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Use ParameterMember when substituting function types.
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This ensures that the parameters from the function type still point to
the original function declaration (previously, they were synthetic
parameters).  This should lead to a better user experience in editor
integration, by ensuring that the editor can still find the parameter
declarations associated with parameters in generic function
invocations.

Fixes #48500.

Change-Id: I10a0dd54e7c70e1d0d05dced37565c35bcaabfd0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/243524
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
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@stereotype441
stereotype441 authored and Commit Bot committed May 12, 2022
1 parent e593b86 commit f5af2d9
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Showing 5 changed files with 122 additions and 34 deletions.
87 changes: 65 additions & 22 deletions pkg/analyzer/lib/src/dart/element/member.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ class ConstructorMember extends ExecutableMember
/// Initialize a newly created element to represent a constructor, based on
/// the [declaration], and applied [substitution].
ConstructorMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
ConstructorElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -138,7 +138,7 @@ abstract class ExecutableMember extends Member implements ExecutableElement {
/// their bounds. The [substitution] includes replacing [declaration] type
/// parameters with the provided fresh [typeParameters].
ExecutableMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
ExecutableElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -178,6 +178,12 @@ abstract class ExecutableMember extends Member implements ExecutableElement {
@override
bool get isSynchronous => declaration.isSynchronous;

@override
LibraryElement get library => _declaration.library!;

@override
Source get librarySource => _declaration.librarySource!;

@override
List<ParameterElement> get parameters {
return declaration.parameters.map<ParameterElement>((p) {
Expand Down Expand Up @@ -220,7 +226,7 @@ abstract class ExecutableMember extends Member implements ExecutableElement {
ExecutableElement element,
MapSubstitution substitution,
) {
TypeProviderImpl typeProvider;
TypeProviderImpl? typeProvider;
var isLegacy = false;
var combined = substitution;
if (element is ExecutableMember) {
Expand Down Expand Up @@ -261,7 +267,7 @@ abstract class ExecutableMember extends Member implements ExecutableElement {
class FieldFormalParameterMember extends ParameterMember
implements FieldFormalParameterElement {
factory FieldFormalParameterMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
FieldFormalParameterElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand All @@ -280,7 +286,7 @@ class FieldFormalParameterMember extends ParameterMember
}

FieldFormalParameterMember._(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
FieldFormalParameterElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -320,7 +326,7 @@ class FieldMember extends VariableMember implements FieldElement {
/// Initialize a newly created element to represent a field, based on the
/// [declaration], with applied [substitution].
FieldMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
FieldElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -360,6 +366,9 @@ class FieldMember extends VariableMember implements FieldElement {
@override
bool get isExternal => declaration.isExternal;

@override
LibraryElement get library => _declaration.library!;

@override
String get name => declaration.name;

Expand Down Expand Up @@ -406,8 +415,8 @@ class FieldMember extends VariableMember implements FieldElement {
}

class FunctionMember extends ExecutableMember implements FunctionElement {
FunctionMember(
TypeProviderImpl typeProvider, FunctionElement declaration, bool isLegacy)
FunctionMember(TypeProviderImpl? typeProvider, FunctionElement declaration,
bool isLegacy)
: super(
typeProvider,
declaration,
Expand Down Expand Up @@ -441,7 +450,7 @@ class FunctionMember extends ExecutableMember implements FunctionElement {
/// parameters are known.
abstract class Member implements Element {
/// A type provider (might be legacy, might be null-safe).
final TypeProviderImpl _typeProvider;
final TypeProviderImpl? _typeProvider;

/// The element on which the parameterized element was created.
final Element _declaration;
Expand All @@ -459,6 +468,10 @@ abstract class Member implements Element {
if (_declaration is Member) {
throw StateError('Members must be created from a declarations.');
}
if (_typeProvider == null && isLegacy) {
throw StateError(
'A type provider must be supplied for legacy conversion');
}
}

@override
Expand Down Expand Up @@ -552,10 +565,10 @@ abstract class Member implements Element {
ElementKind get kind => _declaration.kind;

@override
LibraryElement get library => _declaration.library!;
LibraryElement? get library => _declaration.library;

@override
Source get librarySource => _declaration.librarySource!;
Source? get librarySource => _declaration.librarySource;

