Support target-type new expressions.

[patrickt]

Right now this fails to parse:

        internal static class EnumFormatters
        {
            public static readonly EnumFormatter<AnalysisKind> AnalysisKind = new(value => (int)value, value => (AnalysisKind)value);
        }

failing at the = new( bit. I think this is the relevant piece of syntax.

[patrickt]

Note also that we don’t support interpolated strings appearing in declarations like these:

private static readonly string s_defaultDocumentPath = @$"Document\Path\{DefaultDocumentName}”;

[patrickt]

I think this bug is more general than just constant declarators.

[patrickt]

Here’s a hack that fixes this:

diff --git i/grammar.js w/grammar.js
index e6432dd..659783d 100644
--- i/grammar.js
+++ w/grammar.js
@@ -891,6 +891,14 @@ module.exports = grammar({
       field('body', choice($.block, $._expression))
     )),
 
+    direct_new_object_creation_expression: $ => seq(
+      'new',
+      '(',
+      commaSep($._expression),
+      optional(','),
+      ')'
+    ),
+
     anonymous_object_creation_expression: $ => seq(
       'new',
       '{',
@@ -1231,6 +1239,7 @@ module.exports = grammar({
     _expression: $ => choice(
       $.anonymous_method_expression,
       $.anonymous_object_creation_expression,
+      $.direct_new_object_creation_expression,
       $.array_creation_expression,
       $.assignment_expression,
       $.await_expression,

[initram]

The new without a type is a new C# 9 feature called target-type new expressions. This is the issue for it: dotnet/csharplang#100

So it is simply a new feature, not really a bug in the current syntax.

[initram]

Note also that we don’t support interpolated strings appearing in declarations like these:

private static readonly string s_defaultDocumentPath = @$"Document\Path\{DefaultDocumentName}”;

This was a new feature in C# 8, where you can use wither $@"Some string" or @$"Some string": https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8#enhancement-of-interpolated-verbatim-strings

I can create a PR to fix this.

[patrickt]

@initram Aha! I didn’t even notice that the characters were transposed. Thank you, and thanks for linking to the relevant chapter/verse of the standards.

[initram]

I think this issue can be closed now.