Add support for CollectionExpression in async generator (#963)

Author: j3parker

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
       - uses: Brightspace/third-party-actions@actions/setup-dotnet
         with:
           dotnet-version: |
-            7.0.x
+            9.0.x
 
       - name: Build
         run: dotnet build -c Release

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
 	<PropertyGroup>
 		<Deterministic>true</Deterministic>
-		<LangVersion>10.0</LangVersion>
+		<LangVersion>12.0</LangVersion>
 		<ImplicitUsings>true</ImplicitUsings>
 		<InvariantGlobalization>true</InvariantGlobalization>
 		<Nullable>enable</Nullable>

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "7.0.300",
+    "version": "9.0.101",
     "rollForward": "latestFeature"
   }
 }

src/D2L.CodeStyle.Analyzers/Async/Generator/AsyncToSyncMethodTransformer.cs

@@ -258,6 +258,9 @@ private ExpressionSyntax Transform( ExpressionSyntax expr )
 				.WithLeft( Transform( binExpr.Left ) )
 				.WithRight( Transform( binExpr.Right ) ),
 
+			CollectionExpressionSyntax collectionExpr =>
+				collectionExpr.WithElements( Transform( collectionExpr.Elements ) ),
+
 			ConditionalExpressionSyntax condExpr => condExpr
 				.WithCondition( Transform( condExpr.Condition ) )
 				.WithWhenTrue( Transform( condExpr.WhenTrue ) )
@@ -352,6 +355,17 @@ private VariableDesignationSyntax Transform( VariableDesignationSyntax des )
 			_ => UnhandledSyntax( des )
 		};
 
+	private SeparatedSyntaxList<CollectionElementSyntax> Transform(
+		SeparatedSyntaxList<CollectionElementSyntax> original
+	) => SyntaxFactory.SeparatedList(
+		original.Select( elem => elem switch {
+			ExpressionElementSyntax ee => ee.WithExpression( Transform( ee.Expression ) ),
+			SpreadElementSyntax sp => sp.WithExpression( Transform( sp.Expression ) ),
+			_ => UnhandledSyntax( elem )
+		} ),
+		original.GetSeparators()
+	);
+
 	private StatementSyntax Transform( ExpressionStatementSyntax exprStmt ) {
 		var result = Transform( exprStmt.Expression );
 

tests/D2L.CodeStyle.Analyzers.Test/Async/Generator/AsyncToSyncMethodTransformerTests.cs

@@ -633,6 +633,41 @@ public void ImplicitObjectCreation() {
 		Assert.AreEqual( "[Blocking] T Hello() { return new( Foo() ); }", actual.Value.ToFullString() );
 	}
 
+	[Test]
+	public void CollectionSyntax() {
+		var actual = Transform(
+			"""
+			[GenerateSync]
+			async Task<IEnumerable<int>> HelloAsync()
+				=> [
+					await FooAsync(),
+					3,
+					..(await BarAsync()),
+					4,
+					await XAsync() + await YAsync()
+				];
+			"""
+		);
+			
+
+		Assert.IsTrue( actual.Success );
+		Assert.IsEmpty( actual.Diagnostics );
+		Assert.AreEqual(
+			"""
+			[Blocking]
+			IEnumerable<int> Hello()
+				=> [
+					Foo(),
+					3,
+					..(Bar()),
+					4,
+					X() + Y()
+				];
+			""",
+			actual.Value.ToFullString()
+		);
+			
+	}
 
 	// loosly assert that the right sorts of diagnostics came out
 	private static void AssertDiagnostics( IEnumerable<Diagnostic> actual, params DiagnosticDescriptor[] expected ) {