[CFE] Fail silently on invalid constructs during constant evaluation.
This acts as a stable backstop for situations where Fasta fails to
rewrite various erroneous constructs into invalid expressions.
Change-Id: Ibaac3d62b9cfdc597c0f85aadf9aec2920689222
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/97511
Reviewed-by: Kevin Millikin <kmillikin@google.com>
Commit-Queue: Aske Simon Christensen <askesc@google.com>
diff --git a/pkg/front_end/lib/src/fasta/fasta_codes_generated.dart b/pkg/front_end/lib/src/fasta/fasta_codes_generated.dart
index f255d8f..3f0e063 100644
--- a/pkg/front_end/lib/src/fasta/fasta_codes_generated.dart
+++ b/pkg/front_end/lib/src/fasta/fasta_codes_generated.dart
@@ -1217,6 +1217,38 @@
// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
const Template<
Message Function(
+ String string,
+ Constant
+ _constant)> templateConstEvalInvalidPropertyGet = const Template<
+ Message Function(String string, Constant _constant)>(
+ messageTemplate:
+ r"""The property '#string' can't be accessed on '#constant' within a const context.""",
+ withArguments: _withArgumentsConstEvalInvalidPropertyGet);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String string, Constant _constant)>
+ codeConstEvalInvalidPropertyGet =
+ const Code<Message Function(String string, Constant _constant)>(
+ "ConstEvalInvalidPropertyGet", templateConstEvalInvalidPropertyGet,
+ analyzerCodes: <String>["CONST_EVAL_THROWS_EXCEPTION"]);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsConstEvalInvalidPropertyGet(
+ String string, Constant _constant) {
+ if (string.isEmpty) throw 'No string provided';
+ TypeLabeler labeler = new TypeLabeler();
+ List<Object> constantParts = labeler.labelConstant(_constant);
+ String constant = constantParts.join();
+ return new Message(codeConstEvalInvalidPropertyGet,
+ message:
+ """The property '${string}' can't be accessed on '${constant}' within a const context.""" +
+ labeler.originMessages,
+ arguments: {'string': string, 'constant': _constant});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+ Message Function(
String
name)> templateConstEvalInvalidStaticInvocation = const Template<
Message Function(String name)>(
diff --git a/pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart b/pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart
index 79aa7f5..e8527f0 100644
--- a/pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart
@@ -48,6 +48,7 @@
templateConstEvalInvalidType,
templateConstEvalInvalidBinaryOperandType,
templateConstEvalInvalidMethodInvocation,
+ templateConstEvalInvalidPropertyGet,
templateConstEvalInvalidStaticInvocation,
templateConstEvalInvalidStringInterpolationOperand,
templateConstEvalInvalidSymbolName,
@@ -478,17 +479,27 @@
errorReporter.report(locatedMessage, contextMessages);
return new UnevaluatedConstant(new InvalidExpression(e.message.message));
} on _AbortDueToInvalidExpression catch (e) {
- errorReporter.reportInvalidExpression(e.node);
- return new UnevaluatedConstant(e.node);
+ // TODO(askesc): Copy position from erroneous node.
+ // Currently not possible, as it might be in a different file.
+ // Can be done if we add an explicit URI to InvalidExpression.
+ InvalidExpression invalid = new InvalidExpression(e.message);
+ if (invalid.fileOffset == TreeNode.noOffset) {
+ invalid.fileOffset = node.fileOffset;
+ }
+ errorReporter.reportInvalidExpression(invalid);
+ return new UnevaluatedConstant(invalid);
}
}
+ /// Report an error that has been detected during constant evaluation.
Null report(TreeNode node, Message message, {List<LocatedMessage> context}) {
throw new _AbortDueToError(node, message, context: context);
}
- Null reportInvalidExpression(InvalidExpression node) {
- throw new _AbortDueToInvalidExpression(node);
+ /// Report a construct that should not occur inside a potentially constant
+ /// expression. It is assumed that an error has already been reported.
+ Null reportInvalid(TreeNode node, String message) {
+ throw new _AbortDueToInvalidExpression(node, message);
}
/// Produce an unevaluated constant node for an expression.
@@ -575,7 +586,8 @@
defaultTreeNode(Node node) {
// Only a subset of the expression language is valid for constant
// evaluation.
- throw 'Constant evaluation has no support for ${node.runtimeType} yet!';
+ return reportInvalid(
+ node, 'Constant evaluation has no support for ${node.runtimeType}!');
}
visitNullLiteral(NullLiteral node) => nullConstant;
@@ -707,15 +719,18 @@
final Constructor constructor = node.target;
final Class klass = constructor.enclosingClass;
if (!constructor.isConst) {
- throw 'The front-end should ensure we do not encounter a '
- 'constructor invocation of a non-const constructor.';
+ return reportInvalid(node, 'Non-const constructor invocation.');
}
if (constructor.function.body != null &&
constructor.function.body is! EmptyStatement) {
- throw 'Constructor "$node" has non-trivial body "${constructor.function.body.runtimeType}".';
+ return reportInvalid(
+ node,
+ 'Constructor "$node" has non-trivial body '
+ '"${constructor.function.body.runtimeType}".');
}
if (klass.isAbstract) {
- throw 'Constructor "$node" belongs to abstract class "${klass}".';
+ return reportInvalid(
+ node, 'Constructor "$node" belongs to abstract class "${klass}".');
}
final positionals = evaluatePositionalArguments(node.arguments);
@@ -993,8 +1008,10 @@
}
}
} else {
- throw new Exception(
- 'No support for handling initializer of type "${init.runtimeType}".');
+ return reportInvalid(
+ constructor,
+ 'No support for handling initializer of type '
+ '"${init.runtimeType}".');
}
}
});
@@ -1002,7 +1019,7 @@
}
visitInvalidExpression(InvalidExpression node) {
- return reportInvalidExpression(node);
+ return reportInvalid(node, node.message);
}
visitMethodInvocation(MethodInvocation node) {
@@ -1260,12 +1277,16 @@
visitPropertyGet(PropertyGet node) {
if (node.receiver is ThisExpression) {
// Access "this" during instance creation.
