement VisitThrow(Throw inst)
 		{
-			return new ThrowStatement(exprBuilder.Translate(inst.Argument)).WithILInstruction(inst);
+			var ex = exprBuilder.Translate(inst.Argument, typeHint: typeSystem.FindType(KnownTypeCode.Exception));
+			return new ThrowStatement(ex).WithILInstruction(inst);
 		}
 
 		protected internal override TranslatedStatement VisitRethrow(Rethrow inst)