Skip to content

Fix nested loop type guards #10396

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Aug 17, 2016
Merged

Fix nested loop type guards #10396

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
2d1639f
Property handle imcomplete control flow types in nested loops
ahejlsberg Aug 17, 2016
b93cdec
Add regression test
ahejlsberg Aug 17, 2016
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 13 additions & 2 deletions src/compiler/checker.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8364,13 +8364,18 @@ namespace ts {
// each antecedent code path.
const antecedentTypes: Type[] = [];
let subtypeReduction = false;
let firstAntecedentType: FlowType;
flowLoopNodes[flowLoopCount] = flow;
flowLoopKeys[flowLoopCount] = key;
flowLoopTypes[flowLoopCount] = antecedentTypes;
for (const antecedent of flow.antecedents) {
flowLoopCount++;
const type = getTypeFromFlowType(getTypeAtFlowNode(antecedent));
const flowType = getTypeAtFlowNode(antecedent);
flowLoopCount--;
if (!firstAntecedentType) {
firstAntecedentType = flowType;
}
const type = getTypeFromFlowType(flowType);
// If we see a value appear in the cache it is a sign that control flow analysis
// was restarted and completed by checkExpressionCached. We can simply pick up
// the resulting type and bail out.
Expand All @@ -8393,7 +8398,13 @@ namespace ts {
break;
}
}
return cache[key] = getUnionType(antecedentTypes, subtypeReduction);
// The result is incomplete if the first antecedent (the non-looping control flow path)
// is incomplete.
const result = getUnionType(antecedentTypes, subtypeReduction);
if (isIncomplete(firstAntecedentType)) {
return createFlowType(result, /*incomplete*/ true);
}
return cache[key] = result;
}

function isMatchingReferenceDiscriminant(expr: Expression) {
Expand Down
63 changes: 63 additions & 0 deletions tests/baselines/reference/nestedLoopTypeGuards.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,63 @@
//// [nestedLoopTypeGuards.ts]
// Repros from #10378

function f1() {
var a: boolean | number | string;
if (typeof a !== 'boolean') {
// a is narrowed to "number | string"
for (var i = 0; i < 1; i++) {
for (var j = 0; j < 1; j++) {}
if (typeof a === 'string') {
// a is narrowed to "string'
for (var j = 0; j < 1; j++) {
a.length; // Should not error here
}
}
}
}
}

function f2() {
var a: string | number;
if (typeof a === 'string') {
while (1) {
while (1) {}
if (typeof a === 'string') {
while (1) {
a.length; // Should not error here
}
}
}
}
}

//// [nestedLoopTypeGuards.js]
// Repros from #10378
function f1() {
var a;
if (typeof a !== 'boolean') {
// a is narrowed to "number | string"
for (var i = 0; i < 1; i++) {
for (var j = 0; j < 1; j++) { }
if (typeof a === 'string') {
// a is narrowed to "string'
for (var j = 0; j < 1; j++) {
a.length; // Should not error here
}
}
}
}
}
function f2() {
var a;
if (typeof a === 'string') {
while (1) {
while (1) { }
if (typeof a === 'string') {
while (1) {
a.length; // Should not error here
}
}
}
}
}
66 changes: 66 additions & 0 deletions tests/baselines/reference/nestedLoopTypeGuards.symbols
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,66 @@
=== tests/cases/compiler/nestedLoopTypeGuards.ts ===
// Repros from #10378

function f1() {
>f1 : Symbol(f1, Decl(nestedLoopTypeGuards.ts, 0, 0))

var a: boolean | number | string;
>a : Symbol(a, Decl(nestedLoopTypeGuards.ts, 3, 7))

if (typeof a !== 'boolean') {
>a : Symbol(a, Decl(nestedLoopTypeGuards.ts, 3, 7))

// a is narrowed to "number | string"
for (var i = 0; i < 1; i++) {
>i : Symbol(i, Decl(nestedLoopTypeGuards.ts, 6, 16))
>i : Symbol(i, Decl(nestedLoopTypeGuards.ts, 6, 16))
>i : Symbol(i, Decl(nestedLoopTypeGuards.ts, 6, 16))

for (var j = 0; j < 1; j++) {}
>j : Symbol(j, Decl(nestedLoopTypeGuards.ts, 7, 20), Decl(nestedLoopTypeGuards.ts, 10, 24))
>j : Symbol(j, Decl(nestedLoopTypeGuards.ts, 7, 20), Decl(nestedLoopTypeGuards.ts, 10, 24))
>j : Symbol(j, Decl(nestedLoopTypeGuards.ts, 7, 20), Decl(nestedLoopTypeGuards.ts, 10, 24))

if (typeof a === 'string') {
>a : Symbol(a, Decl(nestedLoopTypeGuards.ts, 3, 7))

