Fasta type inference prototype #2

pkg/front_end/lib/src/fasta/type_inference/local_type_inferrer.dart

Index: pkg/front_end/lib/src/fasta/type_inference/local_type_inferrer.dart
diff --git a/pkg/front_end/lib/src/fasta/type_inference/local_type_inferrer.dart b/pkg/front_end/lib/src/fasta/type_inference/local_type_inferrer.dart
new file mode 100644
index 0000000000000000000000000000000000000000..b8e2a4beff1b1f1956eb87d94a77f0db98d2b334
--- /dev/null
+++ b/pkg/front_end/lib/src/fasta/type_inference/local_type_inferrer.dart
@@ -0,0 +1,82 @@
+import 'package:kernel/ast.dart' show DartType;
+
+import 'package:kernel/core_types.dart';
+
+import '../builder/shadow_ast.dart';
+
+class LocalTypeInferrer {
+  final CoreTypes coreTypes;
+
+  LocalTypeInferrer(this.coreTypes);
+
+  void finishVariableDeclaration(
+      DartType type, Expression initializer, VariableDeclaration variable) {
+    // TODO(paulberry): is this needed at all?
+    // throw new UnimplementedError();
+  }
+
+  void recordReturnStatement(OldFunctionContext function, Expression expr) {
+    function?._returnExpressions?.add(expr);
+  }
+
+  OldFunctionContext nestFunctionContext(OldFunctionContext outer) {
+    return new OldFunctionContext();
+  }
+
+  void inferBody(Statement statement) {
+    statement.shadowInfer(this, null);
+  }
+
+  DartType union(DartType a, DartType b) {
+    if (a == null) return b;
+    throw new UnimplementedError();
+  }
+}
+
+class FunctionContext {
+  final LocalTypeInferrer inferrer;
+
+  final bool returnTypeNeeded;
+
+  final bool isAsync;
+
+  final bool isGenerator;
+
+  DartType _inferredReturnType;
+
+  FunctionContext(
+      this.inferrer, this.returnTypeNeeded, this.isAsync, this.isGenerator);
+
+  get inferredReturnType {
+    if (_inferredReturnType == null) {
+      // No return statement found.
+      throw new UnimplementedError();
+    }
+    return _inferredReturnType;
+  }
+
+  void recordReturnType(DartType type) {
+    _inferredReturnType = inferrer.union(_inferredReturnType, type);
+  }
+}
+
+/// TODO(paulberry): is this needed at all?
+class OldFunctionContext {
+  var _returnExpressions = <Expression>[];
+
+  List<VariableDeclaration> _positionalFormals;
+
+  bool _isAsync = false;
+
+  void recordAsyncModifier(bool isAsync) {
+    _isAsync = isAsync;
+  }
+
+  void recordFormals(
+      int requiredParameterCount,
+      List<VariableDeclaration> positionalFormals,
+      List<VariableDeclaration> namedFormals) {
+    // TODO(paulberry): handle requiredParameterCount and namedFormals.
+    _positionalFormals = positionalFormals;
+  }
+}