Deprecate assert in import()

[Jake Bailey (jakebailey)]

This was missed in #63077.

Perhaps slightly more dubious, given this isn't syntax per se, but interpreted at runtime?

[Copilot]

Pull request overview

This PR deprecates the use of assert in TypeScript import type expressions, requiring developers to use the newer with keyword instead. This aligns with the broader JavaScript/TypeScript evolution toward import attributes.

Changes:

• Updated test cases to use with instead of assert in import type expressions
• Added deprecation diagnostic for assert usage in import types
• Created new test files to verify deprecation warnings and ignore behavior

Reviewed changes

Copilot reviewed 47 out of 47 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/cases/conformance/node/nodeModulesImportTypeModeDeclarationEmitErrors1.ts	Updated import type syntax from assert to with
tests/cases/conformance/node/nodeModulesImportTypeModeDeclarationEmit1.ts	Updated import type syntax from assert to with
tests/cases/conformance/moduleResolution/resolutionModeImportType1.ts	Updated import type syntax from assert to with
tests/cases/compiler/parseAssertEntriesError.ts	Updated import type syntax from assert to with
tests/cases/compiler/importTypeAssertionDeprecationIgnored.ts	New test file verifying ignoreDeprecations: "6.0" suppresses the warning
tests/cases/compiler/importTypeAssertionDeprecation.ts	New test file demonstrating the deprecation warning for assert usage
tests/baselines/reference/*.types	Updated baseline files reflecting the syntax changes
tests/baselines/reference/*.symbols	Updated baseline files reflecting the syntax changes
tests/baselines/reference/*.errors.txt	Updated baseline files showing new deprecation errors for assert usage
tests/baselines/reference/*.js	Updated baseline files with emitted JavaScript output
src/compiler/checker.ts	Added deprecation check for assert keyword in import type expressions

Comments suppressed due to low confidence (1)

tests/cases/compiler/importTypeAssertionDeprecation.ts:1

• The comment on line 10 states 'Should be deprecated - uses 'assert' instead of 'with'', but the actual test file content shows line 11 also uses 'assert', while the comment on line 14 says 'Should be fine - uses 'with''. However, the baseline errors show both lines trigger deprecation errors. The test case comments are inconsistent with the actual test content - line 11 should use with if it's supposed to be 'fine'.

[Daniel Rosenwasser (DanielRosenwasser)]

We don't have a test with { assert: { type: json } }???

[Daniel Rosenwasser (DanielRosenwasser)]

These are both for qualified names - are import() type nodes also what we use in typeof import(...) and typeof import(...).someValue? If so, can we add tests for that too?

[Jake Bailey (jakebailey)]

Yeah, that's another construct I missed.

[Daniel Rosenwasser (DanielRosenwasser)]

I assume we have tests for runtime import() calls as well.