Add more VB operator tests (dotnet/corefx#31320)

* Add VB operator tests

* Delete dead code from VB operators

* Add comparison operator tests

* Add more tests

* Fix VB handling of DBNull.Value

* Do all number parsing in the invariant culture

* Workaround https://github.com/dotnet/coreclr/issues/8648


Commit migrated from dotnet/corefx@7c745fb

src/libraries/Microsoft.VisualBasic/src/Microsoft/VisualBasic/CompilerServices/Operators.vb

@@ -10,6 +10,7 @@ Imports System.ComponentModel
 Imports System.Diagnostics
 Imports System.Globalization
 Imports System.Reflection
+Imports System.Runtime.CompilerServices
 
 Imports Microsoft.VisualBasic.CompilerServices.ExceptionUtils
 Imports Microsoft.VisualBasic.CompilerServices.Symbols
@@ -887,13 +888,7 @@ Namespace Microsoft.VisualBasic.CompilerServices
 
         Public Shared Function PlusObject(ByVal Operand As Object) As Object
 
-            If Operand Is Nothing Then
-                Return Boxed_ZeroInteger
-            End If
-
             Dim typ As TypeCode = GetTypeCode(Operand)
-
-
             Select Case typ
 
                 Case TypeCode.Empty
@@ -955,13 +950,6 @@ Namespace Microsoft.VisualBasic.CompilerServices
         Public Shared Function NegateObject(ByVal Operand As Object) As Object
 
             Dim tc As TypeCode = GetTypeCode(Operand)
-
-            If Operand Is Nothing Then
-                tc = TypeCode.Empty
-            Else
-                tc = Operand.GetType.GetTypeCode
-            End If
-
             Select Case tc
 
                 Case TypeCode.Empty
@@ -1123,13 +1111,7 @@ Namespace Microsoft.VisualBasic.CompilerServices
         End Function
 
         Private Shared Function NegateDecimal(ByVal operand As Decimal) As Object
-            'Using try/catch instead of check with MinValue since the overflow case should be very rare
-            'and a compare would be a big cost for the normal case.
-            Try
-                Return -operand
-            Catch ex As OverflowException
-                Return -CDbl(operand)
-            End Try
+            Return -operand
         End Function
 
         Private Shared Function NegateSingle(ByVal operand As Single) As Object
@@ -2498,7 +2480,8 @@ Namespace Microsoft.VisualBasic.CompilerServices
                 Case TypeCode.Empty * s_TCMAX + TypeCode.Decimal,
                      TypeCode.Empty * s_TCMAX + TypeCode.Single,
                      TypeCode.Empty * s_TCMAX + TypeCode.Double,
-                     TypeCode.Empty * s_TCMAX + TypeCode.String
+                     TypeCode.Empty * s_TCMAX + TypeCode.String,
+                     TypeCode.DBNull * s_TCMAX + TypeCode.String
 
                     Return Right
 
@@ -2760,7 +2743,8 @@ Namespace Microsoft.VisualBasic.CompilerServices
                 Case TypeCode.Decimal * s_TCMAX + TypeCode.Empty,
                      TypeCode.Single * s_TCMAX + TypeCode.Empty,
                      TypeCode.Double * s_TCMAX + TypeCode.Empty,
-                     TypeCode.String * s_TCMAX + TypeCode.Empty
+                     TypeCode.String * s_TCMAX + TypeCode.Empty,
+                     TypeCode.String * s_TCMAX + TypeCode.DBNull
 
                     Return Left
 
@@ -4601,6 +4585,7 @@ Namespace Microsoft.VisualBasic.CompilerServices
             Throw GetNoValidOperatorException(UserDefinedOperator.Modulus, Left, Right)
         End Function
 
+        <MethodImpl(MethodImplOptions.NoInlining)> ' To work around https://github.com/dotnet/coreclr/issues/8648
         Private Shared Function ModSByte(ByVal left As SByte, ByVal right As SByte) As Object
             Return left Mod right
         End Function
@@ -4610,27 +4595,18 @@ Namespace Microsoft.VisualBasic.CompilerServices
         End Function
 
