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Merged
sandersn merged 13 commits into from
Jun 4, 2018
Merged

Template tag allows specification of constraints #24600

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b208b4f
Parse (and mostly support) template tag constraints
sandersn May 31, 2018
e986333
Messy version is finished. Need to add a few tests
sandersn Jun 1, 2018
e629fc9
Refactor to be smaller
sandersn Jun 1, 2018
da9f937
Small refactor + Add one test
sandersn Jun 1, 2018
24fdef6
Another test
sandersn Jun 1, 2018
efd8a4f
Minor cleanup
sandersn Jun 1, 2018
d499fde
Fix error reporting on type parameters on ctors
sandersn Jun 1, 2018
781bc65
Simplify syntax of `@template` tag
sandersn Jun 1, 2018
e5e9e43
Better error message for template tag
sandersn Jun 2, 2018
f6d56f3
Fix fourslash baselines
sandersn Jun 2, 2018
0019f69
Another fourslash update
sandersn Jun 3, 2018
3ce4b24
Address PR comments
sandersn Jun 4, 2018
e85d472
Simplify getEffectiveTypeParameterDeclarations
sandersn Jun 4, 2018
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4 changes: 2 additions & 2 deletions src/compiler/checker.ts
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Expand Up @@ -28417,8 +28417,8 @@ namespace ts {

function checkGrammarConstructorTypeParameters(node: ConstructorDeclaration) {
const typeParameters = getEffectiveTypeParameterDeclarations(node);
if (isNodeArray(typeParameters)) {
const { pos, end } = typeParameters;
if (isNodeArray(typeParameters) || typeParameters.length) {
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@mhegazy mhegazy Jun 4, 2018

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when is it not a NodeArray?

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@sandersn sandersn Jun 4, 2018

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getEffectiveTypeParameterDeclarations returns a ReadonlyArray now. Previously it returned templateTags[0].typeParameters, which was a NodeArray. Now it returns flatMap(templateTags, t => t.typeParameters), which is a ReadonlyArray.

I don't think it's worth the trouble to create a NodeArray because the resulting span would stretch across all 3 template tags below, which is very ugly:

/** @template T
* @template U
* @template V
*/
constructor() { }

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@mhegazy mhegazy Jun 4, 2018

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in the past we stuck a pos and an end on the result to make it look like a NodeArray.. why can not we do the same here?

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@mhegazy mhegazy Jun 4, 2018

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actually looking at the code, that is exactly what we do.. it looks like it will always be a NodeArray

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@sandersn sandersn Jun 4, 2018

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In getEffectiveTypeParameterDeclarations, the code path that calls getJSDocTypeParameterDeclarations ends up calling flatMap, which is what returns the non-NodeArray:

    /**
     * Gets the effective type parameters. If the node was parsed in a
     * JavaScript file, gets the type parameters from the `@template` tag from JSDoc.
     */
    export function getEffectiveTypeParameterDeclarations(node: DeclarationWithTypeParameters): ReadonlyArray<TypeParameterDeclaration> {
        if (isJSDocSignature(node)) {
            return emptyArray; /*** Not a NodeArray ***/
        }
        if (isJSDocTypeAlias(node)) {
            Debug.assert(node.parent.kind === SyntaxKind.JSDocComment);
            const templateTags = flatMap(filter(node.parent.tags, isJSDocTemplateTag), tag => tag.typeParameters) as ReadonlyArray<TypeParameterDeclaration>;
            const templateTagNodes = templateTags as NodeArray<TypeParameterDeclaration>;
            templateTagNodes.pos = templateTagNodes.length > 0 ? first(templateTagNodes).pos : node.pos;
            templateTagNodes.end = templateTagNodes.length > 0 ? last(templateTagNodes).end : node.end;
            templateTagNodes.hasTrailingComma = false;
            return templateTagNodes;
        }
        return node.typeParameters || (isInJavaScriptFile(node) ? getJSDocTypeParameterDeclarations(node) : emptyArray);
    }

    export function getJSDocTypeParameterDeclarations(node: DeclarationWithTypeParameters): ReadonlyArray<TypeParameterDeclaration> {
        /*** flatMap does not return a NodeArray ***/
        return flatMap(getJSDocTags(node), tag => isNonTypeAliasTemplate(tag) ? tag.typeParameters : undefined);
    }