// a is narrowed to "string'
for (var j = 0; j < 1; j++) {
>j : Symbol(j, Decl(nestedLoopTypeGuards.ts, 7, 20), Decl(nestedLoopTypeGuards.ts, 10, 24))
>j : Symbol(j, Decl(nestedLoopTypeGuards.ts, 7, 20), Decl(nestedLoopTypeGuards.ts, 10, 24))
>j : Symbol(j, Decl(nestedLoopTypeGuards.ts, 7, 20), Decl(nestedLoopTypeGuards.ts, 10, 24))

a.length; // Should not error here
>a.length : Symbol(String.length, Decl(lib.d.ts, --, --))
>a : Symbol(a, Decl(nestedLoopTypeGuards.ts, 3, 7))
>length : Symbol(String.length, Decl(lib.d.ts, --, --))
}
}
}
}
}

function f2() {
>f2 : Symbol(f2, Decl(nestedLoopTypeGuards.ts, 16, 1))

var a: string | number;
>a : Symbol(a, Decl(nestedLoopTypeGuards.ts, 19, 7))

if (typeof a === 'string') {
>a : Symbol(a, Decl(nestedLoopTypeGuards.ts, 19, 7))

while (1) {
while (1) {}
if (typeof a === 'string') {
>a : Symbol(a, Decl(nestedLoopTypeGuards.ts, 19, 7))

while (1) {
a.length; // Should not error here
>a.length : Symbol(String.length, Decl(lib.d.ts, --, --))
>a : Symbol(a, Decl(nestedLoopTypeGuards.ts, 19, 7))
>length : Symbol(String.length, Decl(lib.d.ts, --, --))
}
}
}
}
}
96 changes: 96 additions & 0 deletions tests/baselines/reference/nestedLoopTypeGuards.types
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,96 @@
=== tests/cases/compiler/nestedLoopTypeGuards.ts ===
// Repros from #10378

function f1() {
>f1 : () => void

var a: boolean | number | string;
>a : string | number | boolean

if (typeof a !== 'boolean') {
>typeof a !== 'boolean' : boolean
>typeof a : string
>a : string | number | boolean
>'boolean' : "boolean"

// a is narrowed to "number | string"
for (var i = 0; i < 1; i++) {
>i : number
>0 : number
>i < 1 : boolean
>i : number
>1 : number
>i++ : number
>i : number

for (var j = 0; j < 1; j++) {}
>j : number
>0 : number
>j < 1 : boolean
>j : number
>1 : number
>j++ : number
>j : number

if (typeof a === 'string') {
>typeof a === 'string' : boolean
>typeof a : string
>a : string | number
>'string' : "string"

// a is narrowed to "string'
for (var j = 0; j < 1; j++) {
>j : number
>0 : number
>j < 1 : boolean
>j : number
>1 : number
>j++ : number
>j : number

a.length; // Should not error here
>a.length : number
>a : string
>length : number
}
}
}
}
}

function f2() {
>f2 : () => void

var a: string | number;
>a : string | number

if (typeof a === 'string') {
>typeof a === 'string' : boolean
>typeof a : string
>a : string | number
>'string' : "string"

while (1) {
>1 : number

while (1) {}
>1 : number

if (typeof a === 'string') {
>typeof a === 'string' : boolean
>typeof a : string
>a : string
>'string' : "string"

while (1) {
>1 : number

a.length; // Should not error here
>a.length : number
>a : string
>length : number
}
}
}
}
}
31 changes: 31 additions & 0 deletions tests/cases/compiler/nestedLoopTypeGuards.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,31 @@
// Repros from #10378

function f1() {
var a: boolean | number | string;
if (typeof a !== 'boolean') {
// a is narrowed to "number | string"
for (var i = 0; i < 1; i++) {
for (var j = 0; j < 1; j++) {}
if (typeof a === 'string') {
// a is narrowed to "string'
for (var j = 0; j < 1; j++) {
a.length; // Should not error here
}
}
}
}
}

function f2() {
var a: string | number;
if (typeof a === 'string') {
while (1) {
while (1) {}
if (typeof a === 'string') {
while (1) {
a.length; // Should not error here
}
}
}
}
}