@override
ElementLocation get location => _declaration.location!;
Expand Down Expand Up @@ -642,7 +655,7 @@ abstract class Member implements Element {
/// Otherwise, return the type unchanged.
DartType _toLegacyType(DartType type) {
if (isLegacy) {
return NullabilityEliminator.perform(_typeProvider, type);
return NullabilityEliminator.perform(_typeProvider!, type);
} else {
return type;
}
Expand Down Expand Up @@ -720,7 +733,7 @@ abstract class Member implements Element {
/// type parameters are known.
class MethodMember extends ExecutableMember implements MethodElement {
factory MethodMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
MethodElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand All @@ -739,7 +752,7 @@ class MethodMember extends ExecutableMember implements MethodElement {
}

MethodMember._(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
MethodElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -799,7 +812,7 @@ class ParameterMember extends VariableMember
final List<TypeParameterElement> typeParameters;

factory ParameterMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
ParameterElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand All @@ -820,7 +833,7 @@ class ParameterMember extends VariableMember
/// Initialize a newly created element to represent a parameter, based on the
/// [declaration], with applied [substitution].
ParameterMember._(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
ParameterElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -887,14 +900,41 @@ class ParameterMember extends VariableMember
super.visitChildren(visitor);
safelyVisitChildren(parameters, visitor);
}

static ParameterElement from(
ParameterElement element, MapSubstitution substitution) {
TypeProviderImpl? typeProvider;
var isLegacy = false;
var combined = substitution;
if (element is ParameterMember) {
var member = element;
element = member.declaration;
typeProvider = member._typeProvider;

isLegacy = member.isLegacy;

var map = <TypeParameterElement, DartType>{};
for (var entry in member._substitution.map.entries) {
map[entry.key] = substitution.substituteType(entry.value);
}
map.addAll(substitution.map);
combined = Substitution.fromMap(map);
}

if (!isLegacy && combined.map.isEmpty) {
return element;
}

return ParameterMember(typeProvider, element, combined, isLegacy);
}
}

/// A property accessor element defined in a parameterized type where the values
/// of the type parameters are known.
class PropertyAccessorMember extends ExecutableMember
implements PropertyAccessorElement {
factory PropertyAccessorMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
PropertyAccessorElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand All @@ -913,7 +953,7 @@ class PropertyAccessorMember extends ExecutableMember
}

PropertyAccessorMember._(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
PropertyAccessorElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -1005,7 +1045,7 @@ class PropertyAccessorMember extends ExecutableMember
class SuperFormalParameterMember extends ParameterMember
implements SuperFormalParameterElement {
factory SuperFormalParameterMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
SuperFormalParameterElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand All @@ -1024,7 +1064,7 @@ class SuperFormalParameterMember extends ParameterMember
}

SuperFormalParameterMember._(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
SuperFormalParameterElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -1063,7 +1103,7 @@ class SuperFormalParameterMember extends ParameterMember
class TopLevelVariableMember extends VariableMember
implements TopLevelVariableElement {
TopLevelVariableMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
VariableElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down Expand Up @@ -1092,6 +1132,9 @@ class TopLevelVariableMember extends VariableMember
@override
bool get isExternal => declaration.isExternal;

@override
LibraryElement get library => _declaration.library!;

@override
String get name => declaration.name;

Expand Down Expand Up @@ -1119,7 +1162,7 @@ abstract class VariableMember extends Member implements VariableElement {
/// Initialize a newly created element to represent a variable, based on the
/// [declaration], with applied [substitution].
VariableMember(
TypeProviderImpl typeProvider,
TypeProviderImpl? typeProvider,
VariableElement declaration,
MapSubstitution substitution,
bool isLegacy,
Expand Down
6 changes: 2 additions & 4 deletions pkg/analyzer/lib/src/dart/element/type.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,6 @@ import 'package:analyzer/dart/element/type_visitor.dart';
import 'package:analyzer/src/dart/analysis/session.dart';
import 'package:analyzer/src/dart/element/display_string_builder.dart';
import 'package:analyzer/src/dart/element/element.dart';
import 'package:analyzer/src/dart/element/extensions.dart';
import 'package:analyzer/src/dart/element/inheritance_manager3.dart';
import 'package:analyzer/src/dart/element/member.dart';
import 'package:analyzer/src/dart/element/type_algebra.dart';
Expand Down Expand Up @@ -224,9 +223,8 @@ class FunctionTypeImpl extends TypeImpl implements FunctionType {
return FunctionTypeImpl(
returnType: substitution.substituteType(returnType),
typeFormals: const [],
parameters: parameters
.map((p) => p.copyWith(type: substitution.substituteType(p.type)))
.toList(),
parameters:
parameters.map((p) => ParameterMember.from(p, substitution)).toList(),
nullabilitySuffix: nullabilitySuffix,
);
}
Expand Down
3 changes: 3 additions & 0 deletions pkg/analyzer/lib/src/test_utilities/mock_sdk.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -591,6 +591,9 @@ abstract class Set<E> implements Iterable<E> {
void addAll(Iterable<E> elements);
bool remove(Object? value);
E? lookup(Object? object);
static Set<T> castFrom<S, T>(Set<S> source, {Set<R> Function<R>()? newSet}) =>
throw '';
}
class StackTrace {}
Expand Down
45 changes: 37 additions & 8 deletions pkg/analyzer/test/generated/non_error_resolver_test.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1458,10 +1458,8 @@ test(C c) => c.method<bool>(arg: true);
''');
var x = findNode.namedExpression('arg: true');
var y = x.staticParameterElement!;
// Note: the staticParameterElement is synthetic; see
// https://github.com/dart-lang/sdk/issues/48500
expect(y, isNot(TypeMatcher<ParameterMember>()));
expect(y.enclosingElement, isNull);
expect(y.enclosingElement, isNotNull);
expect(y.declaration, findElement.parameter('arg'));
}