The jsdoc signature case returns emptyArray, which is also not a NodeArray.

const { pos, end } = isNodeArray(typeParameters) ? typeParameters : typeParameters[0];
return grammarErrorAtPos(node, pos, end - pos, Diagnostics.Type_parameters_cannot_appear_on_a_constructor_declaration);
}
}
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4 changes: 4 additions & 0 deletions src/compiler/diagnosticMessages.json
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Expand Up @@ -219,6 +219,10 @@
"category": "Error",
"code": 1068
},
"Unexpected token. A type parameter name was expected without curly braces.": {
"category": "Error",
"code": 1069
},
"'{0}' modifier cannot appear on a type member.": {
"category": "Error",
"code": 1070
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35 changes: 14 additions & 21 deletions src/compiler/parser.ts
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Expand Up @@ -7013,29 +7013,27 @@ namespace ts {
}

function parseTemplateTag(atToken: AtToken, tagName: Identifier): JSDocTemplateTag | undefined {
if (some(tags, isJSDocTemplateTag)) {
parseErrorAt(tagName.pos, scanner.getTokenPos(), Diagnostics._0_tag_already_specified, tagName.escapedText);
// the template tag looks like '@template {Constraint} T,U,V'
let constraint: JSDocTypeExpression | undefined;
if (token() === SyntaxKind.OpenBraceToken) {
constraint = parseJSDocTypeExpression();
skipWhitespace();
}

// Type parameter list looks like '@template T,U,V'
const typeParameters = [];
const typeParametersPos = getNodePos();

while (true) {
const typeParameter = <TypeParameterDeclaration>createNode(SyntaxKind.TypeParameter);
const name = parseJSDocIdentifierNameWithOptionalBraces();
skipWhitespace();
if (!name) {
parseErrorAtPosition(scanner.getStartPos(), 0, Diagnostics.Identifier_expected);
if (!tokenIsIdentifierOrKeyword(token())) {
parseErrorAtCurrentToken(Diagnostics.Unexpected_token_A_type_parameter_name_was_expected_without_curly_braces);
return undefined;
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Was already this way, but it looks like parseTemplateTag is the only tag-parsing method out of 9 that can return undefined. Might be better to call parseJSDocIdentifierName with createIfMissing set, and a new parameter to allow a custom diagnostic. Than parseTag could return JSDocTag (without | undefined).

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@sandersn sandersn Jun 4, 2018

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parseTag returns undefined near the beginning if it can't parseJSDocIdentifierName, too. As-is the change is not worth it in my opinion. It might be worthwhile to have parseJSDocIdentifierName always return a missing node. I tried that and it looks a bit better, but there's a good bit of churn. Would you like to review it as part of this PR or would you like to see it in a separate one?

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Separate is good.

}

typeParameter.name = name;
typeParameter.name = parseJSDocIdentifierName()!;
skipWhitespace();
finishNode(typeParameter);

typeParameters.push(typeParameter);

if (token() === SyntaxKind.CommaToken) {
// need to look for more type parameters
nextJSDocToken();
skipWhitespace();
}
Expand All @@ -7044,6 +7042,10 @@ namespace ts {
}
}

if (constraint) {
first(typeParameters).constraint = constraint.type;
}

const result = <JSDocTemplateTag>createNode(SyntaxKind.JSDocTemplateTag, atToken.pos);
result.atToken = atToken;
result.tagName = tagName;
Expand All @@ -7052,15 +7054,6 @@ namespace ts {
return result;
}

function parseJSDocIdentifierNameWithOptionalBraces(): Identifier | undefined {
const parsedBrace = parseOptional(SyntaxKind.OpenBraceToken);
const res = parseJSDocIdentifierName();
if (parsedBrace) {
parseExpected(SyntaxKind.CloseBraceToken);
}
return res;
}

function nextJSDocToken(): JsDocSyntaxKind {
return currentToken = scanner.scanJSDocToken();
}
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10 changes: 6 additions & 4 deletions src/compiler/utilities.ts
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Expand Up @@ -3177,10 +3177,12 @@ namespace ts {
}

