[de minimis] Core IDE Support for VB string interpolation

The vast majority of this came from ADGreen (thanks Anthony!), which in turn had a great deal ported from the work I'd done in C#.  At this point, I'm not sure *who* wrote this code. It's shelvesets all the way down.

* Automatic brace completion
* Formatting
* Completion list
* Brace matching
* Classification (changeset 1390884)

Src/Workspaces/VisualBasic/Portable/Classification/ClassificationHelpers.vb

@@ -17,12 +17,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Classification
         Public Function GetClassification(token As SyntaxToken) As String
             If SyntaxFacts.IsKeywordKind(token.Kind) Then
                 Return ClassificationTypeNames.Keyword
+            ElseIf IsStringToken(token) Then
+                Return ClassificationTypeNames.StringLiteral
             ElseIf SyntaxFacts.IsPunctuation(token.Kind) Then
                 Return ClassifyPunctuation(token)
             ElseIf token.Kind = SyntaxKind.IdentifierToken Then
                 Return ClassifyIdentifierSyntax(token)
-            ElseIf token.IsKind(SyntaxKind.StringLiteralToken, SyntaxKind.CharacterLiteralToken) Then
-                Return ClassificationTypeNames.StringLiteral
             ElseIf token.IsNumericLiteral() Then
                 Return ClassificationTypeNames.NumericLiteral
             ElseIf token.Kind = SyntaxKind.XmlNameToken Then
@@ -45,7 +45,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Classification
             ElseIf token.IsKind(SyntaxKind.None, SyntaxKind.BadToken) Then
                 Return Nothing
             Else
-                Return Contract.FailWithReturn(Of String)("Unhandled token kind: " & token.Kind)
+                Return Contract.FailWithReturn(Of String)("Unhandled token kind: " & token.Kind().ToString())
             End If
         End Function
 
@@ -88,6 +88,15 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Classification
             End If
         End Function
 
+        Private Function IsStringToken(token As SyntaxToken) As Boolean
+            If token.IsKind(SyntaxKind.StringLiteralToken, SyntaxKind.CharacterLiteralToken, SyntaxKind.InterpolatedStringTextToken) Then
+                Return True
+            End If
+
+            Return token.IsKind(SyntaxKind.DollarSignDoubleQuoteToken, SyntaxKind.DoubleQuoteToken) AndAlso
+                   token.Parent.IsKind(SyntaxKind.InterpolatedStringExpression)
+        End Function
+
         Private Function ClassifyTypeDeclarationIdentifier(identifier As SyntaxToken) As String
             Select Case identifier.Parent.Kind
                 Case SyntaxKind.ClassStatement

Src/Workspaces/VisualBasic/Portable/Extensions/ContextQuery/SyntaxTreeExtensions.vb

 ' Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 Imports System.Runtime.CompilerServices
-Imports Microsoft.CodeAnalysis.Text
-Imports Microsoft.CodeAnalysis.VisualBasic
-Imports Microsoft.CodeAnalysis.VisualBasic.Extensions
-Imports Microsoft.CodeAnalysis.VisualBasic.Symbols
 Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
 Imports Microsoft.CodeAnalysis.VisualBasic.Utilities
 Imports System.Threading
@@ -309,6 +305,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions.ContextQuery
                targetToken.IsChildToken(Of IfStatementSyntax)(Function(ifStatement) ifStatement.IfKeyword) OrElse
                targetToken.IsChildToken(Of ElseIfStatementSyntax)(Function(elseIfStatement) elseIfStatement.ElseIfKeyword) OrElse
                targetToken.IsChildToken(Of InferredFieldInitializerSyntax)(Function(inferredField) inferredField.KeyKeyword) OrElse
+               targetToken.IsChildToken(Of InterpolationSyntax)(Function(interpolation) interpolation.OpenBraceToken) OrElse
                targetToken.IsChildToken(Of EqualsValueSyntax)(Function(initializer) initializer.EqualsToken) OrElse
                targetToken.IsChildToken(Of JoinClauseSyntax)(Function(joinQuery) joinQuery.OnKeyword) OrElse
                targetToken.IsChildSeparatorToken(Of JoinClauseSyntax, JoinConditionSyntax)(Function(joinQuery) joinQuery.JoinConditions) OrElse

Src/Workspaces/VisualBasic/Portable/Formatting/Rules/AdjustSpaceFormattingRule.vb

@@ -258,6 +258,40 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Formatting
                 Return CreateAdjustSpacesOperation(1, AdjustSpacesOption.ForceSpacesIfOnSingleLine)
             End If
 
