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Infer return types from yield and yield* expressions

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This commit is contained in:
Jason Freeman 2015-04-28 17:48:32 -07:00
parent 44777b9737
commit 7fce775149
4 changed files with 185 additions and 93 deletions
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139
src/compiler/checker.ts
View File

@ -7260,16 +7260,35 @@ module ts {
}
else {
// Aggregate the types of expressions within all the return statements.
let types = checkAndAggregateReturnExpressionTypes(<Block>func.body, contextualMapper);
if (types.length === 0) {
return voidType;
let types: Type[];
if (func.asteriskToken) {
types = checkAndAggregateYieldOperandTypes(<Block>func.body, contextualMapper);
if (types.length === 0) {
return createIterableIteratorType(anyType);
}
}
else {
types = checkAndAggregateReturnExpressionTypes(<Block>func.body, contextualMapper);
if (types.length === 0) {
return voidType;
}
}
// When return statements are contextually typed we allow the return type to be a union type. Otherwise we require the
// return expressions to have a best common supertype.
type = contextualSignature ? getUnionType(types) : getCommonSupertype(types);
if (!type) {
error(func, Diagnostics.No_best_common_type_exists_among_return_expressions);
return unknownType;
if (func.asteriskToken) {
error(func, Diagnostics.No_best_common_type_exists_among_yield_expressions);
return createIterableIteratorType(unknownType);
}
else {
error(func, Diagnostics.No_best_common_type_exists_among_return_expressions);
return unknownType;
}
}
if (func.asteriskToken) {
type = createIterableIteratorType(type);
}
}
if (!contextualSignature) {
@ -7278,7 +7297,28 @@ module ts {
return getWidenedType(type);
}
/// Returns a set of types relating to every return expression relating to a function block.
function checkAndAggregateYieldOperandTypes(body: Block, contextualMapper?: TypeMapper): Type[] {
let aggregatedTypes: Type[] = [];
forEachYieldExpression(body, yieldExpression => {
let expr = yieldExpression.expression;
if (expr) {
let type = checkExpressionCached(expr, contextualMapper);
if (yieldExpression.asteriskToken) {
// A yield* expression effectively yields everything that its operand yields
type = checkIteratedType(type, yieldExpression.expression);
}
if (!contains(aggregatedTypes, type)) {
aggregatedTypes.push(type);
}
}
});
return aggregatedTypes;
}
function checkAndAggregateReturnExpressionTypes(body: Block, contextualMapper?: TypeMapper): Type[] {
let aggregatedTypes: Type[] = [];
@ -11253,93 +11293,6 @@ module ts {
return node.parent && node.parent.kind === SyntaxKind.ExpressionWithTypeArguments;
}
function isTypeNode(node: Node): boolean {
if (SyntaxKind.FirstTypeNode <= node.kind && node.kind <= SyntaxKind.LastTypeNode) {
return true;
}
switch (node.kind) {
case SyntaxKind.AnyKeyword:
case SyntaxKind.NumberKeyword:
case SyntaxKind.StringKeyword:
case SyntaxKind.BooleanKeyword:
case SyntaxKind.SymbolKeyword:
return true;
case SyntaxKind.VoidKeyword:
return node.parent.kind !== SyntaxKind.VoidExpression;
case SyntaxKind.StringLiteral:
// Specialized signatures can have string literals as their parameters' type names
return node.parent.kind === SyntaxKind.Parameter;
case SyntaxKind.ExpressionWithTypeArguments:
return true;
// Identifiers and qualified names may be type nodes, depending on their context. Climb
// above them to find the lowest container
case SyntaxKind.Identifier:
// If the identifier is the RHS of a qualified name, then it's a type iff its parent is.
if (node.parent.kind === SyntaxKind.QualifiedName && (<QualifiedName>node.parent).right === node) {
node = node.parent;
}
else if (node.parent.kind === SyntaxKind.PropertyAccessExpression && (<PropertyAccessExpression>node.parent).name === node) {
node = node.parent;
}
// fall through
case SyntaxKind.QualifiedName:
case SyntaxKind.PropertyAccessExpression:
// At this point, node is either a qualified name or an identifier
Debug.assert(node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.QualifiedName || node.kind === SyntaxKind.PropertyAccessExpression,
"'node' was expected to be a qualified name, identifier or property access in 'isTypeNode'.");
let parent = node.parent;
if (parent.kind === SyntaxKind.TypeQuery) {
return false;
}
// Do not recursively call isTypeNode on the parent. In the example:
//
// let a: A.B.C;
//
// Calling isTypeNode would consider the qualified name A.B a type node. Only C or
// A.B.C is a type node.
if (SyntaxKind.FirstTypeNode <= parent.kind && parent.kind <= SyntaxKind.LastTypeNode) {
return true;
}
switch (parent.kind) {
case SyntaxKind.ExpressionWithTypeArguments:
return true;
case SyntaxKind.TypeParameter:
return node === (<TypeParameterDeclaration>parent).constraint;
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
case SyntaxKind.Parameter:
case SyntaxKind.VariableDeclaration:
return node === (<VariableLikeDeclaration>parent).type;
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
case SyntaxKind.Constructor:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
return node === (<FunctionLikeDeclaration>parent).type;
case SyntaxKind.CallSignature:
case SyntaxKind.ConstructSignature:
case SyntaxKind.IndexSignature:
return node === (<SignatureDeclaration>parent).type;
case SyntaxKind.TypeAssertionExpression:
return node === (<TypeAssertion>parent).type;
case SyntaxKind.CallExpression:
case SyntaxKind.NewExpression:
return (<CallExpression>parent).typeArguments && indexOf((<CallExpression>parent).typeArguments, node) >= 0;
case SyntaxKind.TaggedTemplateExpression:
// TODO (drosen): TaggedTemplateExpressions may eventually support type arguments.
return false;
}
}
return false;
}
function getLeftSideOfImportEqualsOrExportAssignment(nodeOnRightSide: EntityName): ImportEqualsDeclaration | ExportAssignment {
while (nodeOnRightSide.parent.kind === SyntaxKind.QualifiedName) {
nodeOnRightSide = <QualifiedName>nodeOnRightSide.parent;

