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Feed the 'this' type as a type argument to constraints during relation checking #7290

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Merged
DanielRosenwasser merged 7 commits into from
May 2, 2016
Merged

Feed the 'this' type as a type argument to constraints during relation checking #7290

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0abb4c9
Added tests.
DanielRosenwasser Feb 29, 2016
daf1596
Accepted baselines.
DanielRosenwasser Feb 29, 2016
cdd10b0
Instantiate type parameters with themselves as their 'this' type when…
DanielRosenwasser Feb 29, 2016
268b2d4
Accepted baselines.
DanielRosenwasser Feb 29, 2016
fa67cb8
Merge remote-tracking branch 'origin/master' into thisTypesInBaseProp…
DanielRosenwasser May 2, 2016
ee4baef
Applied suggested change.
DanielRosenwasser May 2, 2016
b75605e
Accepted baselines.
DanielRosenwasser May 2, 2016
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5 changes: 5 additions & 0 deletions src/compiler/checker.ts
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Expand Up @@ -5595,9 +5595,14 @@ namespace ts {

if (source.flags & TypeFlags.TypeParameter) {
let constraint = getConstraintOfTypeParameter(<TypeParameter>source);

if (!constraint || constraint.flags & TypeFlags.Any) {
constraint = emptyObjectType;
}

// The constraint may need to be further instantiated with its 'this' type.
constraint = getTypeWithThisArgument(constraint);
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@sandersn sandersn Feb 29, 2016

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Let me check my understanding: an unconstrained type parameter gets 'any' or '{}' as its constraint, which shouldn't have a this-type, so this is a no-op there. Am I right?

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@DanielRosenwasser DanielRosenwasser Feb 29, 2016

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Yup. I could have introduced an else branch, but I figured that this would be a little simpler to read. I'm open to changing it.

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@sandersn sandersn Feb 29, 2016

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No, I think it's fine. Just checking.

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@ahejlsberg ahejlsberg Feb 29, 2016

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You want to instantiate the constraint with source as the this-type parameter, so this line should be:

constraint = getTypeWithThisArgument(constraint, source);

As you have it now you're instantiating the constraint with its own this-type as the this-type parameter. I think the reason it works with the example in the bug is because the this-type of Something is assignable to the this-type of Bar, but it's not the right solution.


// Report constraint errors only if the constraint is not the empty object type
const reportConstraintErrors = reportErrors && constraint !== emptyObjectType;
if (result = isRelatedTo(constraint, target, reportConstraintErrors)) {
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2 changes: 0 additions & 2 deletions tests/baselines/reference/fuzzy.errors.txt
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Expand Up @@ -4,7 +4,6 @@ tests/cases/compiler/fuzzy.ts(21,20): error TS2322: Type '{ anything: number; on
Types of property 'oneI' are incompatible.
Type 'this' is not assignable to type 'I'.
Type 'C' is not assignable to type 'I'.
Property 'alsoWorks' is missing in type 'C'.
tests/cases/compiler/fuzzy.ts(25,20): error TS2352: Neither type '{ oneI: this; }' nor type 'R' is assignable to the other.
Property 'anything' is missing in type '{ oneI: this; }'.

Expand Down Expand Up @@ -39,7 +38,6 @@ tests/cases/compiler/fuzzy.ts(25,20): error TS2352: Neither type '{ oneI: this;
!!! error TS2322: Types of property 'oneI' are incompatible.
!!! error TS2322: Type 'this' is not assignable to type 'I'.
!!! error TS2322: Type 'C' is not assignable to type 'I'.
!!! error TS2322: Property 'alsoWorks' is missing in type 'C'.
}

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@sandersn sandersn Feb 29, 2016

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Why does this go away? We instantiate this as 'C', then somehow we don't notice that alsoWorks is missing now?

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@DanielRosenwasser DanielRosenwasser Feb 29, 2016

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I'm not 100% sure, but I have some thoughts which we can discuss offline.

