Imprecise type analysis of window.document.elements

[stevemessick]

This is in dom:html, the definition of class Document (actually, the interface Element that it inherits from). The problem appears to be that the field elements has dynamic type even though the getter is defined as ElementList.

Since the type of window.document.elements is dynamic, code completion can offer no proposals, which surprised users (in a negative way).

TypeAnalyzer should return ElementList for the type of window.document.elements.

[stevemessick]

Has anyone had a chance to look at this issue yet?

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Set owner to mmendez@google.com.

[DartBot]

This comment was originally written by zundel@google.com

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The plot thickens:

#import('dart:html');

main() {
  bool isElementList = window.document.elements is ElementList;
  print ("isElementList=${isElementList}");
}

causes the compiler to run out of stack:

$ dartc_test /tmp/t.dart
java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:3057)
    at java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:117)
    at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:407)
    at java.lang.StringBuffer.append(StringBuffer.java:241)
    at java.io.StringWriter.write(StringWriter.java:101)
    at java.io.StringWriter.append(StringWriter.java:181)
    at java.io.StringWriter.append(StringWriter.java:41)
    at com.google.dart.compiler.backend.js.JavascriptBackend$CountingAppendable.append(JavascriptBackend.java:69)
    at com.google.common.io.CharStreams.copy(CharStreams.java:207)
    at com.google.dart.compiler.backend.js.JavascriptBackend$DepsWritingCallback.visitPart(JavascriptBackend.java:124)
    at com.google.dart.compiler.backend.js.AbstractJsBackend$DependencyBuilder.writePart(AbstractJsBackend.java:314)
    at com.google.dart.compiler.backend.js.AbstractJsBackend$DependencyBuilder.writeParts(AbstractJsBackend.java:292)
    at com.google.dart.compiler.backend.js.AbstractJsBackend$DependencyBuilder.build(AbstractJsBackend.java:128)
    at com.google.dart.compiler.backend.js.JavascriptBackend.packageLibs(JavascriptBackend.java:149)
    at com.google.dart.compiler.backend.js.JavascriptBackend.packageApp(JavascriptBackend.java:175)
    at com.google.dart.compiler.DartCompiler$Compiler.packageApp(DartCompiler.java:797)
    at com.google.dart.compiler.DartCompiler$Compiler.compile(DartCompiler.java:183)
    at com.google.dart.compiler.DartCompiler$Compiler.access$200(DartCompiler.java:122)
    at com.google.dart.compiler.DartCompiler.compileLib(DartCompiler.java:1148)
    at com.google.dart.runner.DartRunner.compileApp(DartRunner.java:308)
    at com.google.dart.runner.DartRunner.compileApp(DartRunner.java:296)
    at com.google.dart.runner.DartRunner.throwingMain(DartRunner.java:130)
    at com.google.dart.runner.DartRunner.main(DartRunner.java:98)

[stevemessick]

Thanks for taking a look.

This is the same problem seen in 1398. Please see the detailed analysis there.

From Element.dart:
  ElementList get elements();

  // TODO: The type of value should be Collection<Element>. See http://b/5392897
  void set elements(value);

[DartBot]

This comment was originally written by zundel@google.com

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The underlying problem is there is no type on this getter/setter. Apparently dartc chokec when the setter and getter did not have the same type, but that is no longer the case.

https://chromiumcodereview.appspot.com/9315061/

Once we get the updated library integrated, let me know if the problem persists.

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Set owner to zundel@google.com.

[DartBot]

This comment was originally written by zundel@google.com

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The problem persists: ref b/5392897

class Test<E> {
 Collection<E> _value;
 Set<E> get bar() { return _value; }
 void set bar( Collection<E> value) { _value =value; }
}

main() {
  Test<int> f = new Test<int>();
  f.bar().contains(3);
  f.bar.contains(3);
}

file:/tmp/foo2.dart:9: Use assignment to set field "bar" in Test<int>
     8: Test<int> f = new Test<int>();
     9: f.bar().contains(3);
file:/tmp/foo2.dart:10: Collection<int> has no method named "contains"
     9: f.bar().contains(3);
    10: f.bar.contains(3);

[stevemessick]

Marked this as blocking #1531.

[DartBot]

This comment was originally written by zundel@google.com

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Updated patch at https://chromiumcodereview.appspot.com/9315061/
Committed at r5136.

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Added Fixed label.