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Merge pull request #10357 from Microsoft/implicitConstParameters

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Implicit const parameters
This commit is contained in:
Anders Hejlsberg
2016-08-16 15:53:13 -07:00
committed by GitHub
parent 01aaff7247 5770157504
commit 905957d463
5 changed files with 311 additions and 30 deletions
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93
src/compiler/checker.ts
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@@ -531,7 +531,7 @@ namespace ts {
function getNodeLinks(node: Node): NodeLinks {
const nodeId = getNodeId(node);
return nodeLinks[nodeId] || (nodeLinks[nodeId] = {});
return nodeLinks[nodeId] || (nodeLinks[nodeId] = { flags: 0 });
}
function isGlobalSourceFile(node: Node) {
@@ -8192,7 +8192,7 @@ namespace ts {
return incomplete ? { flags: 0, type } : type;
}
function getFlowTypeOfReference(reference: Node, declaredType: Type, assumeInitialized: boolean, includeOuterFunctions: boolean) {
function getFlowTypeOfReference(reference: Node, declaredType: Type, assumeInitialized: boolean, flowContainer: Node) {
let key: string;
if (!reference.flowNode || assumeInitialized && !(declaredType.flags & TypeFlags.Narrowable)) {
return declaredType;
@@ -8244,7 +8244,7 @@ namespace ts {
else if (flow.flags & FlowFlags.Start) {
// Check if we should continue with the control flow of the containing function.
const container = (<FlowStart>flow).container;
if (container && includeOuterFunctions) {
if (container && container !== flowContainer && reference.kind !== SyntaxKind.PropertyAccessExpression) {
flow = container.flowNode;
continue;
}
@@ -8722,21 +8722,52 @@ namespace ts {
function getControlFlowContainer(node: Node): Node {
while (true) {
node = node.parent;
if (isFunctionLike(node) || node.kind === SyntaxKind.ModuleBlock || node.kind === SyntaxKind.SourceFile || node.kind === SyntaxKind.PropertyDeclaration) {
if (isFunctionLike(node) && !getImmediatelyInvokedFunctionExpression(node) ||
node.kind === SyntaxKind.ModuleBlock ||
node.kind === SyntaxKind.SourceFile ||
node.kind === SyntaxKind.PropertyDeclaration) {
return node;
}
}
}
function isDeclarationIncludedInFlow(reference: Node, declaration: Declaration, includeOuterFunctions: boolean) {
const declarationContainer = getControlFlowContainer(declaration);
let container = getControlFlowContainer(reference);
while (container !== declarationContainer &&
(container.kind === SyntaxKind.FunctionExpression || container.kind === SyntaxKind.ArrowFunction) &&
(includeOuterFunctions || getImmediatelyInvokedFunctionExpression(<FunctionExpression>container))) {
container = getControlFlowContainer(container);
// Check if a parameter is assigned anywhere within its declaring function.
function isParameterAssigned(symbol: Symbol) {
const func = <FunctionLikeDeclaration>getRootDeclaration(symbol.valueDeclaration).parent;
const links = getNodeLinks(func);
if (!(links.flags & NodeCheckFlags.AssignmentsMarked)) {
links.flags |= NodeCheckFlags.AssignmentsMarked;
if (!hasParentWithAssignmentsMarked(func)) {
markParameterAssignments(func);
}
}
return symbol.isAssigned || false;
}
function hasParentWithAssignmentsMarked(node: Node) {
while (true) {
node = node.parent;
if (!node) {
return false;
}
if (isFunctionLike(node) && getNodeLinks(node).flags & NodeCheckFlags.AssignmentsMarked) {
return true;
}
}
}
function markParameterAssignments(node: Node) {
if (node.kind === SyntaxKind.Identifier) {
if (isAssignmentTarget(node)) {
const symbol = getResolvedSymbol(<Identifier>node);
if (symbol.valueDeclaration && getRootDeclaration(symbol.valueDeclaration).kind === SyntaxKind.Parameter) {
symbol.isAssigned = true;
}
}
}
else {
forEachChild(node, markParameterAssignments);
}
return container === declarationContainer;
}
function checkIdentifier(node: Identifier): Type {
@@ -8791,15 +8822,35 @@ namespace ts {
checkNestedBlockScopedBinding(node, symbol);
const type = getTypeOfSymbol(localOrExportSymbol);
if (!(localOrExportSymbol.flags & SymbolFlags.Variable) || isAssignmentTarget(node)) {
const declaration = localOrExportSymbol.valueDeclaration;
// We only narrow variables and parameters occurring in a non-assignment position. For all other
// entities we simply return the declared type.
