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Add explicit tests for unconstrained type param not being assignable to {} and Record<string, any> #48421

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Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
tests/cases/compiler/genericUnboundedTypeParamAssignability.ts(2,5): error TS2339: Property 'toString' does not exist on type 'T'.
tests/cases/compiler/genericUnboundedTypeParamAssignability.ts(15,6): error TS2345: Argument of type 'T' is not assignable to parameter of type '{}'.
tests/cases/compiler/genericUnboundedTypeParamAssignability.ts(16,6): error TS2345: Argument of type 'T' is not assignable to parameter of type 'Record<string, any>'.
tests/cases/compiler/genericUnboundedTypeParamAssignability.ts(17,5): error TS2339: Property 'toString' does not exist on type 'T'.


==== tests/cases/compiler/genericUnboundedTypeParamAssignability.ts (4 errors) ====
function f1<T>(o: T) {
o.toString(); // error
~~~~~~~~
!!! error TS2339: Property 'toString' does not exist on type 'T'.
}

function f2<T extends {}>(o: T) {
o.toString(); // no error
}

function f3<T extends Record<string, any>>(o: T) {
o.toString(); // no error
}

function user<T>(t: T) {
f1(t);
f2(t); // error in strict, unbounded T doesn't satisfy the constraint
~
!!! error TS2345: Argument of type 'T' is not assignable to parameter of type '{}'.
!!! related TS2208 tests/cases/compiler/genericUnboundedTypeParamAssignability.ts:13:15: This type parameter probably needs an `extends object` constraint.
f3(t); // error in strict, unbounded T doesn't satisfy the constraint
~
!!! error TS2345: Argument of type 'T' is not assignable to parameter of type 'Record<string, any>'.
!!! related TS2208 tests/cases/compiler/genericUnboundedTypeParamAssignability.ts:13:15: This type parameter probably needs an `extends object` constraint.
t.toString(); // error, for the same reason as f1()
~~~~~~~~
!!! error TS2339: Property 'toString' does not exist on type 'T'.
}

Original file line number Diff line number Diff line change
@@ -0,0 +1,38 @@
//// [genericUnboundedTypeParamAssignability.ts]
function f1<T>(o: T) {
o.toString(); // error
}

function f2<T extends {}>(o: T) {
o.toString(); // no error
}

function f3<T extends Record<string, any>>(o: T) {
o.toString(); // no error
}

function user<T>(t: T) {
f1(t);
f2(t); // error in strict, unbounded T doesn't satisfy the constraint
f3(t); // error in strict, unbounded T doesn't satisfy the constraint
t.toString(); // error, for the same reason as f1()
}


//// [genericUnboundedTypeParamAssignability.js]
"use strict";
function f1(o) {
o.toString(); // error
}
function f2(o) {
o.toString(); // no error
}
function f3(o) {
o.toString(); // no error
}
function user(t) {
f1(t);
f2(t); // error in strict, unbounded T doesn't satisfy the constraint
f3(t); // error in strict, unbounded T doesn't satisfy the constraint
t.toString(); // error, for the same reason as f1()
}
Original file line number Diff line number Diff line change
@@ -0,0 +1,58 @@
=== tests/cases/compiler/genericUnboundedTypeParamAssignability.ts ===
function f1<T>(o: T) {
>f1 : Symbol(f1, Decl(genericUnboundedTypeParamAssignability.ts, 0, 0))
>T : Symbol(T, Decl(genericUnboundedTypeParamAssignability.ts, 0, 12))
>o : Symbol(o, Decl(genericUnboundedTypeParamAssignability.ts, 0, 15))
>T : Symbol(T, Decl(genericUnboundedTypeParamAssignability.ts, 0, 12))

o.toString(); // error
>o : Symbol(o, Decl(genericUnboundedTypeParamAssignability.ts, 0, 15))
}

function f2<T extends {}>(o: T) {
>f2 : Symbol(f2, Decl(genericUnboundedTypeParamAssignability.ts, 2, 1))
>T : Symbol(T, Decl(genericUnboundedTypeParamAssignability.ts, 4, 12))
>o : Symbol(o, Decl(genericUnboundedTypeParamAssignability.ts, 4, 26))
>T : Symbol(T, Decl(genericUnboundedTypeParamAssignability.ts, 4, 12))