1
src/compiler/diagnosticInformationMap.generated.ts
View File

@ -367,6 +367,7 @@ module ts {
A_class_can_only_implement_an_identifier_Slashqualified_name_with_optional_type_arguments: { code: 2500, category: DiagnosticCategory.Error, key: "A class can only implement an identifier/qualified-name with optional type arguments." },
A_rest_element_cannot_contain_a_binding_pattern: { code: 2501, category: DiagnosticCategory.Error, key: "A rest element cannot contain a binding pattern." },
A_return_statement_cannot_specify_a_value_in_a_generator_function: { code: 2502, category: DiagnosticCategory.Error, key: "A return statement cannot specify a value in a generator function." },
No_best_common_type_exists_among_yield_expressions: { code: 2503, category: DiagnosticCategory.Error, key: "No best common type exists among yield expressions." },
Import_declaration_0_is_using_private_name_1: { code: 4000, category: DiagnosticCategory.Error, key: "Import declaration '{0}' is using private name '{1}'." },
Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: { code: 4002, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported class has or is using private name '{1}'." },
Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: { code: 4004, category: DiagnosticCategory.Error, key: "Type parameter '{0}' of exported interface has or is using private name '{1}'." },

4
src/compiler/diagnosticMessages.json
View File

@ -1457,6 +1457,10 @@
"category": "Error",
"code": 2502
},
"No best common type exists among yield expressions.": {
"category": "Error",
"code": 2503
},
"Import declaration '{0}' is using private name '{1}'.": {
"category": "Error",

