Fix it to emit a single diagnostic when both open and close quote are missing

Author: TTOzzi

Sources/SwiftParserDiagnostics/MissingNodesError.swift

@@ -281,6 +281,12 @@ public struct MissingNodesError: ParserError {
       return nil
     }
 
+    if missingNodes.count == 2,
+      missingNodes.allSatisfy({ $0.as(TokenSyntax.self)?.tokenKind == .stringQuote })
+    {
+      return "in \(anchorTypeName)"
+    }
+
     let isFirstTokenStartMarker = missingNodes.first?.as(TokenSyntax.self)?.tokenKind.isStartMarker ?? false
     let isLastTokenEndMarker = missingNodes.last?.as(TokenSyntax.self)?.tokenKind.isEndMarker ?? false
     switch (isFirstTokenStartMarker, isLastTokenEndMarker) {
@@ -364,7 +370,10 @@ extension ParseDiagnosticsGenerator {
           missingNodes += [sibling]
         } else if sibling.isMissingAllTokens && sibling.hasTokens {
           missingNodes += [sibling]
-        } else if sibling.kind.isSyntaxCollection && sibling.children(viewMode: .sourceAccurate).count == 0 {
+        } else if sibling.kind.isSyntaxCollection
+          && (sibling.children(viewMode: .sourceAccurate).count == 0
+            || sibling.children(viewMode: .sourceAccurate).only?.kind == .stringSegment)
+        {
           // Skip over any syntax collections without any elements while looking ahead for further missing nodes.
         } else {
           // Otherwise we have found a present node, so stop looking ahead.

Tests/SwiftParserTest/AttributeTests.swift

@@ -454,19 +454,14 @@ final class AttributeTests: XCTestCase {
 
     assertParse(
       """
-      @_expose(Cxx, 1️⃣baz2️⃣) func foo() {}
+      @_expose(Cxx, 1️⃣baz) func foo() {}
       """,
       diagnostics: [
         DiagnosticSpec(
           locationMarker: "1️⃣",
-          message: #"expected '"' in string literal"#,
-          fixIts: [#"insert '"'"#]
-        ),
-        DiagnosticSpec(
-          locationMarker: "2️⃣",
-          message: #"expected '"' to end string literal"#,
-          fixIts: [#"insert '"'"#]
-        ),
+          message: #"expected '""' in string literal"#,
+          fixIts: [#"insert '""'"#]
+        )
       ],
       fixedSource: """
         @_expose(Cxx, "baz") func foo() {}
@@ -543,20 +538,15 @@ final class AttributeTests: XCTestCase {
 
     assertParse(
       """
-      @_unavailableFromAsync(message: 1️⃣abc2️⃣)
+      @_unavailableFromAsync(message: 1️⃣abc)
       func foo() {}
       """,
       diagnostics: [
         DiagnosticSpec(
           locationMarker: "1️⃣",
-          message: #"expected '"' in string literal"#,
-          fixIts: [#"insert '"'"#]
-        ),
-        DiagnosticSpec(
-          locationMarker: "2️⃣",
-          message: #"expected '"' to end string literal"#,
-          fixIts: [#"insert '"'"#]
-        ),
+          message: #"expected '""' in string literal"#,
+          fixIts: [#"insert '""'"#]
+        )
       ],
       fixedSource: """
         @_unavailableFromAsync(message: "abc")

Tests/SwiftParserTest/translated/OriginalDefinedInAttrTests.swift

@@ -86,13 +86,8 @@ final class OriginalDefinedInAttrTests: XCTestCase {
         ),
         DiagnosticSpec(
           locationMarker: "1️⃣",
-          message: #"expected '"' in string literal"#,
-          fixIts: [#"insert '"'"#]
-        ),
-        DiagnosticSpec(
-          locationMarker: "2️⃣",
-          message: #"expected '"' to end string literal"#,
-          fixIts: [#"insert '"'"#]
+          message: #"expected '""' in string literal"#,
+          fixIts: [#"insert '""'"#]
         ),
         DiagnosticSpec(
           locationMarker: "2️⃣",