Method isPartiallyInferableType

internal/checker/inference.go:1026–1030

We consider a type to be partially inferable if it isn't marked non-inferable or if it is an object literal type with at least one property of an inferable type. For example, an object literal { a: 123, b: x => true } is marked non-inferable because it contains a context sensitive arrow function, bu

(t *Type)

// literal { a: 123, b: x => true } is marked non-inferable because it contains a context sensitive
// arrow function, but is considered partially inferable because property 'a' has an inferable type.
func (c *Checker) isPartiallyInferableType(t *Type) bool {
	return t.objectFlags&ObjectFlagsNonInferrableType == 0 || isObjectLiteralType(t) && core.Some(c.getPropertiesOfType(t), func(prop *ast.Symbol) bool {
		return c.isPartiallyInferableType(c.getTypeOfSymbol(prop))
	}) || isTupleType(t) && core.Some(c.getElementTypes(t), c.isPartiallyInferableType)
}

func (c *Checker) inferReverseMappedType(source *Type, target *Type, constraint *Type) *Type {
	key := ReverseMappedTypeKey{sourceId: source.id, targetId: target.id, constraintId: constraint.id}