[cfe] Internal ASTs for dot shorthand exprs and head with no arguments.

Two new internal ASTs for the CFE representing the entire dot shorthand expression (DotShorthand) and the dot shorthand head (DotShorthandPropertyGet) without arguments.
Static method invocations/constructor calls will be handled later.

Setting up the ASTS first, there's no tests yet. I'll use these in the upcoming CLs.

Bug: #59758
Change-Id: I91a052a3c954a00a424426d3be5c3007aaebc775
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/410902
Commit-Queue: Kallen Tu <[email protected]>
Reviewed-by: Chloe Stefantsova <[email protected]>
Reviewed-by: Johnni Winther <[email protected]>

Author: kallentu

pkg/front_end/lib/src/kernel/forest.dart

@@ -927,6 +927,18 @@ class Forest {
     return new IfCaseStatement(expression, patternGuard, then, otherwise)
       ..fileOffset = fileOffset;
   }
+
+  // Coverage-ignore(suite): Not run.
+  DotShorthand createDotShorthandContext(
+      int fileOffset, Expression innerExpression) {
+    return new DotShorthand(innerExpression)..fileOffset = fileOffset;
+  }
+
+  // Coverage-ignore(suite): Not run.
+  DotShorthandPropertyGet createDotShorthandPropertyGet(
+      int fileOffset, Name name) {
+    return new DotShorthandPropertyGet(name)..fileOffset = fileOffset;
+  }
 }
 
 class _VariablesDeclaration extends AuxiliaryStatement {

pkg/front_end/lib/src/kernel/internal_ast.dart

@@ -3221,3 +3221,59 @@ class ExtensionTypeRepresentationFieldInitializer extends InternalInitializer {
   String toString() =>
       'ExtensionTypeRepresentationFieldInitializer(${toStringInternal()})';
 }
+
+// Coverage-ignore(suite): Not run.
+/// Internal expression for a dot shorthand.
+///
+/// This node wraps around the [innerExpression] and indicates to the
+/// [InferenceVisitor] that we need to save the context type of the expression.
+class DotShorthand extends InternalExpression {
+  /// The entire dot shorthand expression (e.g. `.zero` or `.parse(input)`).
+  Expression innerExpression;
+
+  DotShorthand(this.innerExpression);
+
+  @override
+  ExpressionInferenceResult acceptInference(
+      InferenceVisitorImpl visitor, DartType typeContext) {
+    return visitor.visitDotShorthand(this, typeContext);
+  }
+
+  @override
+  String toString() {
+    return "DotShorthand(${toStringInternal()})";
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    printer.writeExpression(innerExpression);
+  }
+}
+
+// Coverage-ignore(suite): Not run.
+/// Internal expression for a dot shorthand head with no arguments.
+/// (e.g. `.zero`).
+///
+/// This node could represent a shorthand of a static get or a tearoff.
+class DotShorthandPropertyGet extends InternalExpression {
+  Name name;
+
+  DotShorthandPropertyGet(this.name);
+
+  @override
+  ExpressionInferenceResult acceptInference(
+      InferenceVisitorImpl visitor, DartType typeContext) {
+    return visitor.visitDotShorthandPropertyGet(this, typeContext);
+  }
+
+  @override
+  String toString() {
+    return "DotShorthandPropertyGet(${toStringInternal()})";
+  }
+
+  @override
+  void toTextInternal(AstPrinter printer) {
+    printer.write('.');
+    printer.writeName(name);
+  }
+}

pkg/front_end/lib/src/type_inference/inference_visitor.dart

@@ -12103,6 +12103,20 @@ class InferenceVisitorImpl extends InferenceVisitorBase
   StatementInferenceResult visitAuxiliaryStatement(AuxiliaryStatement node) {
     return _unhandledStatement(node);
   }
+
+  // Coverage-ignore(suite): Not run.
+  ExpressionInferenceResult visitDotShorthand(
+      DotShorthand node, DartType typeContext) {
+    // TODO(kallentu): Implementation needed for dot shorthands.
+    return _unhandledExpression(node, typeContext);
+  }
+
+  // Coverage-ignore(suite): Not run.
+  ExpressionInferenceResult visitDotShorthandPropertyGet(
+      DotShorthandPropertyGet node, DartType typeContext) {
+    // TODO(kallentu): Implementation needed for dot shorthands.
+    return _unhandledExpression(node, typeContext);
+  }
 }
 
 /// Offset and type information collection in [InferenceVisitor.inferMapEntry].

pkg/front_end/test/coverage_suite_expected.dart

@@ -590,7 +590,7 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
   ),
   // 100.0%.
   "package:front_end/src/kernel/body_builder.dart": (
-    hitCount: 7192,
+    hitCount: 7188,
     missCount: 0,
   ),
   // 100.0%.