+ if (instanceBuilder == null) {
+ return reportInvalid(node, 'Instance field access outside constructor');
+ }
for (final Field field in instanceBuilder.fields.keys) {
if (field.name == node.name) {
return instanceBuilder.fields[field];
}
}
- throw 'Could not evaluate field get ${node.name} on incomplete instance';
+ return reportInvalid(node,
+ 'Could not evaluate field get ${node.name} on incomplete instance');
}
final Constant receiver = _evaluateSubexpression(node.receiver);
@@ -1283,7 +1304,10 @@
} else if (receiver is NullConstant) {
return report(node, messageConstEvalNullValue);
}
- throw 'Could not evaluate property get on $receiver.';
+ return report(
+ node,
+ templateConstEvalInvalidPropertyGet.withArguments(
+ node.name.name, receiver));
}
visitLet(Let node) {
@@ -1310,8 +1334,7 @@
if (variable.isConst) {
return _evaluateSubexpression(variable.initializer);
}
- throw new Exception('The front-end should ensure we do not encounter a '
- 'variable get of a non-const variable.');
+ return reportInvalid(node, 'Variable get of a non-const variable.');
}
visitStaticGet(StaticGet node) {
@@ -1340,8 +1363,8 @@
templateConstEvalInvalidStaticInvocation
.withArguments(target.name.name));
} else {
- throw new Exception(
- 'No support for ${target.runtimeType} in a static-get.');
+ reportInvalid(
+ node, 'No support for ${target.runtimeType} in a static-get.');
}
});
}
@@ -1530,14 +1553,15 @@
return canonicalize(
new PartialInstantiationConstant(constant, typeArguments));
}
- throw new Exception(
+ return reportInvalid(
+ node,
'The number of type arguments supplied in the partial instantiation '
'does not match the number of type arguments of the $constant.');
}
// The inner expression in an instantiation can never be null, since
// instantiations are only inferred on direct references to declarations.
- throw new Exception(
- 'Only tear-off constants can be partially instantiated.');
+ return reportInvalid(
+ node, 'Only tear-off constants can be partially instantiated.');
}
@override
@@ -1701,7 +1725,7 @@
return a > b ? trueConstant : falseConstant;
}
- throw new Exception("Unexpected binary numeric operation '$op'.");
+ return reportInvalid(node, "Unexpected binary numeric operation '$op'.");
}
Library libraryOf(TreeNode node) {
@@ -1793,9 +1817,10 @@
}
class _AbortDueToInvalidExpression {
- final InvalidExpression node;
+ final TreeNode node;
+ final String message;
- _AbortDueToInvalidExpression(this.node);
+ _AbortDueToInvalidExpression(this.node, this.message);
}
abstract class ErrorReporter {
diff --git a/pkg/front_end/messages.status b/pkg/front_end/messages.status
index 111ca1a..ee438b8 100644
--- a/pkg/front_end/messages.status
+++ b/pkg/front_end/messages.status
@@ -72,6 +72,7 @@
ConstEvalInvalidBinaryOperandType/analyzerCode: Fail # CONST_EVAL_TYPE_NUM / CONST_EVAL_TYPE_BOOL
ConstEvalInvalidBinaryOperandType/example: Fail
ConstEvalInvalidMethodInvocation/example: Fail
+ConstEvalInvalidPropertyGet/example: Fail
ConstEvalInvalidStaticInvocation/example: Fail
ConstEvalInvalidStringInterpolationOperand/example: Fail
ConstEvalInvalidSymbolName/example: Fail
diff --git a/pkg/front_end/messages.yaml b/pkg/front_end/messages.yaml
index 22a299c..d5825f7 100644
--- a/pkg/front_end/messages.yaml
+++ b/pkg/front_end/messages.yaml
@@ -110,6 +110,10 @@
template: "The method '#string' can't be invoked on '#constant' within a const context."
analyzerCode: UNDEFINED_OPERATOR
+ConstEvalInvalidPropertyGet:
+ template: "The property '#string' can't be accessed on '#constant' within a const context."
+ analyzerCode: CONST_EVAL_THROWS_EXCEPTION
+
ConstEvalInvalidStringInterpolationOperand:
template: "The '#constant' can't be used as part of a string interpolation within a const context, only values of type 'null', 'bool', 'int', 'double', or 'String' can be used."
analyzerCode: CONST_EVAL_TYPE_BOOL_NUM_STRING
