Add logical assignment operator #37727

Kingwl · 2020-04-01T03:09:33Z

DanielRosenwasser · 2020-04-01T09:13:10Z

~~The GitHub app is terrible so I can't review properly, but test 5 uses a function type returning void | undefined. That's probably a mistake.~~

Resolved

DanielRosenwasser · 2020-04-01T19:36:52Z

tests/baselines/reference/logicalAssignment5(target=es2020).errors.txt

+    }
+
+    function foo2 (f?: (a: number) => void) {
+        f ||= (a => a)


Great test!

DanielRosenwasser · 2020-04-01T19:39:42Z

tests/baselines/reference/logicalAssignment4(target=es2015).errors.txt

+        if (thing &&= thing.original) {
+            console.log(thing.name);
+                        ~~~~~
+!!! error TS2532: Object is possibly 'undefined'.


Glad the test caught this - that was part of my intent when I wrote it. As you probably know, this needs to be fixed because thing.original should be defined. Let @ahejlsberg or @rbuckton know if you need help with that.

I spent all afternoon And evening in this one😂

Yeah, the code can be hard to get through, and I've honestly never wired up the CFG. Also, binary expressions recently changed to use a "trampolining" approach to avoid stack overflows on deep traversals. You can ask @weswigham about that.

If you want to play around to see if you can get it working, I'll provide a few tips and @weswigham and @ahejlsberg can weigh in case I'm totally off.

First take a look at some of the logic at

TypeScript/src/compiler/binder.ts

Line 1418 in b58a29b

const preRightLabel = createBranchLabel();

and

TypeScript/src/compiler/binder.ts

Line 1513 in b58a29b

if (operator === SyntaxKind.AmpersandAmpersandToken || operator === SyntaxKind.BarBarToken || operator === SyntaxKind.QuestionQuestionToken) {

The binder needs to create branch labels for these new compound assignment operators (similar to in bindLogicalExpression) while creating at least one flow node that's considered an assignment after the expression (as in bindAssignmentTargetFlow). At a glance, I think that a lot of the logic can be reused and the changes can be added around here

Eventually in getTypeAtFlowNode in the type-checker, you need to try to find a way to combine the logic when flags & FlowFlags.Assignment and flags & FlowFlags.Label both apply. To start, I'd just get something working, then worry about how to share the code.

Feel free to ask some questions if you need help. If you'd prefer, I'm also sure we could send a PR if you'd like, but it's up to you.

DanielRosenwasser · 2020-04-01T19:43:29Z

src/compiler/utilities.ts

@@ -4355,6 +4365,12 @@ namespace ts {
            || token === SyntaxKind.ExclamationToken;
    }

+    export function isLogicalAssignmentOperator(token: SyntaxKind): boolean {


Consider isShortCircuitingAssignmentOperator or isLogicalOrCoalescingAssignmentOperator

DanielRosenwasser · 2020-04-01T19:47:37Z

src/compiler/utilities.ts

@@ -3334,6 +3340,10 @@ namespace ts {
                return 14;
            case SyntaxKind.AsteriskAsteriskToken:
                return 15;
+            case SyntaxKind.BarBarEqualsToken:


This section doesn't seem to cover any of the assignment or compound assignment operators. I'd get clarity from whoever originally wrote this function whether this should be here, because I think these 3 cases don't belong here.

Yeah, it seems to be caught by getOperatorPrecedence above.

src/compiler/transformers/utilities.ts

src/compiler/checker.ts

Kingwl · 2020-04-02T08:05:12Z

It seems works, but i don't know why.🤷🏻‍♂️

DanielRosenwasser · 2020-04-02T08:06:42Z

@typescript-bot pack this

typescript-bot · 2020-04-02T08:06:47Z

Heya @DanielRosenwasser, I've started to run the tarball bundle task on this PR at 1c92781. You can monitor the build here.

src/compiler/binder.ts

Kingwl · 2020-04-02T08:23:15Z

Current CFG is

"
Call (results.push(100)) ─ ArrayMutation (results.push(100)) ─ Branch ┬ True (results) ─────────────────────────────────────────────────┬ Start  
                                                                      ├ True (results ||= []) ─┬ Assignment (results) ─ False (results) ╯   
                                                                      ╰ False (results ||= []) ╯                                            
"

the same as downlevel result

"
Call (results.push(100)) ─ ArrayMutation (results.push(100)) ─ Branch ┬ True (results) ─────────────────────────────────────────────────┬ Start  
                                                                      ├ True ((results = [])) ─┬ Assignment (results) ─ False (results) ╯   
                                                                      ╰ False ((results = [])) ╯                                            
"

Kingwl · 2020-04-02T08:54:58Z

@typescript-bot pack this.

typescript-bot · 2020-04-02T08:55:04Z

Heya @Kingwl, I've started to run the tarball bundle task on this PR at a6e0086. You can monitor the build here.

typescript-bot · 2020-04-02T09:10:52Z

Hey @Kingwl, I've packed this into an installable tgz. You can install it for testing by referencing it in your package.json like so:

{
    "devDependencies": {
        "typescript": "https://typescript.visualstudio.com/cf7ac146-d525-443c-b23c-0d58337efebc/_apis/build/builds/70160/artifacts?artifactName=tgz&fileId=686926927B2177B6DF8E5E65AF663CA3F21F8E4A6BB13BA2F0D55123942814F102&fileName=/typescript-3.9.0-insiders.20200402.tgz"
    }
}

