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tests/cases/compiler/genericSpecializations2.ts(8,5): error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type 'IFoo<number>'.
Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
Types of parameters 'x' and 'x' are incompatible.
Type 'T' is not assignable to type 'string'.
tests/cases/compiler/genericSpecializations2.ts(8,9): error TS2368: Type parameter name cannot be 'string'.
tests/cases/compiler/genericSpecializations2.ts(12,5): error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type 'IFoo<string>'.
Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
Types of parameters 'x' and 'x' are incompatible.
Type 'T' is not assignable to type 'string'.
tests/cases/compiler/genericSpecializations2.ts(12,9): error TS2368: Type parameter name cannot be 'string'.
==== tests/cases/compiler/genericSpecializations2.ts (4 errors) ====
class IFoo<T> {
foo<T>(x: T): T { // no error on implementors because IFoo's T is different from foo's T
return null;
}
}
class IntFooBad implements IFoo<number> {
foo<string>(x: string): string { return null; }
~~~
!!! error TS2416: Property 'foo' in type 'IntFooBad' is not assignable to the same property in base type 'IFoo<number>'.
!!! error TS2416: Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
!!! error TS2416: Types of parameters 'x' and 'x' are incompatible.
!!! error TS2416: Type 'T' is not assignable to type 'string'.
!!! related TS2208 tests/cases/compiler/genericSpecializations2.ts:2:9: This type parameter might need an `extends string` constraint.
~~~~~~
!!! error TS2368: Type parameter name cannot be 'string'.
}
class StringFoo2 implements IFoo<string> {
foo<string>(x: string): string { return null; }
~~~
!!! error TS2416: Property 'foo' in type 'StringFoo2' is not assignable to the same property in base type 'IFoo<string>'.
!!! error TS2416: Type '<string>(x: string) => string' is not assignable to type '<T>(x: T) => T'.
!!! error TS2416: Types of parameters 'x' and 'x' are incompatible.
!!! error TS2416: Type 'T' is not assignable to type 'string'.
!!! related TS2208 tests/cases/compiler/genericSpecializations2.ts:2:9: This type parameter might need an `extends string` constraint.
~~~~~~
!!! error TS2368: Type parameter name cannot be 'string'.
}
class StringFoo3 implements IFoo<string> {
foo<T>(x: T): T { return null; }
}
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