if (!(localOrExportSymbol.flags & SymbolFlags.Variable) || isAssignmentTarget(node) || !declaration) {
return type;
}
const declaration = localOrExportSymbol.valueDeclaration;
const includeOuterFunctions = isReadonlySymbol(localOrExportSymbol);
const assumeInitialized = !strictNullChecks || (type.flags & TypeFlags.Any) !== 0 || !declaration ||
getRootDeclaration(declaration).kind === SyntaxKind.Parameter || isInAmbientContext(declaration) ||
!isDeclarationIncludedInFlow(node, declaration, includeOuterFunctions);
const flowType = getFlowTypeOfReference(node, type, assumeInitialized, includeOuterFunctions);
// The declaration container is the innermost function that encloses the declaration of the variable
// or parameter. The flow container is the innermost function starting with which we analyze the control
// flow graph to determine the control flow based type.
const isParameter = getRootDeclaration(declaration).kind === SyntaxKind.Parameter;
const declarationContainer = getControlFlowContainer(declaration);
let flowContainer = getControlFlowContainer(node);
// When the control flow originates in a function expression or arrow function and we are referencing
// a const variable or parameter from an outer function, we extend the origin of the control flow
// analysis to include the immediately enclosing function.
while (flowContainer !== declarationContainer &&
(flowContainer.kind === SyntaxKind.FunctionExpression || flowContainer.kind === SyntaxKind.ArrowFunction) &&
(isReadonlySymbol(localOrExportSymbol) || isParameter && !isParameterAssigned(localOrExportSymbol))) {
flowContainer = getControlFlowContainer(flowContainer);
}
// We only look for uninitialized variables in strict null checking mode, and only when we can analyze
// the entire control flow graph from the variable's declaration (i.e. when the flow container and
// declaration container are the same).
const assumeInitialized = !strictNullChecks || (type.flags & TypeFlags.Any) !== 0 || isParameter ||
flowContainer !== declarationContainer || isInAmbientContext(declaration);
const flowType = getFlowTypeOfReference(node, type, assumeInitialized, flowContainer);
// A variable is considered uninitialized when it is possible to analyze the entire control flow graph
// from declaration to use, and when the variable's declared type doesn't include undefined but the
// control flow based type does include undefined.
if (!assumeInitialized && !(getFalsyFlags(type) & TypeFlags.Undefined) && getFalsyFlags(flowType) & TypeFlags.Undefined) {
error(node, Diagnostics.Variable_0_is_used_before_being_assigned, symbolToString(symbol));
// Return the declared type to reduce follow-on errors
@@ -9052,7 +9103,7 @@ namespace ts {
if (isClassLike(container.parent)) {
const symbol = getSymbolOfNode(container.parent);
const type = container.flags & NodeFlags.Static ? getTypeOfSymbol(symbol) : (<InterfaceType>getDeclaredTypeOfSymbol(symbol)).thisType;
return getFlowTypeOfReference(node, type, /*assumeInitialized*/ true, /*includeOuterFunctions*/ true);
return getFlowTypeOfReference(node, type, /*assumeInitialized*/ true, /*flowContainer*/ undefined);
}
if (isInJavaScriptFile(node)) {
@@ -10717,7 +10768,7 @@ namespace ts {
!(prop.flags & SymbolFlags.Method && propType.flags & TypeFlags.Union)) {
return propType;
}
return getFlowTypeOfReference(node, propType, /*assumeInitialized*/ true, /*includeOuterFunctions*/ false);
return getFlowTypeOfReference(node, propType, /*assumeInitialized*/ true, /*flowContainer*/ undefined);
}
function isValidPropertyAccess(node: PropertyAccessExpression | QualifiedName, propertyName: string): boolean {

20
src/compiler/types.ts
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@@ -2157,6 +2157,7 @@ namespace ts {
/* @internal */ exportSymbol?: Symbol; // Exported symbol associated with this symbol
/* @internal */ constEnumOnlyModule?: boolean; // True if module contains only const enums or other modules with only const enums
/* @internal */ isReferenced?: boolean; // True if the symbol is referenced elsewhere
/* @internal */ isAssigned?: boolean; // True if the symbol is a parameter with assignments
}
/* @internal */
@@ -2209,23 +2210,24 @@ namespace ts {
AsyncMethodWithSuper = 0x00000800, // An async method that reads a value from a member of 'super'.
