Reduce strong mode errors and warnings

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

Index: pkg/front_end/lib/src/fasta/kernel/body_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index 9b304e488f675c3b6fcc619d83f7e83b90c576de..07d30ce2306e05649c086688368f1f0c4623ed6b 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -236,8 +236,13 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
   }
 
   Block popBlock(int count) {
-    List<Statement> statements = popList(count) ?? <Statement>[];
-    List<Statement> copy;
+    List statements = popList(count) ?? <Statement>[];
+    // TODO(sigmund): should be List<Statement>. In strong mode the .addAll
+    // below shows an error (and will fail at runtime). The core issue is that
+    // `statements` is a List< Statement or List<Statement>>, but we expect that
+    // some of the nested lists will have a reified type of List not
+    // List<Statement>.

[ahe, 2017/02/07 11:03:07]

How about:

List<dynamic /* Statement | List<Statement> */> statements = popList(count) ??
<Statement>[];

And remove the todo.

[Siggi Cherem (dart-lang), 2017/02/07 21:59:25]

Done. added the comment on the type, but had to do something else for the TODO
(below)

+    List copy;

[ahe, 2017/02/07 11:03:07]

This should be List<Statement>.

[Siggi Cherem (dart-lang), 2017/02/07 21:59:25]

Done. Sorry for the confusion - the TODO was referring to this `List`. I
originally removed the explicit type arg as a way to workaround
https://github.com/dart-lang/sdk/issues/28651. (same issue as
`variableOrExpression` below and with formals in the outline_builder.)

There are two ways to work around it here, either removing the type-arg here or
adding a silly assignment further below. I just switched to the latter and made
the comment highlight the issue. Hope this is clearer.

     for (int i = 0; i < statements.length; i++) {
       var statement = statements[i];
       if (statement is List) {
@@ -505,7 +510,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
   void endSend(Token token) {
     debugEvent("Send");
     Arguments arguments = pop();
-    List typeArguments = pop();
+    List<DartType> typeArguments = pop();
     Object receiver = pop();
     if (arguments != null && typeArguments != null) {
       arguments.types.addAll(typeArguments);
@@ -993,7 +998,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
       assert(conditionStatement is EmptyStatement);
     }
     List<VariableDeclaration> variables = <VariableDeclaration>[];
-    var variableOrExpression = pop();
+    dynamic variableOrExpression = pop();
     Statement begin;
     if (variableOrExpression is BuilderAccessor) {
       variableOrExpression = variableOrExpression.buildForEffect();
@@ -1001,7 +1006,9 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
     if (variableOrExpression is VariableDeclaration) {
       variables.add(variableOrExpression);
     } else if (variableOrExpression is List) {
-      variables.addAll(variableOrExpression);
+      // TODO(sigmund): remove this assignment (see issue #28651)
+      Iterable vars = variableOrExpression;
+      variables.addAll(vars);
     } else if (variableOrExpression == null) {
       // Do nothing.
     } else if (variableOrExpression is Expression) {
@@ -1161,7 +1168,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
     // TODO(ahe): The scope is wrong for return types of generic functions.
     debugEvent("Type");
     List<DartType> arguments = pop();
-    var name = pop();
+    dynamic name = pop();
     if (name is List) {
       if (name.length != 2) {
         return internalError("Unexpected: $name.length");
@@ -1281,7 +1288,8 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
             name.fileOffset);
       }
       if (thisKeyword == null) {
-        variable = builder.build();
+        KernelFormalParameterBuilder formalBuilder = builder;

[ahe, 2017/02/07 11:03:08]

Remove this.

[Siggi Cherem (dart-lang), 2017/02/07 21:59:25]

Done.

+        variable = formalBuilder.build();
         variable.initializer = name.initializer;
       } else if (builder.isField && builder.parent == classBuilder) {
         FieldBuilder field = builder;
@@ -1504,7 +1512,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
     Identifier suffix = popIfNotNull(periodBeforeName);
     Identifier identifier;
     List<DartType> typeArguments = pop();
-    var type = pop();
+    dynamic type = pop();
     if (type is List) {
       var prefix = type[0];
       identifier = type[1];
@@ -1621,7 +1629,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
     debugEvent("NewExpression");
     Arguments arguments = pop();
     String name = pop();
-    List typeArguments = pop();
+    List<DartType> typeArguments = pop();
     var type = pop();
 
     if (typeArguments != null) {
@@ -1630,7 +1638,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
     }
 
     String errorName;
-    if (type is ClassBuilder) {
+    if (type is KernelClassBuilder) {

[ahe, 2017/02/07 11:03:07]

Change this back.

[Siggi Cherem (dart-lang), 2017/02/07 21:59:25]

Sorry, I totally meant to ask you a follow up question about this: below there
are two accesses to `type.cls` that are producing an error because `cls` is only
defined in KernelClassBuilder.

On what cases can this be a non-kernel class builder?

[ahe, 2017/02/08 19:59:23]

I don't think it can happen currently, but I'd like to keep the type test and
fix the problems below. I've added some suggestions.

[Siggi Cherem (dart-lang), 2017/02/09 04:44:02]

Done.

       Builder b = type.findConstructorOrFactory(name);
       Member target;
       if (b == null) {
@@ -1743,7 +1751,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
       exitLocalScope();
     }
     FormalParameters formals = pop();
-    List typeParameters = pop();
+    List<TypeParameter> typeParameters = pop();
     push(formals.addToFunction(new FunctionNode(body,
                 typeParameters: typeParameters, asyncMarker: asyncModifier)));
     functionNestingLevel--;
@@ -1769,7 +1777,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
     AsyncMarker asyncModifier = pop();
     exitLocalScope();
     FormalParameters formals = pop();
-    List typeParameters = pop();
+    List<TypeParameter> typeParameters = pop();
     FunctionNode function = formals.addToFunction(new FunctionNode(body,
             typeParameters: typeParameters, asyncMarker: asyncModifier));
     push(new FunctionExpression(function));