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Generic function constraints degrade in conditionas but work in higher order functions

5

### 🔎 Search Terms * generic * constraint * higher order generic * higher order generic function * constraint generic ### 🕗 Version & Regression Information - This is the...

peterhudec

Bring back return type narrowing + fixes

9

Fixes #33014. Fixes #33912. This PR brings back conditional and indexed access return type narrowing from #56941, but with a few updates. The main motivation behind those updates is described...

gabritto

### 🔎 Search Terms iteration yield iterator symbol generic call inference ### 🕗 Version & Regression Information - This is the behavior in every version I tried ### ⏯ Playground...

Andarist

Class satisfies type

5

### 🔍 Search Terms class satisfies ### ✅ Viability Checklist - [x] This wouldn't be a breaking change in existing TypeScript/JavaScript code - [x] This wouldn't change the runtime behavior...

sdegutis

### 🔎 Search Terms instantiable contextual signature return types ### 🕗 Version & Regression Information - This is the behavior in every version I tried ### ⏯ Playground Link https://www.typescriptlang.org/play/?ts=5.8.0-dev.20250216#code/C4TwDgpgBAwg9gO2BAHsAysAhsgzlAXgCgooAfKAbxNNt22AFdcAuKAIgBs4sATASwQBzdgG4atKLxxY2CRp07jJAXxoVqk0vRzM27XIwDGRiLlxiJtadjb0AToKHLaK8UV4QjnLPegAzRgQjYH5EKCM-HAhMOD8AHgAVeCRUYAA+AAoaI0RkNDZkvLSAGhzEf34hNk1aRDYAJS843niHJxKoTJCUQpT84ABKQnSoItS0dJcVMsG2ADc4fl53XIR6KHo46AIIqORYv2zSWu0GPQ5uPid2MskbWSh5RTuoFSgsfH60zGjcV9OUHqVCspH8EGARgAFmxMsMCKNMoDJDomKwOIYTGYLK8tFIZPooRBFHBbqC3oNcW9XjMiINxEA...

Andarist

### 🔎 Search Terms "intellisense template literal", "intellisense property union" ### 🕗 Version & Regression Information - This is the behavior in every version I tried (v4.9.5, v5.8.2) ### ⏯...

gordonmleigh

JSX types should automatically pick setter types instead of getter types.

1

### 🔍 Search Terms "typescript github jsx setter type" Related: - https://github.com/microsoft/TypeScript/issues/60162 (however that issue is for mapped types in general, while this one is for fixing how TypeScript's internal...

trusktr

### 🔍 Search Terms readonly target library ### ✅ Viability Checklist - [x] This wouldn't be a breaking change in existing TypeScript/JavaScript code - [x] This wouldn't change the runtime...

Renegade334

[WIP] Disallow merging of `enum` declarations

10

This is an experiment to access the impact of disallowing the merging of `enum` declarations.

rbuckton

Be strict about package.json JSON syntax

6

Corsa is strict about this, so tests break in weird ways due to these random trailing commas/comments. Be strict here, then fix the tests.

jakebailey