Format null-aware elements

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 3.0.2-wip
 
+* Format null-aware elements.
+
 * Don't indent conditional branches redundantly after `=`, `:`, and `=>`.
 
   ```dart

example/format.dart

@@ -78,7 +78,8 @@ Future<void> _runTest(String path, int line,
   var formatter = DartFormatter(
       languageVersion: formatTest.languageVersion,
       pageWidth: testFile.pageWidth,
-      indent: formatTest.leadingIndent);
+      indent: formatTest.leadingIndent,
+      experimentFlags: formatTest.experimentFlags);
 
   var actual = formatter.formatSource(formatTest.input);
 

lib/src/front_end/ast_node_visitor.dart

@@ -1251,7 +1251,24 @@ final class AstNodeVisitor extends ThrowingAstVisitor<void> with PieceFactory {
 
   @override
   void visitMapLiteralEntry(MapLiteralEntry node) {
-    writeAssignment(node.key, node.separator, node.value);
+    var leftPiece = pieces.build(() {
+      pieces.token(node.keyQuestion);
+      pieces.visit(node.key);
+    });
+
+    var operatorPiece = tokenPiece(node.separator);
+
+    var rightPiece = pieces.build(() {
+      pieces.token(node.valueQuestion);
+      pieces.visit(node.value, context: NodeContext.assignment);
+    });
+
+    pieces.add(AssignPiece(
+        left: leftPiece,
+        operatorPiece,
+        rightPiece,
+        canBlockSplitLeft: node.key.canBlockSplit,
+        canBlockSplitRight: node.value.canBlockSplit));
   }
 
   @override
@@ -1353,6 +1370,11 @@ final class AstNodeVisitor extends ThrowingAstVisitor<void> with PieceFactory {
     writePostfix(node.pattern, node.operator);
   }
 
+  @override
+  void visitNullAwareElement(NullAwareElement node) {
+    writePrefix(node.question, node.value);
+  }
+
   @override
   void visitNullCheckPattern(NullCheckPattern node) {
     writePostfix(node.pattern, node.operator);

lib/src/testing/test_file.dart

@@ -11,6 +11,7 @@ import '../../dart_style.dart';
 
 final _indentPattern = RegExp(r'\(indent (\d+)\)');
 final _versionPattern = RegExp(r'\(version (\d+)\.(\d+)\)');
+final _experimentPattern = RegExp(r'\(experiment ([a-z-]+)\)');
 final _unicodeUnescapePattern = RegExp(r'×([0-9a-fA-F]{2,4})');
 final _unicodeEscapePattern = RegExp('[\x0a\x0c\x0d]');
 
@@ -111,6 +112,14 @@ final class TestFile {
         return '';
       });
 
+      // Let the test enable experiments for features that are supported but not
+      // released yet.
+      var experiments = <String>[];
+      description = description.replaceAllMapped(_experimentPattern, (match) {
+        experiments.add(match[1]!);
+        return '';
+      });
+
       var inputComments = readComments();
 
       var inputBuffer = StringBuffer();
@@ -160,6 +169,7 @@ final class TestFile {
           lineNumber,
           languageVersion,
           leadingIndent,
+          experiments,
           inputComments,
           outputComments));
     }
@@ -217,6 +227,9 @@ final class FormatTest {
   /// line.
   final int leadingIndent;
 
+  /// Experiments that should be enabled when running this test.
+  final List<String> experimentFlags;
+
   FormatTest(
       this.input,
       this.output,
@@ -225,6 +238,7 @@ final class FormatTest {
       this.line,
       this.languageVersion,
       this.leadingIndent,
+      this.experimentFlags,
       this.inputComments,
       this.outputComments);
 

pubspec.yaml

@@ -9,7 +9,7 @@ environment:
   sdk: "^3.4.0"
 
 dependencies:
-  analyzer: ">=6.5.0 <8.0.0"
+  analyzer: ">=7.3.0 <8.0.0"
   args: ">=1.0.0 <3.0.0"
   collection: "^1.17.0"
   package_config: ^2.1.0

test/tall/expression/collection_null_aware.stmt

@@ -0,0 +1,28 @@
+40 columns                              |
+>>> (experiment null-aware-elements) List element.
+var list = [  ?  x  ];
+<<<
+var list = [?x];
+>>> (experiment null-aware-elements) Set element.
+var set = {  ?  x  };
+<<<
+var set = {?x};
+>>> (experiment null-aware-elements) Map key.
+var map = {  ?  key  : value};
+<<<
+var map = {?key: value};
+>>> (experiment null-aware-elements) Map value.
+var map = { key:  ?  value  };
+<<<
+var map = {key: ?value};
+>>> (experiment null-aware-elements) Both key and value.
+var map = {  ?  key  :  ?  value  };
+<<<
+var map = {?key: ?value};
+>>> (experiment null-aware-elements) Split inside element.
+var list = [?(veryLongExpression +thatIsForcedToSplit)];
+<<<
+var list = [
+  ?(veryLongExpression +
+      thatIsForcedToSplit),
+];

test/tall/expression/collection_null_aware_comment.stmt

@@ -0,0 +1,34 @@
+40 columns                              |
+>>> (experiment null-aware-elements) Inline comment after `?`.
+var list = [  ?  /* c */  x  ];
+<<<
+var list = [? /* c */ x];
+>>> (experiment null-aware-elements)
+var map = {  ?  /* c */  key  :  ?  /* c */  value  };
+<<<
+var map = {
+  ? /* c */ key: ? /* c */ value,
+};
+>>> (experiment null-aware-elements) Line comment after `?`.
+var list = [  ?  // c
+x  ];
+<<<
+### This is an odd place for a comment so the formatting is odd, but we want to
+### at least pin it down with a test.
+var list = [
+  ? // c
+  x,
+];
+>>> (experiment null-aware-elements)
+var map = {  ?  // c
+key  :  ?  // c
+value  };
+<<<
+### This is an odd place for a comment so the formatting is odd, but we want to
+### at least pin it down with a test.
+var map = {
+  ? // c
+      key:
+      ? // c
+      value,
+};

test/utils.dart

@@ -130,7 +130,8 @@ void _testFile(TestFile testFile) {
         var formatter = DartFormatter(
             languageVersion: formatTest.languageVersion,
             pageWidth: testFile.pageWidth,
-            indent: formatTest.leadingIndent);
+            indent: formatTest.leadingIndent,
+            experimentFlags: formatTest.experimentFlags);
 
         var actual = _validateFormat(
             formatter,

tool/update_tests.dart

@@ -92,7 +92,8 @@ Future<void> _updateTestFile(TestFile testFile) async {
     var formatter = DartFormatter(
         languageVersion: formatTest.languageVersion,
         pageWidth: testFile.pageWidth,
-        indent: formatTest.leadingIndent);
+        indent: formatTest.leadingIndent,
+        experimentFlags: formatTest.experimentFlags);
 
     var actual = formatter.formatSource(formatTest.input);
 
@@ -110,6 +111,8 @@ Future<void> _updateTestFile(TestFile testFile) async {
         : DartFormatter.latestShortStyleLanguageVersion;
 
     var descriptionParts = [
+      for (var experiment in formatTest.experimentFlags)
+        '(experiment $experiment)',
       if (formatTest.leadingIndent != 0) '(indent ${formatTest.leadingIndent})',
       if (formatTest.languageVersion != defaultLanguageVersion)
         '(version ${formatTest.languageVersion.major}.'