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@sandersn sandersn Feb 29, 2016

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Here's the result of the offline discussion:
The error's already elaborated at line 26. So now that this is instantiated as C, the compiler knows that it's already reported this error once. (We think :) So it's fine to drop it here.

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@ahejlsberg ahejlsberg Feb 29, 2016

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Yes, this looks like a case of an elaboration that was already made and subsequently cached.

worksToo():R {
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27 changes: 27 additions & 0 deletions tests/baselines/reference/recurringTypeParamForContainerOfBase01.js
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@@ -0,0 +1,27 @@
//// [recurringTypeParamForContainerOfBase01.ts]

interface BoxOfFoo<T extends Foo<T>> {
item: T
}

interface Foo<T extends Foo<T>> {
self: T;
}

interface Bar<T extends Bar<T>> extends Foo<T> {
other: BoxOfFoo<T>;
}

//// [recurringTypeParamForContainerOfBase01.js]


//// [recurringTypeParamForContainerOfBase01.d.ts]
interface BoxOfFoo<T extends Foo<T>> {
item: T;
}
interface Foo<T extends Foo<T>> {
self: T;
}
interface Bar<T extends Bar<T>> extends Foo<T> {
other: BoxOfFoo<T>;
}
37 changes: 37 additions & 0 deletions tests/baselines/reference/recurringTypeParamForContainerOfBase01.symbols
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@@ -0,0 +1,37 @@
=== tests/cases/conformance/types/typeParameters/recurringTypeParamForContainerOfBase01.ts ===

interface BoxOfFoo<T extends Foo<T>> {
>BoxOfFoo : Symbol(BoxOfFoo, Decl(recurringTypeParamForContainerOfBase01.ts, 0, 0))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 1, 19))
>Foo : Symbol(Foo, Decl(recurringTypeParamForContainerOfBase01.ts, 3, 1))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 1, 19))

item: T
>item : Symbol(item, Decl(recurringTypeParamForContainerOfBase01.ts, 1, 38))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 1, 19))
}

interface Foo<T extends Foo<T>> {
>Foo : Symbol(Foo, Decl(recurringTypeParamForContainerOfBase01.ts, 3, 1))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 5, 14))
>Foo : Symbol(Foo, Decl(recurringTypeParamForContainerOfBase01.ts, 3, 1))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 5, 14))

self: T;
>self : Symbol(self, Decl(recurringTypeParamForContainerOfBase01.ts, 5, 33))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 5, 14))
}

interface Bar<T extends Bar<T>> extends Foo<T> {
>Bar : Symbol(Bar, Decl(recurringTypeParamForContainerOfBase01.ts, 7, 1))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 9, 14))
>Bar : Symbol(Bar, Decl(recurringTypeParamForContainerOfBase01.ts, 7, 1))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 9, 14))
>Foo : Symbol(Foo, Decl(recurringTypeParamForContainerOfBase01.ts, 3, 1))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 9, 14))

other: BoxOfFoo<T>;
>other : Symbol(other, Decl(recurringTypeParamForContainerOfBase01.ts, 9, 48))
>BoxOfFoo : Symbol(BoxOfFoo, Decl(recurringTypeParamForContainerOfBase01.ts, 0, 0))
>T : Symbol(T, Decl(recurringTypeParamForContainerOfBase01.ts, 9, 14))
}
37 changes: 37 additions & 0 deletions tests/baselines/reference/recurringTypeParamForContainerOfBase01.types
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@@ -0,0 +1,37 @@
=== tests/cases/conformance/types/typeParameters/recurringTypeParamForContainerOfBase01.ts ===

interface BoxOfFoo<T extends Foo<T>> {
>BoxOfFoo : BoxOfFoo<T>
>T : T
>Foo : Foo<T>
>T : T

