Enable language version 3.10 and format dot shorthands.

This is using a workaround for dart-lang/sdk#60840.
That issue is fixed and a new version of analyzer is published, but
unfortunately there is no corresponding version of test that works with
it so I can't upgrade yet.

The workaround is pretty harmless, so I'm fine with it. (The formatter
uses similar logic to handle commas which also aren't represented in the
AST nodes.)

Author: munificent

CHANGELOG.md

@@ -1,6 +1,8 @@
 ## 3.1.1-wip
 
-* Update to latest analyzer and enable language version 3.9.
+* Support dot shorthand syntax.
+* Enable language version 3.10.
+* Update to latest analyzer.
 
 ## 3.1.0
 

lib/src/dart_formatter.dart

@@ -34,7 +34,7 @@ final RegExp _widthCommentPattern = RegExp(r'^// dart format width=(\d+)$');
 final class DartFormatter {
   /// The latest Dart language version that can be parsed and formatted by this
   /// version of the formatter.
-  static final latestLanguageVersion = Version(3, 9, 0);
+  static final latestLanguageVersion = Version(3, 10, 0);
 
   /// The latest Dart language version that will be formatted using the older
   /// "short" style.

lib/src/front_end/ast_node_visitor.dart

@@ -589,6 +589,29 @@ final class AstNodeVisitor extends ThrowingAstVisitor<void> with PieceFactory {
     pieces.token(node.semicolon);
   }
 
+  @override
+  void visitDotShorthandInvocation(DotShorthandInvocation node) {
+    // TODO(rnystrom): Get this directly from the AST once the formatter can
+    // use analyzer 8.0.0.
+    // See: https://github.com/dart-lang/sdk/issues/60840
+    if (node.period.previous case var token?
+        when token.keyword == Keyword.CONST) {
+      pieces.token(token);
+      pieces.space();
+    }
+
+    pieces.token(node.period);
+    pieces.visit(node.memberName);
+    pieces.visit(node.typeArguments);
+    pieces.visit(node.argumentList);
+  }
+
+  @override
+  void visitDotShorthandPropertyAccess(DotShorthandPropertyAccess node) {
+    pieces.token(node.period);
+    pieces.visit(node.propertyName);
+  }
+
   @override
   void visitDottedName(DottedName node) {
     writeDotted(node.components);
@@ -2316,6 +2339,17 @@ final class AstNodeVisitor extends ThrowingAstVisitor<void> with PieceFactory {
     // Instead, we hoist the comment out of all of those and then have comment
     // precede them all so that they don't split.
     var firstToken = node.firstNonCommentToken;
+
+    // TODO(rnystrom): The AST node for DotShorthandInvocation in analyzer
+    // before 8.0.0 doesn't include a leading `const` as part of the node. If
+    // we ignore that, then a comment before the `.` gets incorrectly hoisted
+    // before the `const`. Remove this when we can upgrade to 8.0.0.
+    // See: https://github.com/dart-lang/sdk/issues/60840
+    if (node is DotShorthandInvocation &&
+        firstToken.previous?.keyword == Keyword.CONST) {
+      firstToken = firstToken.previous!;
+    }
+
     if (firstToken.precedingComments != null) {
       var comments = pieces.takeCommentsBefore(firstToken);
       var piece = pieces.build(() {

test/tall/invocation/dot_shorthand.stmt

@@ -0,0 +1,69 @@
+40 columns                              |
+(experiment dot-shorthands)
+>>> Getter.
+variable =  .  getter;
+<<< 3.9
+variable = .getter;
+>>> Method call with unsplit arguments.
+variable = .method(1,x:2,3,y:4);
+<<< 3.9
+variable = .method(1, x: 2, 3, y: 4);
+>>> Method call with split arguments.
+variable = .method(one, x: two, three, y: four);
+<<< 3.9
+variable = .method(
+  one,
+  x: two,
+  three,
+  y: four,
+);
+>>> Generic method call.
+variable =  .  method  <  int  ,  String  >  (  )  ;
+<<< 3.9
+variable = .method<int, String>();
+>>> Constructor.
+variable = .new(1);
+<<< 3.9
+variable = .new(1);
+>>> Const constructor.
+variable = const  .  new  (  );
+<<< 3.9
+variable = const .new();
+>>> Const named constructor.
+variable = const  .  named  (  );
+<<< 3.9
+variable = const .named();
+>>> Unsplit selector chain.
+v =  .  property  .  method()  .  x  .  another();
+<<< 3.9
+v = .property.method().x.another();
+>>> Split selector chain on shorthand getter.
+variable = .shorthand.method().another().third();
+<<< 3.9
+variable = .shorthand
+    .method()
+    .another()
+    .third();
+>>> Split selector chain on shorthand method.
+variable = .shorthand().method().getter.another().third();
+<<< 3.9
+variable = .shorthand()
+    .method()
+    .getter
+    .another()
+    .third();
+>>> Split in shorthand method call argument list.
+context(.shorthand(argument, anotherArgument, thirdArgument)
+.chain().another().third().fourthOne());
+<<< 3.9
+context(
+  .shorthand(
+        argument,
+        anotherArgument,
+        thirdArgument,
+      )
+      .chain()
+      .another()
+      .third()
+      .fourthOne(),
+);

test/tall/invocation/dot_shorthand_comment.stmt

@@ -0,0 +1,26 @@
+40 columns                              |
+(experiment dot-shorthands)
+>>> Line comment after dot.
+variable = . // Comment.
+whoDoesThis();
+<<< 3.9
+variable =
+    . // Comment.
+    whoDoesThis();
+>>> Block comment after dot.
+variable = ./* Comment. */whoDoesThis();
+<<< 3.9
+variable =
+    . /* Comment. */ whoDoesThis();
+>>> Line comment after `const`.
+variable = const // Comment.
+. whoDoesThis();
+<<< 3.9
+variable =
+    const // Comment.
+    .whoDoesThis();
+>>> Block comment after `const`.
+variable = const/* Comment. */.whoDoesThis();
+<<< 3.9
+variable =
+    const /* Comment. */ .whoDoesThis();