Implement KernelNoSuchMethodResolver.

pkg/compiler/lib/src/kernel/no_such_method_resolver.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.
 
 part of dart2js.kernel.element_map;
 
 class KernelNoSuchMethodResolver implements NoSuchMethodResolver {
   final KernelToElementMap elementMap;
 
   KernelNoSuchMethodResolver(this.elementMap);
 
+  ElementEnvironment get _elementEnvironment => elementMap.elementEnvironment;
+
+  CommonElements get _commonElements => elementMap.commonElements;
+
   @override
   bool hasForwardingSyntax(KFunction method) {
-    throw new UnimplementedError(
-        "KernelNoSuchMethodResolver.hasForwardingSyntax");
+    ir.Procedure node = elementMap._memberList[method.memberIndex].node;

[Siggi Cherem (dart-lang), 2017/05/03 17:29:49]

Since we are preparing to move this file as a separate library and make some
public (but restricted APIs) to fetch kernel from the KElements, maybe we can
take the first step here and add a lookup for these (and hide all the .index
uses within the file that defines the environment.)

We can still keep it private (e.g. _lookupProcedure(method))

[Johnni Winther, 2017/05/04 09:13:36]

Done.

+    if (node.function.positionalParameters.isEmpty) return false;
+    ir.VariableDeclaration firstParameter =
+        node.function.positionalParameters.first;
+    ir.Statement body = node.function.body;
+    ir.Expression expr;
+    if (body is ir.ReturnStatement) {
+      expr = body.expression;
+    } else if (body is ir.Block && body.statements.isNotEmpty) {

[Siggi Cherem (dart-lang), 2017/05/03 17:29:49]

ha - the old implementation checked that statements.length == 1 (so a silly case
like: 
  noSuchMethod(i) {
    return super.noSuchMethod(i);
    return foo;
  }

was not recognized before, but it will be recognized now.

[Johnni Winther, 2017/05/04 09:13:35]

Ahh - I thought I was equally silly...

+      ir.Statement first = body.statements.first;
+      if (first is ir.ReturnStatement) {
+        expr = first.expression;
+      }
+    }
+    if (expr is ir.AsExpression &&
+        elementMap.getDartType(expr.type) == _commonElements.dynamicType) {
+      ir.AsExpression asExpression = expr;
+      expr = asExpression.operand;
+    }
+    if (expr is ir.SuperMethodInvocation &&
+        expr.name.name == Identifiers.noSuchMethod_) {
+      ir.Arguments arguments = expr.arguments;
+      if (arguments.positional.length == 1 &&
+          arguments.named.isEmpty &&
+          arguments.positional.first is ir.VariableGet) {
+        ir.VariableGet get = arguments.positional.first;
+        return get.variable == firstParameter;
+      }
+    }
+    return false;
   }
 
   @override
   bool hasThrowingSyntax(KFunction method) {
-    throw new UnimplementedError(
-        "KernelNoSuchMethodResolver.hasThrowingSyntax");
+    ir.Procedure node = elementMap._memberList[method.memberIndex].node;
+    ir.Statement body = node.function.body;
+    ir.Expression expr;
+    if (body is ir.ReturnStatement) {
+      expr = body.expression;
+    } else if (body is ir.ExpressionStatement) {
+      expr = body.expression;
+    } else if (body is ir.Block && body.statements.isNotEmpty) {

[Siggi Cherem (dart-lang), 2017/05/03 17:29:49]

nit: move this out first, so we can reuse the other two conditions:

ir.Statement body = node.function.body;
if (body is ir.Block && body.statements.isNotEmpty) {
  body = body.statements.first;
}
if (body is ir.ReturnStatement) {
  expr = body.expression;
} else if (body is ir.ExpressionStatement) {
  expr = body.expression;
}
return expr is ir.Throw;

[Johnni Winther, 2017/05/04 09:13:36]

Done.

+      ir.Statement first = body.statements.first;
+      if (first is ir.ReturnStatement) {
+        expr = first.expression;
+      } else if (first is ir.ExpressionStatement) {
+        expr = first.expression;
+      }
+    }
+    return expr is ir.Throw;
   }
 
   @override
   FunctionEntity getSuperNoSuchMethod(FunctionEntity method) {
-    throw new UnimplementedError(
-        "KernelNoSuchMethodResolver.getSuperNoSuchMethod");
+    ClassEntity cls = method.enclosingClass;
+    while (cls != null) {
+      cls = _elementEnvironment.getSuperClass(cls);
+      MemberEntity member =
+          _elementEnvironment.lookupClassMember(cls, Identifiers.noSuchMethod_);
+      if (member != null) {
+        if (member.isFunction) {
+          FunctionEntity function = member;
+          if (function.parameterStructure.positionalParameters >= 1) {
+            return function;
+          }
+        }
+        break;

[Siggi Cherem (dart-lang), 2017/05/03 17:29:49]

not sure what this case does - if you have a noSuchMethod that is a getter or
has the wrong signature, you'll return Object.noSuchMethod below, was that the
intent?

[Johnni Winther, 2017/05/04 09:13:36]

Yep. That's the spec!

+      }
+    }
+    FunctionEntity function = _elementEnvironment.lookupClassMember(
+        _commonElements.objectClass, Identifiers.noSuchMethod_);
+    assert(invariant(method, function != null,
+        message: "No super noSuchMethod found for $method."));
+    return function;
   }
 }