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Convert ShadowIfNullExpression to IfNullJudgment

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Change-Id: Id61c657b9eaf0e390e9f75c5ab711323a5212bbb
Reviewed-on: https://dart-review.googlesource.com/61825
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
This commit is contained in:
Paul Berry 2018-06-22 03:06:46 +00:00 committed by commit-bot@chromium.org
parent 7c327c32b7
commit 6fd40725af
3 changed files with 17 additions and 11 deletions
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2
pkg/front_end/lib/src/fasta/kernel/body_builder.dart
View file

@ -1075,7 +1075,7 @@ abstract class BodyBuilder extends ScopeListener<JumpTarget>
Expression b = popForValue();
Expression a = popForValue();
VariableDeclaration variable = new VariableDeclaration.forValue(a);
push(new ShadowIfNullExpression(
push(new IfNullJudgment(
variable,
forest.conditionalExpression(
buildIsNull(new VariableGet(variable), offsetForToken(token), this),

2
pkg/front_end/lib/src/fasta/kernel/kernel_ast_api.dart
View file

@ -79,7 +79,7 @@ export 'kernel_shadow_ast.dart'
ForInJudgment,
ShadowFunctionDeclaration,
ShadowFunctionExpression,
ShadowIfNullExpression,
IfNullJudgment,
IfJudgment,
IllegalAssignmentJudgment,
IndexAssignmentJudgment,

24
pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
View file

@ -1338,42 +1338,48 @@ class ShadowFunctionExpression extends FunctionExpression
/// expression:
///
/// let v = a in v == null ? b : v
class ShadowIfNullExpression extends Let implements ExpressionJudgment {
class IfNullJudgment extends Let implements ExpressionJudgment {
DartType inferredType;
ShadowIfNullExpression(VariableDeclaration variable, Expression body)
IfNullJudgment(VariableDeclaration variable, Expression body)
: super(variable, body);
@override
ConditionalExpression get body => super.body;
/// Returns the expression to the left of `??`.
Expression get _lhs => variable.initializer;
ExpressionJudgment get leftJudgment => variable.initializer;
/// Returns the expression to the right of `??`.
Expression get _rhs => body.then;
ExpressionJudgment get rightJudgment => body.then;
@override
DartType infer<Expression, Statement, Initializer, Type>(
ShadowTypeInferrer inferrer,
Factory<Expression, Statement, Initializer, Type> factory,
DartType typeContext) {
var leftJudgment = this.leftJudgment;
var rightJudgment = this.rightJudgment;
// To infer `e0 ?? e1` in context K:
// - Infer e0 in context K to get T0
var lhsType = inferrer.inferExpression(factory, _lhs, typeContext, true);
inferrer.inferExpression(factory, leftJudgment, typeContext, true);
var lhsType = leftJudgment.inferredType;
if (inferrer.strongMode) {
variable.type = lhsType;
}
// - Let J = T0 if K is `?` else K.
// - Infer e1 in context J to get T1
bool useLub = _forceLub || typeContext is UnknownType;
var rhsType = typeContext is UnknownType
? inferrer.inferExpression(factory, _rhs, lhsType, true)
: inferrer.inferExpression(factory, _rhs, typeContext, _forceLub);
if (typeContext is UnknownType) {
inferrer.inferExpression(factory, rightJudgment, lhsType, true);
} else {
inferrer.inferExpression(factory, rightJudgment, typeContext, _forceLub);
}
var rhsType = rightJudgment.inferredType;
// - Let T = greatest closure of K with respect to `?` if K is not `_`, else
// UP(t0, t1)
// - Then the inferred type is T.
var inferredType = useLub
inferredType = useLub
? inferrer.typeSchemaEnvironment.getLeastUpperBound(lhsType, rhsType)
: greatestClosure(inferrer.coreTypes, typeContext);
if (inferrer.strongMode) {