+            ' No space after $" at the start of an interpolated string
+            If previousToken.Kind = SyntaxKind.DollarSignDoubleQuoteToken AndAlso previousToken.Parent.IsKind(SyntaxKind.InterpolatedStringExpression) Then
+                Return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpaces)
+            End If
+
+            ' No space before " at the end of an interpolated string
+            If currentToken.Kind = SyntaxKind.DoubleQuoteToken AndAlso currentToken.Parent.IsKind(SyntaxKind.InterpolatedStringExpression) Then
+                Return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpaces)
+            End If
+
+            ' No space before { Or after } in interpolations
+            If (currentToken.Kind = SyntaxKind.OpenBraceToken AndAlso currentToken.Parent.IsKind(SyntaxKind.Interpolation)) OrElse
+               (previousToken.Kind = SyntaxKind.CloseBraceToken AndAlso previousToken.Parent.IsKind(SyntaxKind.Interpolation)) Then
+                Return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpaces)
+            End If
+
+            ' Preserve space after { Or before } in interpolations (i.e. between the braces And the expression)
+            If (previousToken.Kind = SyntaxKind.OpenBraceToken AndAlso previousToken.Parent.IsKind(SyntaxKind.Interpolation)) OrElse
+               (currentToken.Kind = SyntaxKind.CloseBraceToken AndAlso currentToken.Parent.IsKind(SyntaxKind.Interpolation)) Then
+                Return CreateAdjustSpacesOperation(0, AdjustSpacesOption.PreserveSpaces)
+            End If
+
+            ' No space before Or after , in interpolation alignment clause
+            If (previousToken.Kind = SyntaxKind.CommaToken AndAlso previousToken.Parent.IsKind(SyntaxKind.InterpolationAlignmentClause)) OrElse
+               (currentToken.Kind = SyntaxKind.CommaToken AndAlso currentToken.Parent.IsKind(SyntaxKind.InterpolationAlignmentClause)) Then
+                Return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpaces)
+            End If
+
+            ' No space before Or after : in interpolation format clause
+            If (previousToken.Kind = SyntaxKind.ColonToken AndAlso previousToken.Parent.IsKind(SyntaxKind.InterpolationFormatClause)) OrElse
+               (currentToken.Kind = SyntaxKind.ColonToken AndAlso currentToken.Parent.IsKind(SyntaxKind.InterpolationFormatClause)) Then
+                Return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpaces)
+            End If
+
             ' * }
             ' * )
             ' * ,
@@ -353,7 +387,6 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Formatting
                 Return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpacesIfOnSingleLine)
             End If
 
-
             Return nextFunc.Invoke()
         End Function
     End Class

Src/Workspaces/VisualBasicTest/Formatting/FormattingTests.vb

@@ -4018,5 +4018,123 @@ End Module
 
             AssertFormatLf2CrLf(text.Value, expected.Value)
         End Sub
+
+        <Fact, Trait(Traits.Feature, Traits.Features.Formatting)>
+        Public Sub InterpolatedString1()
+            Dim text = <Code>
+Class C
+    Sub M()
+        Dim a = "World"
+        Dim b =$"Hello,  {a}"
+    End Sub
+End Class
+</Code>
+
+            Dim expected = <Code>
+Class C
+    Sub M()
+        Dim a = "World"
+        Dim b = $"Hello,  {a}"
+    End Sub
+End Class
+</Code>
+
+            AssertFormatLf2CrLf(text.Value, expected.Value)
+        End Sub
+
+        <Fact, Trait(Traits.Feature, Traits.Features.Formatting)>
+        Public Sub InterpolatedString2()
+            Dim text = <Code>
+Class C
+    Sub M()
+        Dim a = "Hello"
+        Dim b = "World"
+        Dim c = $"{a}, {b}"
+    End Sub
+End Class
+</Code>
+
+            Dim expected = <Code>
+Class C
+    Sub M()
+        Dim a = "Hello"
+        Dim b = "World"
+        Dim c = $"{a}, {b}"
+    End Sub
+End Class
+</Code>
+
+            AssertFormatLf2CrLf(text.Value, expected.Value)
+        End Sub
+
+        <Fact, Trait(Traits.Feature, Traits.Features.Formatting)>
+        Public Sub InterpolatedString3()
+            Dim text = <Code>
+Class C
+    Sub M()
+        Dim a = "World"
+        Dim b = $"Hello, { a }"
+    End Sub
+End Class
+</Code>
+
+            Dim expected = <Code>
+Class C
+    Sub M()
+        Dim a = "World"
+        Dim b = $"Hello, { a }"
+    End Sub
+End Class
+</Code>
+
+            AssertFormatLf2CrLf(text.Value, expected.Value)
+        End Sub
+
+        <Fact, Trait(Traits.Feature, Traits.Features.Formatting)>
+        Public Sub InterpolatedString4()
+            Dim text = <Code>
+Class C
+    Sub M()
+        Dim a = "Hello"
+        Dim b = "World"
+        Dim c = $"{ a }, { b }"
+    End Sub
+End Class
+</Code>
+
+            Dim expected = <Code>
+Class C
+    Sub M()
+        Dim a = "Hello"
+        Dim b = "World"
+        Dim c = $"{ a }, { b }"
+    End Sub
+End Class
+</Code>
+
+            AssertFormatLf2CrLf(text.Value, expected.Value)
+        End Sub
+
+        <Fact, Trait(Traits.Feature, Traits.Features.Formatting)>
+        Public Sub InterpolatedString5()
+            Dim text = <Code>
+Class C
+    Sub M()
+        Dim s = $"{42 , -4 :x}"
+    End Sub
+End Class
+</Code>
+
+            Dim expected = <Code>
+Class C
+    Sub M()
+        Dim s = $"{42,-4:x}"
+    End Sub
+End Class
+</Code>
+
+            AssertFormatLf2CrLf(text.Value, expected.Value)
+        End Sub
+
     End Class
 End Namespace
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