When eating unexpected tokens in string interpolation, match opened '(' when looking for the closing ')'

Author: ahoppen

Sources/SwiftParser/Expressions.swift

@@ -1756,7 +1756,14 @@ extension Parser {
           var runexpectedTokens = [RawSyntax]()
           let runexpected: RawUnexpectedNodesSyntax?
           var loopProgress = LoopProgressCondition()
-          while !subparser.at(any: [.eof, .rightParen]) && loopProgress.evaluate(subparser.currentToken) {
+          var openParens = 0
+          // Terminate the loop when we've reached EOF or are at a ')' with no more open '(' that we need to skip
+          while !subparser.at(.eof) && !(subparser.at(.rightParen) && openParens == 0) && loopProgress.evaluate(subparser.currentToken) {
+            if subparser.at(.leftParen) {
+              openParens += 1
+            } else if subparser.at(.rightParen) {
+              openParens -= 1
+            }
             runexpectedTokens.append(RawSyntax(subparser.consumeAnyToken()))
           }
           if !runexpectedTokens.isEmpty {

Tests/SwiftParserTest/translated/UnclosedStringInterpolationTests.swift

@@ -81,7 +81,8 @@ final class UnclosedStringInterpolationTests: XCTestCase {
       let zzz = "\(x1️⃣; print(x)2️⃣
       """##,
       diagnostics: [
-        DiagnosticSpec(locationMarker: "1️⃣", message: "unexpected code '; print(x' in string literal"),
+        DiagnosticSpec(locationMarker: "1️⃣", message: "unexpected code '; print(x)' in string literal"),
+        DiagnosticSpec(locationMarker: "2️⃣", message: "expected ')' in string literal"),
         DiagnosticSpec(locationMarker: "2️⃣", message: #"expected '"' to end string literal"#),
       ]
     )
@@ -114,4 +115,16 @@ final class UnclosedStringInterpolationTests: XCTestCase {
     )
   }
 
+  func testSkipUnexpectedOpeningParensInStringLiteral() {
+    AssertParse(
+      #"""
+      "\(e 1️⃣H()r2️⃣
+      """#,
+      diagnostics: [
+        DiagnosticSpec(locationMarker: "1️⃣", message: "unexpected code 'H()r' in string literal"),
+        DiagnosticSpec(locationMarker: "2️⃣", message: "expected ')' in string literal"),
+        DiagnosticSpec(locationMarker: "2️⃣", message: #"expected '"' to end string literal"#),
+      ]
+    )
+  }
 }