test_generic_staticParameterElement_methodCall_implicitTypeArg() async {
Expand All @@ -1473,10 +1471,8 @@ bool test(C c) => c.method<bool>(arg: true);
''');
var x = findNode.namedExpression('arg: true');
var y = x.staticParameterElement!;
// Note: the staticParameterElement is synthetic; see
// https://github.com/dart-lang/sdk/issues/48500
expect(y, isNot(TypeMatcher<ParameterMember>()));
expect(y.enclosingElement, isNull);
expect(y.enclosingElement, isNotNull);
expect(y.declaration, findElement.parameter('arg'));
}

test_genericTypeAlias_castsAndTypeChecks_hasTypeParameters() async {
Expand Down Expand Up @@ -2258,6 +2254,21 @@ int f(v) {
''');
}

test_librarySource_of_type_substituted_synthetic_parameter() async {
await assertErrorsInCode('''
Map<int, T> f<T>(T t) => throw '';
Map<double, T> g<T>(T t) => throw '';
h(bool b) {
Map<num, String> m = (b ? f : g)('x');
}
''', [
error(HintCode.UNUSED_LOCAL_VARIABLE, 104, 1),
]);
var parameter = findNode.stringLiteral("'x'").staticParameterElement;
expect(parameter!.library, isNull);
expect(parameter.librarySource, isNull);
}

test_loadLibraryDefined() async {
newFile('$testPackageLibPath/lib.dart', r'''
library lib;
Expand Down Expand Up @@ -3310,6 +3321,24 @@ core.dynamic dynamicVariable;
@reflectiveTest
class NonErrorResolverWithoutNullSafetyTest extends PubPackageResolutionTest
with WithoutNullSafetyMixin, NonErrorResolverTestCases {
test_castFrom() async {
// This test exercises a corner case of legacy erasure: due to the type
// substitution in the `newSet` parameter of `Set.castFrom`, we wind up with
// a synthetic `ParameterMember` that belongs to no library. We need to
// make sure this doesn't lead to a crash.
await assertErrorsInCode('''
class C {}
void testNewSet(Set<C> setEls) {
var customNewSet;
Set.castFrom<C, Object>(setEls,
newSet: <T>() => customNewSet = new Set<T>());
}
''', [
error(HintCode.UNUSED_LOCAL_VARIABLE, 51, 12),
]);
}

test_conflictingStaticGetterAndInstanceSetter_thisClass() async {
await assertNoErrorsInCode(r'''
class A {
Expand Down
15 changes: 15 additions & 0 deletions pkg/analyzer/test/src/dart/resolution/constructor_reference_test.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -242,6 +242,21 @@ ConstructorReference
''');
}

test_alias_generic_with_inferred_type_parameter() async {
await assertErrorsInCode('''
class C<T> {
final T x;
C(this.x);
}
typedef Direct<T> = C<T>;
void main() {
var x = const <C<int> Function(int)>[Direct.new];
}
''', [
error(HintCode.UNUSED_LOCAL_VARIABLE, 87, 1),
]);
}

test_alias_genericWithBound_unnamed() async {
await assertNoErrorsInCode('''
class A<T> {
Expand Down

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