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Fix narrowing of dotted names #8390

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Merged
merged 3 commits into from
Apr 29, 2016
Merged

Fix narrowing of dotted names #8390

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bd4923a
Reset dotted name narrowed types when type guards affect base name
ahejlsberg Apr 29, 2016
644e987
Adding regression test
ahejlsberg Apr 29, 2016
ef51195
Removing comments from test
ahejlsberg Apr 29, 2016
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60 changes: 41 additions & 19 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -7335,27 +7335,29 @@ namespace ts {
}

function containsMatchingReference(source: Node, target: Node) {
while (true) {
while (source.kind === SyntaxKind.PropertyAccessExpression) {
source = (<PropertyAccessExpression>source).expression;
if (isMatchingReference(source, target)) {
return true;
}
if (source.kind !== SyntaxKind.PropertyAccessExpression) {
return false;
}
source = (<PropertyAccessExpression>source).expression;
}
return false;
}

function isOrContainsMatchingReference(source: Node, target: Node) {
return isMatchingReference(source, target) || containsMatchingReference(source, target);
}

function hasMatchingArgument(callExpression: CallExpression, target: Node) {
function hasMatchingArgument(callExpression: CallExpression, reference: Node) {
if (callExpression.arguments) {
for (const argument of callExpression.arguments) {
if (isMatchingReference(argument, target)) {
if (isOrContainsMatchingReference(reference, argument)) {
return true;
}
}
}
if (callExpression.expression.kind === SyntaxKind.PropertyAccessExpression &&
isMatchingReference((<PropertyAccessExpression>callExpression.expression).expression, target)) {
isOrContainsMatchingReference(reference, (<PropertyAccessExpression>callExpression.expression).expression)) {
return true;
}
return false;
Expand Down Expand Up @@ -7618,8 +7620,7 @@ namespace ts {
// may be an assignment to a left hand part of the reference. For example, for a
// reference 'x.y.z', we may be at an assignment to 'x.y' or 'x'. In that case,
// return the declared type.
if (reference.kind === SyntaxKind.PropertyAccessExpression &&
containsMatchingReference((<PropertyAccessExpression>reference).expression, node)) {
if (containsMatchingReference(reference, node)) {
return declaredType;
}
// Assignment doesn't affect reference
Expand Down Expand Up @@ -7682,7 +7683,7 @@ namespace ts {
}

function narrowTypeByTruthiness(type: Type, expr: Expression, assumeTrue: boolean): Type {
return isMatchingReference(expr, reference) ? getTypeWithFacts(type, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy) : type;
return isMatchingReference(reference, expr) ? getTypeWithFacts(type, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy) : type;
}

function narrowTypeByBinaryExpression(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
Expand Down Expand Up @@ -7714,7 +7715,7 @@ namespace ts {
if (operator === SyntaxKind.ExclamationEqualsToken || operator === SyntaxKind.ExclamationEqualsEqualsToken) {
assumeTrue = !assumeTrue;
}
if (!strictNullChecks || !isMatchingReference(expr.left, reference)) {
if (!strictNullChecks || !isMatchingReference(reference, expr.left)) {
return type;
}
const doubleEquals = operator === SyntaxKind.EqualsEqualsToken || operator === SyntaxKind.ExclamationEqualsToken;
Expand All @@ -7731,7 +7732,12 @@ namespace ts {
// and string literal on the right
const left = <TypeOfExpression>expr.left;
const right = <LiteralExpression>expr.right;
if (!isMatchingReference(left.expression, reference)) {
if (!isMatchingReference(reference, left.expression)) {
// For a reference of the form 'x.y', a 'typeof x === ...' type guard resets the
// narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, left.expression)) {
return declaredType;
}
return type;
}
if (expr.operatorToken.kind === SyntaxKind.ExclamationEqualsToken ||
Expand All @@ -7754,8 +7760,16 @@ namespace ts {
}

function narrowTypeByInstanceof(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
// Check that type is not any, assumed result is true, and we have variable symbol on the left
if (isTypeAny(type) || !isMatchingReference(expr.left, reference)) {
if (!isMatchingReference(reference, expr.left)) {
// For a reference of the form 'x.y', an 'x instanceof T' type guard resets the
// narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, expr.left)) {
return declaredType;
}
return type;
}
// We never narrow type any in an instanceof guard
if (isTypeAny(type)) {
return type;
}