and then running npm install.

Kingwl · 2020-04-04T15:00:39Z

@typescript-bot pack this.

typescript-bot · 2020-04-04T15:01:16Z

Heya @Kingwl, I've started to run the tarball bundle task on this PR at 8a9e234. You can monitor the build here.

typescript-bot · 2020-04-04T15:15:34Z

Hey @Kingwl, I've packed this into an installable tgz. You can install it for testing by referencing it in your package.json like so:

{
    "devDependencies": {
        "typescript": "https://typescript.visualstudio.com/cf7ac146-d525-443c-b23c-0d58337efebc/_apis/build/builds/70428/artifacts?artifactName=tgz&fileId=0F5F796F0B11C552E9CE937F66A4E8AFB940559C729165A9D4B3FAFEB190B56302&fileName=/typescript-3.9.0-insiders.20200404.tgz"
    }
}

and then running npm install.

Kingwl · 2020-04-07T02:09:45Z

Does the playground not supported pull request build now?🤷🏻‍♂️

DanielRosenwasser · 2020-04-07T18:31:10Z

Does the playground not supported pull request build now?

@weswigham or @orta might know

orta · 2020-04-07T21:49:40Z

Thanks for the ping, looks like I need to dig into the playground builder - been red for a week
https://github.com/orta/make-monaco-builds/actions - looks like a master build of TS gives a new error in the monaco-typescript codebase

orta · 2020-04-07T22:03:55Z

Made a PR: microsoft/monaco-typescript#59

orta · 2020-04-07T22:10:53Z

and with orta/make-monaco-builds@f17ca4a in

I can request a playground again - @typescript-bot pack this.

typescript-bot · 2020-04-07T22:10:57Z

Heya @orta, I've started to run the tarball bundle task on this PR at 8a9e234. You can monitor the build here.

typescript-bot · 2020-04-07T22:24:56Z

Hey @orta, I've packed this into an installable tgz. You can install it for testing by referencing it in your package.json like so:

{
    "devDependencies": {
        "typescript": "https://typescript.visualstudio.com/cf7ac146-d525-443c-b23c-0d58337efebc/_apis/build/builds/70644/artifacts?artifactName=tgz&fileId=C1043CC14B2BF52EEC192CF7805DCDB9972F4A315657B65C7F9096429256B57A02&fileName=/typescript-3.9.0-insiders.20200407.tgz"
    }
}

and then running npm install.

There is also a playground for this build.

Kingwl · 2020-05-16T00:57:55Z

Only one pipeline failed with ECONNRESET.

DanielRosenwasser · 2020-05-20T00:14:12Z

Looks like this needs to be rebased onto the latest master.

src/compiler/parser.ts

DanielRosenwasser · 2020-05-20T21:23:09Z

One more review?

tests/cases/conformance/esnext/logicalAssignment/logicalAssignment2.ts

tests/baselines/reference/logicalAssignment5(target=es2015).errors.txt

src/compiler/transformers/esnext.ts

DanielRosenwasser · 2020-05-27T23:03:23Z

One more peek @rbuckton?

Kingwl · 2020-06-03T13:54:04Z

up👆

aminpaks · 2020-06-16T03:03:40Z

@Kingwl I mentioned a case in here. Would you confirm that this is not a bug?

Xample · 2020-07-24T10:40:36Z

Glad to see things moved since #20378 😀

g-patel · 2020-09-03T20:21:48Z

What version of typescript will this be available in?

ExE-Boss · 2020-09-03T20:44:35Z

@g-patel This shipped in TypeScript 4.0.

DanielRosenwasser reviewed Apr 1, 2020

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Kingwl force-pushed the logical_assignment branch from 2f6dfd7 to 1c92781 Compare April 2, 2020 08:04

DanielRosenwasser reviewed Apr 2, 2020

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Kingwl force-pushed the logical_assignment branch from 17b858c to 1ed6a3e Compare April 4, 2020 14:11

Kingwl marked this pull request as ready for review April 4, 2020 14:32

Kingwl force-pushed the logical_assignment branch from f17eb88 to 39ae072 Compare May 16, 2020 00:11

Kingwl added 2 commits May 16, 2020 08:13

fix rebase conflict

acc167d

accept new baseline

6f393e9

DanielRosenwasser requested changes May 20, 2020

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Merge branch 'master' into logical_assignment

b59e4c5

Kingwl force-pushed the logical_assignment branch from ad70d78 to b59e4c5 Compare May 20, 2020 02:18

rbuckton requested changes May 20, 2020

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Kingwl added 3 commits May 21, 2020 10:19

Fix type and simplify code

b73411c

fix names

2997860

Accept baseline

fed922a

DanielRosenwasser approved these changes May 27, 2020

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rbuckton approved these changes Jun 9, 2020

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PR Backlog automation moved this from Waiting on author to Needs merge Jun 9, 2020

DanielRosenwasser merged commit e832e04 into microsoft:master Jun 9, 2020

PR Backlog automation moved this from Needs merge to Done Jun 9, 2020

Kingwl deleted the logical_assignment branch June 10, 2020 00:35

evanw mentioned this pull request Jun 20, 2020

Side effect bugs with logical assignment #39172

Closed

jcalz mentioned this pull request Aug 7, 2020

Logical Unary Assignment Operators &&= and ||= #31011

Closed

schickling mentioned this pull request Jan 27, 2021

Support logical assignment operator evanw/esbuild#715

Closed

jonculver mentioned this pull request Jul 13, 2021

Extension fails to load on remotes microsoft/vscode-test-adapter-converter#5

Closed

github-actions bot mentioned this pull request Oct 4, 2022

[Korean] Fix weird expressions like '_제네릭_' microsoft/TypeScript-Website-Localizations#171

Merged

Add logical assignment operator #37727

Add logical assignment operator #37727

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