Issue 30179. Infer return type of static setters to 'void'.

pkg/analyzer/test/src/task/strong/front_end_inference_test.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:front_end/src/base/instrumentation.dart' as fasta;
+import 'package:front_end/src/fasta/compiler_command_line.dart' as fasta;
 import 'package:front_end/src/fasta/compiler_context.dart' as fasta;
-import 'package:front_end/src/fasta/compiler_command_line.dart' as fasta;
 import 'package:front_end/src/fasta/testing/validating_instrumentation.dart'
     as fasta;
 import 'package:front_end/src/fasta/util/relativize.dart' show relativizeUri;
 import 'package:kernel/kernel.dart' as fasta;
 import 'package:path/path.dart' as pathos;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../dart/analysis/base.dart';
 
@@ skipping 350 matching lines @@
   visitDeclaredIdentifier(DeclaredIdentifier node) {
     super.visitDeclaredIdentifier(node);
     if (node.type == null) {
       _recordType(node.identifier.offset, node.element.type);
     }
   }
 
   @override
   visitFunctionDeclaration(FunctionDeclaration node) {
     super.visitFunctionDeclaration(node);
-    if (node.element is LocalElement &&
-        node.element.enclosingElement is! CompilationUnitElement) {
+
+    bool isSetter = node.element.kind == ElementKind.SETTER;
+    bool isLocalFunction = node.element is LocalElement &&
+        node.element.enclosingElement is! CompilationUnitElement;
+
+    if (isSetter || isLocalFunction) {
       if (node.returnType == null) {
         _instrumentation.record(
             uri,
             node.name.offset,
-            'returnType',
+            isSetter ? 'topType' : 'returnType',
             new _InstrumentationValueForType(
                 node.element.returnType, elementNamer));
       }
       var parameters = node.functionExpression.parameters;
       for (var parameter in parameters.parameters) {
         // Note: it's tempting to check `parameter.type == null`, but that
         // doesn't work because of function-typed formal parameter syntax.
         if (parameter.element.hasImplicitType) {
           _recordType(parameter.identifier.offset, parameter.element.type);
         }
@@ skipping 80 matching lines @@
       DartType type = node.staticType;
       if (type is InterfaceType) {
         _recordTypeArguments(node.offset, type.typeArguments);
       }
     }
   }
 
   @override
   visitMethodDeclaration(MethodDeclaration node) {
     super.visitMethodDeclaration(node);
+    if (node.returnType == null) {
+      _recordTopType(node.name.offset, node.element.returnType);
+    }
     if (node.element.enclosingElement is ClassElement && !node.isStatic) {
-      if (node.returnType == null) {
-        _recordTopType(node.name.offset, node.element.returnType);
-      }
       if (node.parameters != null) {
         for (var parameter in node.parameters.parameters) {
           // Note: it's tempting to check `parameter.type == null`, but that
           // doesn't work because of function-typed formal parameter syntax.
           if (parameter.element.hasImplicitType) {
             _recordTopType(parameter.identifier.offset, parameter.element.type);
           }
         }
       }
     }
@@ skipping 124 matching lines @@
 
   /// Based on DDC code generator's `_recoverTypeArguments`
   Iterable<DartType> _recoverTypeArguments(FunctionType g, FunctionType f) {
     assert(identical(g.element, f.element));
     assert(g.typeFormals.isNotEmpty && f.typeFormals.isEmpty);
     assert(g.typeFormals.length + g.typeArguments.length ==
         f.typeArguments.length);
     return f.typeArguments.skip(g.typeArguments.length);
   }
 }