134
src/compiler/utilities.ts
View File

@ -408,6 +408,93 @@ module ts {
export let fullTripleSlashReferencePathRegEx = /^(\/\/\/\s*<reference\s+path\s*=\s*)('|")(.+?)\2.*?\/>/
export function isTypeNode(node: Node): boolean {
if (SyntaxKind.FirstTypeNode <= node.kind && node.kind <= SyntaxKind.LastTypeNode) {
return true;
}
switch (node.kind) {
case SyntaxKind.AnyKeyword:
case SyntaxKind.NumberKeyword:
case SyntaxKind.StringKeyword:
case SyntaxKind.BooleanKeyword:
case SyntaxKind.SymbolKeyword:
return true;
case SyntaxKind.VoidKeyword:
return node.parent.kind !== SyntaxKind.VoidExpression;
case SyntaxKind.StringLiteral:
// Specialized signatures can have string literals as their parameters' type names
return node.parent.kind === SyntaxKind.Parameter;
case SyntaxKind.ExpressionWithTypeArguments:
return true;
// Identifiers and qualified names may be type nodes, depending on their context. Climb
// above them to find the lowest container
case SyntaxKind.Identifier:
// If the identifier is the RHS of a qualified name, then it's a type iff its parent is.
if (node.parent.kind === SyntaxKind.QualifiedName && (<QualifiedName>node.parent).right === node) {
node = node.parent;
}
else if (node.parent.kind === SyntaxKind.PropertyAccessExpression && (<PropertyAccessExpression>node.parent).name === node) {
node = node.parent;
}
// fall through
case SyntaxKind.QualifiedName:
case SyntaxKind.PropertyAccessExpression:
// At this point, node is either a qualified name or an identifier
Debug.assert(node.kind === SyntaxKind.Identifier || node.kind === SyntaxKind.QualifiedName || node.kind === SyntaxKind.PropertyAccessExpression,
"'node' was expected to be a qualified name, identifier or property access in 'isTypeNode'.");
let parent = node.parent;
if (parent.kind === SyntaxKind.TypeQuery) {
return false;
}
// Do not recursively call isTypeNode on the parent. In the example:
//
// let a: A.B.C;
//
// Calling isTypeNode would consider the qualified name A.B a type node. Only C or
// A.B.C is a type node.
if (SyntaxKind.FirstTypeNode <= parent.kind && parent.kind <= SyntaxKind.LastTypeNode) {
return true;
}
switch (parent.kind) {
case SyntaxKind.ExpressionWithTypeArguments:
return true;
case SyntaxKind.TypeParameter:
return node === (<TypeParameterDeclaration>parent).constraint;
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
case SyntaxKind.Parameter:
case SyntaxKind.VariableDeclaration:
return node === (<VariableLikeDeclaration>parent).type;
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.FunctionExpression:
case SyntaxKind.ArrowFunction:
case SyntaxKind.Constructor:
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
return node === (<FunctionLikeDeclaration>parent).type;
case SyntaxKind.CallSignature:
case SyntaxKind.ConstructSignature:
case SyntaxKind.IndexSignature:
return node === (<SignatureDeclaration>parent).type;
case SyntaxKind.TypeAssertionExpression:
return node === (<TypeAssertion>parent).type;
case SyntaxKind.CallExpression:
case SyntaxKind.NewExpression:
return (<CallExpression>parent).typeArguments && indexOf((<CallExpression>parent).typeArguments, node) >= 0;
case SyntaxKind.TaggedTemplateExpression:
// TODO (drosen): TaggedTemplateExpressions may eventually support type arguments.
return false;
}
}
return false;
}
// Warning: This has the same semantics as the forEach family of functions,
// in that traversal terminates in the event that 'visitor' supplies a truthy value.
export function forEachReturnStatement<T>(body: Block, visitor: (stmt: ReturnStatement) => T): T {
@ -438,6 +525,52 @@ module ts {
}
}
export function forEachYieldExpression(body: Block, visitor: (expr: YieldExpression) => void): void {
return traverse(body);
function traverse(node: Node): void {
// Yield expressions may occur in decorators
if (node.decorators) {
forEach(node.decorators, traverse);
}
switch (node.kind) {
case SyntaxKind.YieldExpression:
visitor(<YieldExpression>node);
let operand = (<YieldExpression>node).expression;
if (operand) {
traverse(operand);
}
case SyntaxKind.EnumDeclaration:
case SyntaxKind.InterfaceDeclaration:
case SyntaxKind.ModuleDeclaration:
case SyntaxKind.TypeAliasDeclaration:
// These are not allowed inside a generator now, but eventually they may be allowed
// as local types. Regardless, any yield statements contained within them should be
// skipped in this traversal.
return;
case SyntaxKind.ClassDeclaration:
// A class declaration/expression may extend a yield expression
forEach((<ClassDeclaration>node).heritageClauses, traverse);
return;
default:
if (isFunctionLike(node)) {
let name = (<FunctionLikeDeclaration>node).name;
if (name && name.kind === SyntaxKind.ComputedPropertyName) {
traverse((<ComputedPropertyName>name).expression);
return;
}
}
else if (!isTypeNode(node)) {
// This is the general case, which should include mostly expressions and statements.
// Also includes NodeArrays.
forEachChild(node, traverse);
}
}
}
}
export function isVariableLike(node: Node): boolean {
if (node) {
switch (node.kind) {
@ -736,6 +869,7 @@ module ts {
case SyntaxKind.TemplateExpression:
case SyntaxKind.NoSubstitutionTemplateLiteral:
case SyntaxKind.OmittedExpression:
case SyntaxKind.YieldExpression:
return true;
case SyntaxKind.QualifiedName:
while (node.parent.kind === SyntaxKind.QualifiedName) {