export function getJSDocTypeParameterDeclarations(node: DeclarationWithTypeParameters): ReadonlyArray<TypeParameterDeclaration> {
// template tags are only available when a typedef isn't already using them
const tag = find(getJSDocTags(node), (tag): tag is JSDocTemplateTag =>
isJSDocTemplateTag(tag) && !(tag.parent.kind === SyntaxKind.JSDocComment && tag.parent.tags!.some(isJSDocTypeAlias)));
return (tag && tag.typeParameters) || emptyArray;
return flatMap(getJSDocTags(node), tag => isNonTypeAliasTemplate(tag) ? tag.typeParameters : undefined);
}

/** template tags are only available when a typedef isn't already using them */
function isNonTypeAliasTemplate(tag: JSDocTag): tag is JSDocTemplateTag {
return isJSDocTemplateTag(tag) && !(tag.parent.kind === SyntaxKind.JSDocComment && tag.parent.tags!.some(isJSDocTypeAlias));
}

/**
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2 changes: 1 addition & 1 deletion tests/baselines/reference/jsdocTemplateClass.errors.txt
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Expand Up @@ -3,7 +3,7 @@ tests/cases/conformance/jsdoc/templateTagOnClasses.js(25,1): error TS2322: Type

==== tests/cases/conformance/jsdoc/templateTagOnClasses.js (1 errors) ====
/**
* @template {T}
* @template T
* @typedef {(t: T) => T} Id
*/
/** @template T */
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2 changes: 1 addition & 1 deletion tests/baselines/reference/jsdocTemplateClass.symbols
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@@ -1,6 +1,6 @@
=== tests/cases/conformance/jsdoc/templateTagOnClasses.js ===
/**
* @template {T}
* @template T
* @typedef {(t: T) => T} Id
*/
/** @template T */
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2 changes: 1 addition & 1 deletion tests/baselines/reference/jsdocTemplateClass.types
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@@ -1,6 +1,6 @@
=== tests/cases/conformance/jsdoc/templateTagOnClasses.js ===
/**
* @template {T}
* @template T
* @typedef {(t: T) => T} Id
*/
/** @template T */
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4 changes: 2 additions & 2 deletions tests/baselines/reference/jsdocTemplateConstructorFunction.errors.txt
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Expand Up @@ -3,12 +3,12 @@ tests/cases/conformance/jsdoc/templateTagOnConstructorFunctions.js(24,1): error