o.toString(); // no error
>o.toString : Symbol(Object.toString, Decl(lib.es5.d.ts, --, --))
>o : Symbol(o, Decl(genericUnboundedTypeParamAssignability.ts, 4, 26))
>toString : Symbol(Object.toString, Decl(lib.es5.d.ts, --, --))
}

function f3<T extends Record<string, any>>(o: T) {
>f3 : Symbol(f3, Decl(genericUnboundedTypeParamAssignability.ts, 6, 1))
>T : Symbol(T, Decl(genericUnboundedTypeParamAssignability.ts, 8, 12))
>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
>o : Symbol(o, Decl(genericUnboundedTypeParamAssignability.ts, 8, 43))
>T : Symbol(T, Decl(genericUnboundedTypeParamAssignability.ts, 8, 12))

o.toString(); // no error
>o.toString : Symbol(Object.toString, Decl(lib.es5.d.ts, --, --))
>o : Symbol(o, Decl(genericUnboundedTypeParamAssignability.ts, 8, 43))
>toString : Symbol(Object.toString, Decl(lib.es5.d.ts, --, --))
}

function user<T>(t: T) {
>user : Symbol(user, Decl(genericUnboundedTypeParamAssignability.ts, 10, 1))
>T : Symbol(T, Decl(genericUnboundedTypeParamAssignability.ts, 12, 14))
>t : Symbol(t, Decl(genericUnboundedTypeParamAssignability.ts, 12, 17))
>T : Symbol(T, Decl(genericUnboundedTypeParamAssignability.ts, 12, 14))

f1(t);
>f1 : Symbol(f1, Decl(genericUnboundedTypeParamAssignability.ts, 0, 0))
>t : Symbol(t, Decl(genericUnboundedTypeParamAssignability.ts, 12, 17))

f2(t); // error in strict, unbounded T doesn't satisfy the constraint
>f2 : Symbol(f2, Decl(genericUnboundedTypeParamAssignability.ts, 2, 1))
>t : Symbol(t, Decl(genericUnboundedTypeParamAssignability.ts, 12, 17))

f3(t); // error in strict, unbounded T doesn't satisfy the constraint
>f3 : Symbol(f3, Decl(genericUnboundedTypeParamAssignability.ts, 6, 1))
>t : Symbol(t, Decl(genericUnboundedTypeParamAssignability.ts, 12, 17))

t.toString(); // error, for the same reason as f1()
>t : Symbol(t, Decl(genericUnboundedTypeParamAssignability.ts, 12, 17))
}

Original file line number Diff line number Diff line change
@@ -0,0 +1,60 @@
=== tests/cases/compiler/genericUnboundedTypeParamAssignability.ts ===
function f1<T>(o: T) {
>f1 : <T>(o: T) => void
>o : T

o.toString(); // error
>o.toString() : any
>o.toString : any
>o : T
>toString : any
}

function f2<T extends {}>(o: T) {
>f2 : <T extends {}>(o: T) => void
>o : T

o.toString(); // no error
>o.toString() : string
>o.toString : () => string
>o : T
>toString : () => string
}

function f3<T extends Record<string, any>>(o: T) {
>f3 : <T extends Record<string, any>>(o: T) => void
>o : T

o.toString(); // no error
>o.toString() : string
>o.toString : () => string
>o : T
>toString : () => string
}

function user<T>(t: T) {
>user : <T>(t: T) => void
>t : T

f1(t);
>f1(t) : void
>f1 : <T>(o: T) => void
>t : T

f2(t); // error in strict, unbounded T doesn't satisfy the constraint
>f2(t) : void
>f2 : <T extends {}>(o: T) => void
>t : T

f3(t); // error in strict, unbounded T doesn't satisfy the constraint
>f3(t) : void
>f3 : <T extends Record<string, any>>(o: T) => void
>t : T

t.toString(); // error, for the same reason as f1()
>t.toString() : any
>t.toString : any
>t : T
>toString : any
}

20 changes: 20 additions & 0 deletions tests/cases/compiler/genericUnboundedTypeParamAssignability.ts
Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
// @strict: true

function f1<T>(o: T) {
o.toString(); // error
}

function f2<T extends {}>(o: T) {
o.toString(); // no error
}

function f3<T extends Record<string, any>>(o: T) {
o.toString(); // no error
}

function user<T>(t: T) {
f1(t);
f2(t); // error in strict, unbounded T doesn't satisfy the constraint
f3(t); // error in strict, unbounded T doesn't satisfy the constraint
t.toString(); // error, for the same reason as f1()
}