AsyncMethodWithSuperBinding = 0x00001000, // An async method that assigns a value to a member of 'super'.
CaptureArguments = 0x00002000, // Lexical 'arguments' used in body (for async functions)
EnumValuesComputed = 0x00004000, // Values for enum members have been computed, and any errors have been reported for them.
LexicalModuleMergesWithClass = 0x00008000, // Instantiated lexical module declaration is merged with a previous class declaration.
LoopWithCapturedBlockScopedBinding = 0x00010000, // Loop that contains block scoped variable captured in closure
CapturedBlockScopedBinding = 0x00020000, // Block-scoped binding that is captured in some function
BlockScopedBindingInLoop = 0x00040000, // Block-scoped binding with declaration nested inside iteration statement
ClassWithBodyScopedClassBinding = 0x00080000, // Decorated class that contains a binding to itself inside of the class body.
BodyScopedClassBinding = 0x00100000, // Binding to a decorated class inside of the class's body.
NeedsLoopOutParameter = 0x00200000, // Block scoped binding whose value should be explicitly copied outside of the converted loop
EnumValuesComputed = 0x00004000, // Values for enum members have been computed, and any errors have been reported for them.
LexicalModuleMergesWithClass = 0x00008000, // Instantiated lexical module declaration is merged with a previous class declaration.
LoopWithCapturedBlockScopedBinding = 0x00010000, // Loop that contains block scoped variable captured in closure
CapturedBlockScopedBinding = 0x00020000, // Block-scoped binding that is captured in some function
BlockScopedBindingInLoop = 0x00040000, // Block-scoped binding with declaration nested inside iteration statement
ClassWithBodyScopedClassBinding = 0x00080000, // Decorated class that contains a binding to itself inside of the class body.
BodyScopedClassBinding = 0x00100000, // Binding to a decorated class inside of the class's body.
NeedsLoopOutParameter = 0x00200000, // Block scoped binding whose value should be explicitly copied outside of the converted loop
AssignmentsMarked = 0x00400000, // Parameter assignments have been marked
}
/* @internal */
export interface NodeLinks {
flags?: NodeCheckFlags; // Set of flags specific to Node
resolvedType?: Type; // Cached type of type node
resolvedSignature?: Signature; // Cached signature of signature node or call expression
resolvedSymbol?: Symbol; // Cached name resolution result
resolvedIndexInfo?: IndexInfo; // Cached indexing info resolution result
flags?: NodeCheckFlags; // Set of flags specific to Node
enumMemberValue?: number; // Constant value of enum member
isVisible?: boolean; // Is this node visible
hasReportedStatementInAmbientContext?: boolean; // Cache boolean if we report statements in ambient context

65
tests/baselines/reference/implicitConstParameters.errors.txt Normal file
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@@ -0,0 +1,65 @@
tests/cases/compiler/implicitConstParameters.ts(39,27): error TS2532: Object is possibly 'undefined'.
tests/cases/compiler/implicitConstParameters.ts(45,27): error TS2532: Object is possibly 'undefined'.
