Fix IndexOutOfRangeException when running operation actions over Roslyn sources.

src/Compilers/CSharp/Portable/BoundTree/Expression.cs

@@ -97,22 +97,22 @@ internal static ImmutableArray<IArgument> DeriveArguments(ImmutableArray<BoundEx
                     argumentIndex = argumentsToParameters.IndexOf(parameterIndex);
                 }
 
-                // No argument has been supplied for the parameter at `parameterIndex`:
-                // 1. `argumentIndex == -1' when the arguments are specified out of parameter order, and no argument is provided for parameter corresponding to `parameters[parameterIndex]`.
-                // 2. `argumentIndex >= boundArguments.Length` when the arguments are specified in parameter order, and no argument is provided at `parameterIndex`.
                 if (argumentIndex == -1 || argumentIndex >= boundArguments.Length)
                 {
+                    // No argument has been supplied for the parameter at `parameterIndex`:
+                    // 1. `argumentIndex == -1' when the arguments are specified out of parameter order, and no argument is provided for parameter corresponding to `parameters[parameterIndex]`.
+                    // 2. `argumentIndex >= boundArguments.Length` when the arguments are specified in parameter order, and no argument is provided at `parameterIndex`.
+
                     Symbols.ParameterSymbol parameter = parameters[parameterIndex];
-                    // Corresponding parameter is optional with default value.
                     if (parameter.HasExplicitDefaultValue)
                     {
+                        // The parameter is optional with a default value.
                         arguments.Add(new Argument(ArgumentKind.DefaultValue, parameter, new Literal(parameter.ExplicitDefaultConstantValue, parameter.Type, null)));
                     }
                     else
                     {
-                        // If corresponding parameter is Param array, then this means 0 element is provided and an Argument of kind == ParamArray will be added, 
-                        // otherwise it is an error and null is added.
-                        arguments.Add(DeriveArgument(parameterIndex, argumentIndex, boundArguments, argumentNames, argumentRefKinds, parameters, invocationSyntax));
+                        // The parameter might be a params array, in which case an empty array will be provided.
+                        arguments.Add(DeriveArgument(parameterIndex, boundArguments.Length, boundArguments, argumentNames, argumentRefKinds, parameters, invocationSyntax));
                     }
                 }
                 else

src/Compilers/CSharp/Test/Semantic/Diagnostics/OperationAnalyzerTests.cs

@@ -1145,6 +1145,27 @@ public void M1()
         M0(1, new int[] { 2, 3, 4 });
         M0(1, new int[] { 2, 3, 4, 5 });
         M0(1, new int[] { 2, 3, 4, 5, 6 });
+        M2(1, c: 2);
+        D d = new D(3, c: 40);
+        d = new D(""Hello"", 1, 2, 3, 4);
+        d = new D(""Hello"", new int[] { 1, 2, 3, 4 });
+        d = new D(""Hello"", 1, 2, 3);
+        d = new D(""Hello"", new int[] { 1, 2, 3 });
+    }
+
+    public void M2(int a, int b = 10, int c = 20, params int[] d)
+    {
+    }
+
+    class D
+    {
+        public D(int a, int b = 10, int c = 20, params int[] d)
+        {
+        }
+
+        public D(string a, params int[] b)
+        {
+        }
     }
 }
 ";
@@ -1158,7 +1179,9 @@ public void M1()
                 Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "new int[] { 2, 3, 4, 5 }").WithLocation(16, 15),
                 Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "new int[] { 2, 3, 4, 5 }").WithLocation(16, 15),
                 Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "new int[] { 2, 3, 4, 5, 6 }").WithLocation(17, 15),
-                Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "new int[] { 2, 3, 4, 5, 6 }").WithLocation(17, 15)
+                Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "new int[] { 2, 3, 4, 5, 6 }").WithLocation(17, 15),
+                Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "1").WithLocation(20, 28),
+                Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "new int[] { 1, 2, 3, 4 }").WithLocation(21, 28)
                 );
         }
 

src/Compilers/Core/CodeAnalysisTest/Diagnostics/OperationTestAnalyzer.cs

@@ -1070,6 +1070,29 @@ public sealed override void Initialize(AnalysisContext context)
                      }
                  },
                  OperationKind.InvocationExpression);
+
+            context.RegisterOperationAction(
+                (operationContext) =>
+                {
+                    IObjectCreationExpression creation = (IObjectCreationExpression)operationContext.Operation;
+                    
+                    foreach (IArgument argument in creation.ArgumentsInParameterOrder)
+                    {
+                        if (argument.Parameter.IsParams)
+                        {
+                            IArrayCreationExpression arrayValue = argument.Value as IArrayCreationExpression;
+                            if (arrayValue != null)
+                            {
+                                Optional<object> dimensionSize = arrayValue.DimensionSizes[0].ConstantValue;
+                                if (dimensionSize.HasValue && IntegralValue(dimensionSize.Value) > 3)
+                                {
+                                    operationContext.ReportDiagnostic(Diagnostic.Create(LongParamsDescriptor, argument.Value.Syntax.GetLocation()));
+                                }
+                            }
+                        }
+                    }
+                },
+                OperationKind.ObjectCreationExpression);
         }
 
         private static long IntegralValue(object value)

src/Compilers/VisualBasic/Test/Semantic/Diagnostics/OperationAnalyzerTests.vb

@@ -1191,6 +1191,15 @@ Class C
         M0(1, New Integer() { 2, 3, 4 })
         M0(1, New Integer() { 2, 3, 4, 5 })
         M0(1, New Integer() { 2, 3, 4, 5, 6 })
+        Dim local As D = new D(1, 2, 3, 4, 5)
+        local = new D(1, New Integer() { 2, 3, 4, 5 })
+        local = new D(1, 2, 3, 4)
+        local = new D(1, New Integer() { 2, 3, 4 })
+    End Sub
+End Class
+
+Class D
+    Public Sub New(a As Integer, ParamArray b As Integer())
     End Sub
 End Class
 ]]>
@@ -1207,7 +1216,9 @@ End Class
                                            Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "New Integer() { 2, 3, 4, 5 }").WithLocation(12, 15),
                                            Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "New Integer() { 2, 3, 4, 5 }").WithLocation(12, 15),
                                            Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "New Integer() { 2, 3, 4, 5, 6 }").WithLocation(13, 15),
-                                           Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "New Integer() { 2, 3, 4, 5, 6 }").WithLocation(13, 15))
+                                           Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "New Integer() { 2, 3, 4, 5, 6 }").WithLocation(13, 15),
+                                           Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "D").WithLocation(14, 30),
+                                           Diagnostic(ParamsArrayTestAnalyzer.LongParamsDescriptor.Id, "New Integer() { 2, 3, 4, 5 }").WithLocation(15, 26))
         End Sub
 
         <Fact>