EC
TS5075
TypeScriptERRORNotableConfigHIGH confidence

'X' is assignable to the constraint of type 'X', but 'X' could be instantiate...

Production Risk

Build will fail; resolve before shipping.

What this means

A compiler configuration error (TS5075): 'X' is assignable to the constraint of type 'X', but 'X' could be instantiated with a different subtype of constraint 'X'.. This diagnostic is emitted by the TypeScript compiler when 'X' is assignable to the constraint of type 'X', but 'X' could be instantiated with a different subtype of constraint 'X'..

Why it happens
  1. 1Incorrect TypeScript syntax or type usage
  2. 2Type mismatch between declared and actual value
How to reproduce

TypeScript compiler reports TS5075 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS5075
// 'X' is assignable to the constraint of type 'X', but 'X' could be instantiated with a different subtype of constraint 'X'.

expected output

error TS5075: 'X' is assignable to the constraint of type 'X', but 'X' could be instantiated with a different subtype of constraint 'X'.

Fix

Fix the tsconfig.json option

WHEN When a compiler option is invalid or missing

Fix the tsconfig.json option
// tsconfig.json
{
  "compilerOptions": {
    // Review and correct the flagged option
  }
}
// Run: npx tsc --showConfig to see effective config

Why this works

TypeScript validates tsconfig.json options; check the official tsconfig reference for valid values.

Sources
Official documentation ↗

TypeScript Compiler Diagnostics

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