# AN-2026-0746: TypeScript 6.0+ defaults rootDir to the tsconfig.json directory: TS5011 and output nested as dist/src/index.js unless rootDir is set

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- id: AN-2026-0746 (version 1; cite https://breakwire.org/claim/AN-2026-0746/v/1)
- kind: breaking · status: active · review: editor
- source: <https://devblogs.microsoft.com/typescript/announcing-typescript-6-0/#:~:text=the%20default%20rootDir%20will%20always%20be>
- more sources: <https://raw.githubusercontent.com/microsoft/TypeScript/v6.0.3/src/compiler/diagnosticMessages.json> <https://devblogs.microsoft.com/typescript/announcing-typescript-7-0/>
- event date: 2026-03-23
- services: typescript
- affected: npm:typescript >=6.0.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The TypeScript 6.0 announcement (opened 2026-11-04) says the default rootDir is now always the directory containing tsconfig.json (previously inferred from the common directory of the input files); it is inferred only when tsc runs without a tsconfig.json.  [✓0 ✗0]
1. It says projects with sources below the tsconfig directory need "rootDir": "./src", and that you often know this is the issue if files are written to ./dist/src/index.js instead of ./dist/index.js; the TypeScript 7.0 announcement lists the same default.  [✓0 ✗0]
2. diagnosticMessages.json at v6.0.3 defines 5011 (The common source directory of '{0}' is '{1}'. The 'rootDir' setting must be explicitly set to this or another path to adjust your output's file layout.); the code is not in v5.9.3. Reproduced 2026-11-04 with typescript 6.0.3: tsconfig with outDir dist, include src, no rootDir -> TS5011 and output under dist/src.  [✓0 ✗0]

## Fix
```text
Set compilerOptions.rootDir explicitly (e.g. "rootDir": "./src" with "include": ["./src"], or "../src" if the sources live outside the tsconfig directory).
```

## Error signatures
- substring: `The 'rootDir' setting must be explicitly set to this or another path to adjust your output's file layout` (TS5011, diagnosticMessages.json v6.0.3)

## Outcome reports (0)
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## History
- v1 2026-11-04 by wire-editor: filed from primary sources opened 2026-11-04 (TS 6.0/7.0 announcements, diagnosticMessages v6.0.3, typescript-go v7.0.2; reproduced with typescript 6.0.3/7.0.2)