         Private Shared Function ModInt16(ByVal left As Int16, ByVal right As Int16) As Object
-            Dim result As Integer = CInt(left) Mod CInt(right)
-
-            If result < Int16.MinValue OrElse result > Int16.MaxValue Then
-                Return result
-            Else
-                Return CShort(result)
-            End If
+            Return left Mod right
         End Function
 
         Private Shared Function ModUInt16(ByVal left As UInt16, ByVal right As UInt16) As Object
             Return left Mod right
         End Function
 
         Private Shared Function ModInt32(ByVal left As Integer, ByVal right As Integer) As Object
-            'Do operation with Int64 to avoid OverflowException with Int32.MinValue and -1
-            Dim result As Long = CLng(left) Mod CLng(right)
-
-            If result < Int32.MinValue OrElse result > Int32.MaxValue Then
-                Return result
+            If left = Integer.MinValue AndAlso right = -1 Then
+                Return 0
             Else
-                Return CInt(result)
+                Return left Mod right
             End If
         End Function
 
@@ -5131,9 +5107,30 @@ Namespace Microsoft.VisualBasic.CompilerServices
 #Region " Operator Concatenate & "
 
         Public Shared Function ConcatenateObject(ByVal Left As Object, ByVal Right As Object) As Object
+            Dim conv1, conv2 As IConvertible
+            Dim tc1, tc2 As TypeCode
 
-            Dim tc1 As TypeCode = GetTypeCode(Left)
-            Dim tc2 As TypeCode = GetTypeCode(Right)
+            conv1 = TryCast(Left, IConvertible)
+            If conv1 Is Nothing Then
+                If Left Is Nothing Then
+                    tc1 = TypeCode.Empty
+                Else
+                    tc1 = TypeCode.Object
+                End If
+            Else
+                tc1 = conv1.GetTypeCode()
+            End If
+
+            conv2 = TryCast(Right, IConvertible)
+            If conv2 Is Nothing Then
+                If Right Is Nothing Then
+                    tc2 = TypeCode.Empty
+                Else
+                    tc2 = TypeCode.Object
+                End If
+            Else
+                tc2 = conv2.GetTypeCode()
+            End If
 
             'Special cases for Char()
             If (tc1 = TypeCode.Object) AndAlso (TypeOf Left Is Char()) Then
@@ -5148,6 +5145,17 @@ Namespace Microsoft.VisualBasic.CompilerServices
                 Return InvokeUserDefinedOperator(UserDefinedOperator.Concatenate, Left, Right)
             End If
 
+            Dim LeftIsNull As Boolean = (tc1 = TypeCode.DBNull)
+            Dim RightIsNull As Boolean = (tc2 = TypeCode.DBNull)
+
+            If LeftIsNull And RightIsNull Then
+                Return Left
+            ElseIf LeftIsNull And Not RightIsNull Then
+                Left = ""
+            ElseIf RightIsNull And Not LeftIsNull Then
+                Right = ""
+            End If
+
             Return CStr(Left) & CStr(Right)
         End Function
 

src/libraries/Microsoft.VisualBasic/tests/Microsoft.VisualBasic.Tests.csproj

@@ -23,8 +23,9 @@
     <Compile Include="Microsoft/VisualBasic/CompilerServices/StandardModuleAttributeTests.cs" />
     <Compile Include="Microsoft/VisualBasic/Devices/NetworkAvailableEventArgsTests.cs" />
     <Compile Include="ConversionsTests.cs" />
-    <Compile Include="OperatorsTests.cs" />
     <Compile Include="DateAndTimeTests.cs" />
+    <Compile Include="OperatorsTests.cs" />
+    <Compile Include="OperatorsTests.Comparison.cs" />
     <Compile Include="InformationTests.cs" />
     <Compile Include="UtilsTests.cs" />
     <Compile Include="VBMathTests.cs" />