fix(eslint-plugin): [no-duplicate-imports] remove unnecessary type checking for node.source

[sosukesuzuki]

PR Checklist

• Addresses an existing issue: fixes #000
• That issue was marked as accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Since v5.x, source of ExportNamedDeclaration, ExportAllDeclaration and ImportDeclaration is always StringLiteral.

[typescript-eslint]

Thanks for the PR, @sosukesuzuki!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[netlify]

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[nx-cloud]

Nx Cloud Report

CI ran the following commands for commit 4d303b8. Click to see the status, the terminal output, and the build insights.

📂 See all runs for this branch

Status	Command
	Node 16.x - nx test @typescript-eslint/eslint-plugin-tslint
	Node 16.x - nx test @typescript-eslint/eslint-plugin
	Node 12.x - nx test @typescript-eslint/eslint-plugin-internal
	Node 12.x - nx test @typescript-eslint/eslint-plugin-tslint
	Node 12.x - nx test @typescript-eslint/eslint-plugin
	Node 14.x - nx test @typescript-eslint/eslint-plugin-tslint
	Node 14.x - nx test @typescript-eslint/eslint-plugin
	Node 12.x - nx test @typescript-eslint/eslint-plugin-tslint
	Node 12.x - nx test @typescript-eslint/eslint-plugin
	Node 12.x - nx run-many --target=typecheck --all --parallel
	Node 16.x - nx test @typescript-eslint/parser
	Node 16.x - nx test @typescript-eslint/experimental-utils
	Node 12.x - nx test @typescript-eslint/parser
	Node 16.x - nx test @typescript-eslint/scope-manager
	Node 12.x - nx test @typescript-eslint/experimental-utils
	Node 16.x - nx test @typescript-eslint/visitor-keys
	Node 14.x - nx test @typescript-eslint/parser
	Node 12.x - nx test @typescript-eslint/scope-manager
	Node 14.x - nx test @typescript-eslint/experimental-utils
	Node 12.x - nx run-many --target=build --all --parallel --exclude website --exclude website

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[codecov]

Codecov Report

Merging #4196 (4d303b8) into main (2e2ff5d) will increase coverage by 0.60%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##             main    #4196      +/-   ##
==========================================
+ Coverage   92.76%   93.36%   +0.60%     
==========================================
  Files         332      152     -180     
  Lines       11524     8051    -3473     
  Branches     3285     2585     -700     
==========================================
- Hits        10690     7517    -3173     
+ Misses        361      179     -182     
+ Partials      473      355     -118     

Flag	Coverage Δ
unittest	93.36% <50.00%> (+0.60%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...es/eslint-plugin/src/rules/no-duplicate-imports.ts	95.34% <50.00%> (-0.21%)	⬇️
packages/scope-manager/src/scope/FunctionScope.ts
packages/scope-manager/src/analyze.ts
packages/typescript-estree/src/ast-converter.ts
...s/scope-manager/src/lib/es2015.symbol.wellknown.ts
packages/scope-manager/src/lib/es7.ts
packages/scope-manager/src/scope/TypeScope.ts
...s/experimental-utils/src/eslint-utils/deepMerge.ts
...ges/experimental-utils/src/ts-eslint/RuleTester.ts
packages/scope-manager/src/lib/es2017.intl.ts
... and 171 more

[bradzacher]

thanks for cleaning this up!!