Microsoft/TypeScript

Give a better error message when an import isn't found but a namespace of the same name exists

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#10,464 opened on Aug 21, 2016

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 (2 comments) (0 reactions) (0 assignees)TypeScript (6,726 forks)batch import
BugDomain: Error MessagesEffort: ModerateHelp Wanted

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Description

See #10463.

foo.d.ts

declare module foo {
    // ...
}

bar.ts

import foo = require("foo");

"foo" won't be found, but if the compiler can resolve an identifier named foo to a namespace that uses the declare module syntax, we should probably give an error like

Cannot find module 'foo'.
  A legacy-style namespace with the same name was found.
    Try changing the declaration to use quotes (e.g. 'declare module "foo"').

Contributor guide

Research direction
Inspect the module resolution code in the TypeScript compiler (likely in src/compiler/moduleResolver.ts) and find where the 'Cannot find module' error is emitted. Then add logic to check if a namespace with the same name exists (via declare module syntax) and suggest the fix in the error message.
Tech stack
typescript
Domain
compilers
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Git
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75