Expand Down Expand Up @@ -7830,18 +7844,26 @@ namespace ts {
}
if (isIdentifierTypePredicate(predicate)) {
const predicateArgument = callExpression.arguments[predicate.parameterIndex];
if (predicateArgument && isMatchingReference(predicateArgument, reference)) {
return getNarrowedType(type, predicate.type, assumeTrue);
if (predicateArgument) {
if (isMatchingReference(reference, predicateArgument)) {
return getNarrowedType(type, predicate.type, assumeTrue);
}
if (containsMatchingReference(reference, predicateArgument)) {
return declaredType;
}
}
}
else {
const invokedExpression = skipParenthesizedNodes(callExpression.expression);
if (invokedExpression.kind === SyntaxKind.ElementAccessExpression || invokedExpression.kind === SyntaxKind.PropertyAccessExpression) {
const accessExpression = invokedExpression as ElementAccessExpression | PropertyAccessExpression;
const possibleReference= skipParenthesizedNodes(accessExpression.expression);
if (isMatchingReference(possibleReference, reference)) {
const possibleReference = skipParenthesizedNodes(accessExpression.expression);
if (isMatchingReference(reference, possibleReference)) {
return getNarrowedType(type, predicate.type, assumeTrue);
}
if (containsMatchingReference(reference, possibleReference)) {
return declaredType;
}
}
}
return type;
Expand Down
80 changes: 80 additions & 0 deletions tests/baselines/reference/narrowingOfDottedNames.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,80 @@
//// [narrowingOfDottedNames.ts]
// Repro from #8383

class A {
prop: { a: string; };
}

class B {
prop: { b: string; }
}

function isA(x: any): x is A {
return x instanceof A;
}

function isB(x: any): x is B {
return x instanceof B;
}

function f1(x: A | B) {
while (true) {
if (x instanceof A) {
x.prop.a;
}
else if (x instanceof B) {
x.prop.b;
}
}
}

function f2(x: A | B) {
while (true) {
if (isA(x)) {
x.prop.a;
}
else if (isB(x)) {
x.prop.b;
}
}
}


//// [narrowingOfDottedNames.js]
// Repro from #8383
var A = (function () {
function A() {
}
return A;
}());
var B = (function () {
function B() {
}
return B;
}());
function isA(x) {
return x instanceof A;
}
function isB(x) {
return x instanceof B;
}
function f1(x) {
while (true) {
if (x instanceof A) {
x.prop.a;
}
else if (x instanceof B) {
x.prop.b;
}
}
}
function f2(x) {
while (true) {
if (isA(x)) {
x.prop.a;
}
else if (isB(x)) {
x.prop.b;
}
}
}
105 changes: 105 additions & 0 deletions tests/baselines/reference/narrowingOfDottedNames.symbols
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Original file line number Diff line number Diff line change
@@ -0,0 +1,105 @@
=== tests/cases/compiler/narrowingOfDottedNames.ts ===
// Repro from #8383

class A {
>A : Symbol(A, Decl(narrowingOfDottedNames.ts, 0, 0))

prop: { a: string; };
>prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
}

class B {
>B : Symbol(B, Decl(narrowingOfDottedNames.ts, 4, 1))

prop: { b: string; }
>prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
}

function isA(x: any): x is A {
>isA : Symbol(isA, Decl(narrowingOfDottedNames.ts, 8, 1))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 10, 13))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 10, 13))
>A : Symbol(A, Decl(narrowingOfDottedNames.ts, 0, 0))

return x instanceof A;
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 10, 13))
>A : Symbol(A, Decl(narrowingOfDottedNames.ts, 0, 0))
}

function isB(x: any): x is B {
>isB : Symbol(isB, Decl(narrowingOfDottedNames.ts, 12, 1))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 14, 13))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 14, 13))
>B : Symbol(B, Decl(narrowingOfDottedNames.ts, 4, 1))

return x instanceof B;
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 14, 13))
>B : Symbol(B, Decl(narrowingOfDottedNames.ts, 4, 1))
}

function f1(x: A | B) {
>f1 : Symbol(f1, Decl(narrowingOfDottedNames.ts, 16, 1))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 18, 12))
>A : Symbol(A, Decl(narrowingOfDottedNames.ts, 0, 0))
>B : Symbol(B, Decl(narrowingOfDottedNames.ts, 4, 1))

while (true) {
if (x instanceof A) {
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 18, 12))
>A : Symbol(A, Decl(narrowingOfDottedNames.ts, 0, 0))

x.prop.a;
>x.prop.a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
>x.prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 18, 12))
>prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
}
else if (x instanceof B) {
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 18, 12))
>B : Symbol(B, Decl(narrowingOfDottedNames.ts, 4, 1))

x.prop.b;
>x.prop.b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
>x.prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 18, 12))
>prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
}
}
}

function f2(x: A | B) {
>f2 : Symbol(f2, Decl(narrowingOfDottedNames.ts, 27, 1))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))
>A : Symbol(A, Decl(narrowingOfDottedNames.ts, 0, 0))
>B : Symbol(B, Decl(narrowingOfDottedNames.ts, 4, 1))

while (true) {
if (isA(x)) {
>isA : Symbol(isA, Decl(narrowingOfDottedNames.ts, 8, 1))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))

x.prop.a;
>x.prop.a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
>x.prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))
>prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
}
else if (isB(x)) {
>isB : Symbol(isB, Decl(narrowingOfDottedNames.ts, 12, 1))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))

x.prop.b;
>x.prop.b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
>x.prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))
>prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
}
}
}

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