==== tests/cases/compiler/implicitConstParameters.ts (2 errors) ====
function doSomething(cb: () => void) {
cb();
}
function fn(x: number | string) {
if (typeof x === 'number') {
doSomething(() => x.toFixed());
}
}
function f1(x: string | undefined) {
if (!x) {
return;
}
doSomething(() => x.length);
}
function f2(x: string | undefined) {
if (x) {
doSomething(() => {
doSomething(() => x.length);
});
}
}
function f3(x: string | undefined) {
inner();
function inner() {
if (x) {
doSomething(() => x.length);
}
}
}
function f4(x: string | undefined) {
x = "abc"; // causes x to be considered non-const
if (x) {
doSomething(() => x.length);
~
!!! error TS2532: Object is possibly 'undefined'.
}
}
function f5(x: string | undefined) {
if (x) {
doSomething(() => x.length);
~
!!! error TS2532: Object is possibly 'undefined'.
}
x = "abc"; // causes x to be considered non-const
}
function f6(x: string | undefined) {
const y = x || "";
if (x) {
doSomething(() => y.length);
}
}

106
tests/baselines/reference/implicitConstParameters.js Normal file
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@@ -0,0 +1,106 @@
//// [implicitConstParameters.ts]
function doSomething(cb: () => void) {
cb();
}
function fn(x: number | string) {
if (typeof x === 'number') {
doSomething(() => x.toFixed());
}
}
function f1(x: string | undefined) {
if (!x) {
return;
}
doSomething(() => x.length);
}
function f2(x: string | undefined) {
if (x) {
doSomething(() => {
doSomething(() => x.length);
});
}
}
function f3(x: string | undefined) {
inner();
function inner() {
if (x) {
doSomething(() => x.length);
}
}
}
function f4(x: string | undefined) {
x = "abc"; // causes x to be considered non-const
if (x) {
doSomething(() => x.length);
}
}
function f5(x: string | undefined) {
if (x) {
doSomething(() => x.length);
}
x = "abc"; // causes x to be considered non-const
}
function f6(x: string | undefined) {
const y = x || "";
if (x) {
doSomething(() => y.length);
}
}
//// [implicitConstParameters.js]
function doSomething(cb) {
cb();
}
function fn(x) {
if (typeof x === 'number') {
doSomething(function () { return x.toFixed(); });
}
}
function f1(x) {
if (!x) {
return;
}
doSomething(function () { return x.length; });
}
function f2(x) {
if (x) {
doSomething(function () {
doSomething(function () { return x.length; });
});
}
}
function f3(x) {
inner();
function inner() {
if (x) {
doSomething(function () { return x.length; });
}
}
}
function f4(x) {
x = "abc"; // causes x to be considered non-const
if (x) {
doSomething(function () { return x.length; });
}
}
function f5(x) {
if (x) {
doSomething(function () { return x.length; });
}
x = "abc"; // causes x to be considered non-const
}
function f6(x) {
var y = x || "";
if (x) {
doSomething(function () { return y.length; });
}
}

57
tests/cases/compiler/implicitConstParameters.ts Normal file
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@@ -0,0 +1,57 @@
// @strictNullChecks: true
function doSomething(cb: () => void) {
cb();
}
function fn(x: number | string) {
if (typeof x === 'number') {
doSomething(() => x.toFixed());
}
}
function f1(x: string | undefined) {
if (!x) {
return;
}
doSomething(() => x.length);
}
function f2(x: string | undefined) {
if (x) {
doSomething(() => {
doSomething(() => x.length);
});
}
}
function f3(x: string | undefined) {
inner();
function inner() {
if (x) {
doSomething(() => x.length);
}
}
}
function f4(x: string | undefined) {
x = "abc"; // causes x to be considered non-const
if (x) {
doSomething(() => x.length);
}
}
function f5(x: string | undefined) {
if (x) {
doSomething(() => x.length);
}
x = "abc"; // causes x to be considered non-const
}
function f6(x: string | undefined) {
const y = x || "";
if (x) {
doSomething(() => y.length);
}
}