Filter lexical context to only effectful expr nodes

Author: stmontgomery

Sources/TestingMacros/ConditionMacro.swift

@@ -163,7 +163,7 @@ extension ConditionMacro {
       let commentsArrayExpr = ArrayExprSyntax {
         // Lexical context is ordered innermost-to-outermost, so reverse it to
         // maintain the expected order.
-        for lexicalSyntaxNode in context.lexicalContext.reversed() {
+        for lexicalSyntaxNode in context.lexicalContext.effectExpressions.reversed() {
           for commentTraitExpr in createCommentTraitExprs(for: lexicalSyntaxNode) {
             ArrayElementSyntax(expression: commentTraitExpr)
           }

Sources/TestingMacros/Support/EffectfulExpressionHandling.swift

@@ -12,7 +12,7 @@ import SwiftSyntax
 import SwiftSyntaxBuilder
 import SwiftSyntaxMacros
 
-// MARK: - Finding effect keywords
+// MARK: - Finding effect keywords and expressions
 
 /// A syntax visitor class that looks for effectful keywords in a given
 /// expression.
@@ -69,6 +69,19 @@ func findEffectKeywords(in node: some SyntaxProtocol, context: some MacroExpansi
   return effectFinder.effectKeywords
 }
 
+extension Sequence<Syntax> {
+  /// The syntax nodes in this sequence which are effectful expressions, such as
+  /// those for `try` or `await`.
+  var effectExpressions: some Sequence<Syntax> {
+    filter { node in
+      // This could be made simpler if/when swift-syntax introduces a protocol
+      // which all effectful expression syntax node types conform to.
+      // See https://github.com/swiftlang/swift-syntax/issues/3040
+      node.is(TryExprSyntax.self) || node.is(AwaitExprSyntax.self) || node.is(UnsafeExprSyntax.self)
+    }
+  }
+}
+
 // MARK: - Inserting effect keywords/thunks
 
 /// Make a function call expression to an effectful thunk function provided by

Tests/TestingMacrosTests/ConditionMacroTests.swift

@@ -277,6 +277,22 @@ struct ConditionMacroTests {
       // Comment for expect
       Testing.__checkValue(x, expression: .__fromSyntaxNode("x"), comments: [.__line("// Comment for try"), .__line("// Comment for await"), .__line("// Comment for expect")], isRequired: false, sourceLocation: Testing.SourceLocation.__here()).__expected()
       """,
+
+      """
+      // Ignore me
+      func example() {
+        // Capture me
+        #expect(x())
+      }
+      """:
+      """
+      func example() {
+        // Capture me
+        Testing.__checkFunctionCall((), calling: { _ in
+          x()
+        }, expression: .__fromFunctionCall(nil, "x"), comments: [.__line("// Capture me")], isRequired: false, sourceLocation: Testing.SourceLocation.__here()).__expected()
+      }
+      """,
     ]
   )
   func commentCapture(input: String, expectedOutput: String) throws {