[NewErrors] 4.2.0-dev.20201122 vs 4.1.2

[typescript-bot]

The following errors were reported by 4.2.0-dev.20201122, but not by 4.1.2

ant-design

tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • components/affix/index.tsx#L240
  • components/layout/Sider.tsx#L115
  • components/upload/Upload.tsx#L200
  • site/theme/template/IconDisplay/IconPicSearcher.tsx#L112

better-scroll

test-dts/tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • file:///mnt/ts_downloads/better-scroll/node_modules/@better-scroll/shared-utils/src/lang.ts#L3
  • packages/shared-utils/src/lang.ts#L3

tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • packages/shared-utils/src/lang.ts#L3

turbolinks

tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • src/controller.ts#L21
  • src/controller.ts#L22

redux-devtools

16 of 50 projects failed to build with the old tsc

packages/map2tree/test/tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • packages/map2tree/src/index.ts#L66

packages/map2tree/tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • packages/map2tree/src/index.ts#L66

packages/redux-devtools-instrument/tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • packages/redux-devtools-instrument/src/instrument.ts#L164

packages/redux-devtools-core/test/tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • packages/redux-devtools-core/src/utils/filters.ts#L146

packages/redux-devtools-core/tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • packages/redux-devtools-core/src/utils/filters.ts#L146

brain.js

1 of 2 projects failed to build with the old tsc

tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • src/train-stream.ts#L132
  • src/train-stream.ts#L135

redoc

tsconfig.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • src/services/ClipboardService.ts#L18

tsconfig.lib.json

• error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead?
  • src/services/ClipboardService.ts#L18

[RyanCavanaugh]

Many of these are due to feature-testing the DOM but there are a couple bugs here

False positives (function is called): https://github.com/ant-design/ant-design/blob/87da555ef096489972655042ff765b893020bcb7/components/layout/Sider.tsx#L115
https://github.com/ant-design/ant-design/blob/87da555ef096489972655042ff765b893020bcb7/site/theme/template/IconDisplay/IconPicSearcher.tsx#L112
https://github.com/BrainJS/brain.js/blob/226590805bff7f841e92892edd7006edc5195f87/src/train-stream.ts#L132
https://github.com/Redocly/redoc/blob/c6b7d567d97201d2c244915a035f8c30b1152e4e/src/services/ClipboardService.ts#L18

Questionable as heck (this error probably shouldn't trigger on a casted expression): https://github.com/ant-design/ant-design/blob/87da555ef096489972655042ff765b893020bcb7/components/upload/Upload.tsx#L200
https://github.com/reduxjs/redux-devtools/blob/c980eadec70457f3713990954f43c3a3e36a6dd3/packages/map2tree/src/index.ts#L66

[sandersn]

• ant-design (1) is actually feature testing the DOM

• ant-design (2) no longer repros

• brain.js no longer repros

• redoc no longer repros (and is actually feature testing)

• ant-design (3): agree, there shouldn't be an error when a cast is involved

• redux-devtools: same