item: T
>item : T
>T : T
}

interface Foo<T extends Foo<T>> {
>Foo : Foo<T>
>T : T
>Foo : Foo<T>
>T : T

self: T;
>self : T
>T : T
}

interface Bar<T extends Bar<T>> extends Foo<T> {
>Bar : Bar<T>
>T : T
>Bar : Bar<T>
>T : T
>Foo : Foo<T>
>T : T

other: BoxOfFoo<T>;
>other : BoxOfFoo<T>
>BoxOfFoo : BoxOfFoo<T>
>T : T
}
27 changes: 27 additions & 0 deletions tests/baselines/reference/thisTypeInBasePropertyAndDerivedContainerOfBase01.js
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@@ -0,0 +1,27 @@
//// [thisTypeInBasePropertyAndDerivedContainerOfBase01.ts]

interface BoxOfFoo<T extends Foo> {
item: T
}

interface Foo {
self: this;
}

interface Bar extends Foo {
other: BoxOfFoo<this>;
}

//// [thisTypeInBasePropertyAndDerivedContainerOfBase01.js]


//// [thisTypeInBasePropertyAndDerivedContainerOfBase01.d.ts]
interface BoxOfFoo<T extends Foo> {
item: T;
}
interface Foo {
self: this;
}
interface Bar extends Foo {
other: BoxOfFoo<this>;
}
27 changes: 27 additions & 0 deletions tests/baselines/reference/thisTypeInBasePropertyAndDerivedContainerOfBase01.symbols
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@@ -0,0 +1,27 @@
=== tests/cases/conformance/types/thisType/thisTypeInBasePropertyAndDerivedContainerOfBase01.ts ===

interface BoxOfFoo<T extends Foo> {
>BoxOfFoo : Symbol(BoxOfFoo, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 0, 0))
>T : Symbol(T, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 1, 19))
>Foo : Symbol(Foo, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 3, 1))

item: T
>item : Symbol(item, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 1, 35))
>T : Symbol(T, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 1, 19))
}

interface Foo {
>Foo : Symbol(Foo, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 3, 1))

self: this;
>self : Symbol(self, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 5, 15))
}

interface Bar extends Foo {
>Bar : Symbol(Bar, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 7, 1))
>Foo : Symbol(Foo, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 3, 1))

other: BoxOfFoo<this>;
>other : Symbol(other, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 9, 27))
>BoxOfFoo : Symbol(BoxOfFoo, Decl(thisTypeInBasePropertyAndDerivedContainerOfBase01.ts, 0, 0))
}
27 changes: 27 additions & 0 deletions tests/baselines/reference/thisTypeInBasePropertyAndDerivedContainerOfBase01.types
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@@ -0,0 +1,27 @@
=== tests/cases/conformance/types/thisType/thisTypeInBasePropertyAndDerivedContainerOfBase01.ts ===

interface BoxOfFoo<T extends Foo> {
>BoxOfFoo : BoxOfFoo<T>
>T : T
>Foo : Foo

item: T
>item : T
>T : T
}

interface Foo {
>Foo : Foo

self: this;
>self : this
}

interface Bar extends Foo {
>Bar : Bar
>Foo : Foo

other: BoxOfFoo<this>;
>other : BoxOfFoo<this>
>BoxOfFoo : BoxOfFoo<T>
}
13 changes: 13 additions & 0 deletions tests/cases/conformance/types/thisType/thisTypeInBasePropertyAndDerivedContainerOfBase01.ts
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@@ -0,0 +1,13 @@
// @declaration: true

interface BoxOfFoo<T extends Foo> {
item: T
}

interface Foo {
self: this;
}

interface Bar extends Foo {
other: BoxOfFoo<this>;
}
13 changes: 13 additions & 0 deletions tests/cases/conformance/types/typeParameters/recurringTypeParamForContainerOfBase01.ts
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@@ -0,0 +1,13 @@
// @declaration: true

interface BoxOfFoo<T extends Foo<T>> {
item: T
}

interface Foo<T extends Foo<T>> {
self: T;
}

interface Bar<T extends Bar<T>> extends Foo<T> {
other: BoxOfFoo<T>;
}