==== tests/cases/conformance/jsdoc/templateTagOnConstructorFunctions.js (1 errors) ====
/**
* @template {U}
* @template U
* @typedef {(u: U) => U} Id
*/
/**
* @param {T} t
* @template {T}
* @template T
*/
function Zet(t) {
/** @type {T} */
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4 changes: 2 additions & 2 deletions tests/baselines/reference/jsdocTemplateConstructorFunction.symbols
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@@ -1,11 +1,11 @@
=== tests/cases/conformance/jsdoc/templateTagOnConstructorFunctions.js ===
/**
* @template {U}
* @template U
* @typedef {(u: U) => U} Id
*/
/**
* @param {T} t
* @template {T}
* @template T
*/
function Zet(t) {
>Zet : Symbol(Zet, Decl(templateTagOnConstructorFunctions.js, 0, 0))
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4 changes: 2 additions & 2 deletions tests/baselines/reference/jsdocTemplateConstructorFunction.types
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@@ -1,11 +1,11 @@
=== tests/cases/conformance/jsdoc/templateTagOnConstructorFunctions.js ===
/**
* @template {U}
* @template U
* @typedef {(u: U) => U} Id
*/
/**
* @param {T} t
* @template {T}
* @template T
*/
function Zet(t) {
>Zet : typeof Zet
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2 changes: 1 addition & 1 deletion tests/baselines/reference/jsdocTemplateConstructorFunction2.errors.txt
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Expand Up @@ -5,7 +5,7 @@ tests/cases/conformance/jsdoc/templateTagWithNestedTypeLiteral.js(26,15): error
==== tests/cases/conformance/jsdoc/templateTagWithNestedTypeLiteral.js (2 errors) ====
/**
* @param {T} t
* @template {T}
* @template T
*/
function Zet(t) {
/** @type {T} */
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2 changes: 1 addition & 1 deletion tests/baselines/reference/jsdocTemplateConstructorFunction2.symbols
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@@ -1,7 +1,7 @@
=== tests/cases/conformance/jsdoc/templateTagWithNestedTypeLiteral.js ===
/**
* @param {T} t
* @template {T}
* @template T
*/
function Zet(t) {
>Zet : Symbol(Zet, Decl(templateTagWithNestedTypeLiteral.js, 0, 0))
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2 changes: 1 addition & 1 deletion tests/baselines/reference/jsdocTemplateConstructorFunction2.types
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@@ -1,7 +1,7 @@
=== tests/cases/conformance/jsdoc/templateTagWithNestedTypeLiteral.js ===
/**
* @param {T} t
* @template {T}
* @template T
*/
function Zet(t) {
>Zet : typeof Zet
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47 changes: 47 additions & 0 deletions tests/baselines/reference/jsdocTemplateTag3.errors.txt
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@@ -0,0 +1,47 @@
tests/cases/conformance/jsdoc/a.js(14,29): error TS2339: Property 'a' does not exist on type 'U'.
tests/cases/conformance/jsdoc/a.js(14,35): error TS2339: Property 'b' does not exist on type 'U'.
tests/cases/conformance/jsdoc/a.js(21,3): error TS2345: Argument of type '{ a: number; }' is not assignable to parameter of type '{ a: number; b: string; }'.
Property 'b' is missing in type '{ a: number; }'.
tests/cases/conformance/jsdoc/a.js(25,2): error TS1069: Unexpected token. A type parameter name was expected without curly braces.


==== tests/cases/conformance/jsdoc/a.js (4 errors) ====
/**
* @template {{ a: number, b: string }} T,U A Comment
* @template {{ c: boolean }} V uh ... are comments even supported??
* @template W
* @template X That last one had no comment
* @param {T} t
* @param {U} u
* @param {V} v
* @param {W} w
* @param {X} x
* @return {W | X}
*/
function f(t, u, v, w, x) {
if(t.a + t.b.length > u.a - u.b.length && v.c) {
~
!!! error TS2339: Property 'a' does not exist on type 'U'.
~
!!! error TS2339: Property 'b' does not exist on type 'U'.
return w;
}
return x;
}

f({ a: 12, b: 'hi', c: null }, undefined, { c: false, d: 12, b: undefined }, 101, 'nope');
f({ a: 12 }, undefined, undefined, 101, 'nope');
~~~~~~~~~~
!!! error TS2345: Argument of type '{ a: number; }' is not assignable to parameter of type '{ a: number; b: string; }'.
!!! error TS2345: Property 'b' is missing in type '{ a: number; }'.

/**
* @template {NoLongerAllowed}
* @template T preceding line's syntax is no longer allowed
~
!!! error TS1069: Unexpected token. A type parameter name was expected without curly braces.
* @param {T} x
*/
function g(x) { }


70 changes: 70 additions & 0 deletions tests/baselines/reference/jsdocTemplateTag3.symbols
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@@ -0,0 +1,70 @@
=== tests/cases/conformance/jsdoc/a.js ===
/**
* @template {{ a: number, b: string }} T,U A Comment
* @template {{ c: boolean }} V uh ... are comments even supported??
* @template W
* @template X That last one had no comment
* @param {T} t
* @param {U} u
* @param {V} v
* @param {W} w
* @param {X} x
* @return {W | X}
*/
function f(t, u, v, w, x) {
>f : Symbol(f, Decl(a.js, 0, 0))
>t : Symbol(t, Decl(a.js, 12, 11))
>u : Symbol(u, Decl(a.js, 12, 13))
>v : Symbol(v, Decl(a.js, 12, 16))
>w : Symbol(w, Decl(a.js, 12, 19))
>x : Symbol(x, Decl(a.js, 12, 22))

if(t.a + t.b.length > u.a - u.b.length && v.c) {
>t.a : Symbol(a, Decl(a.js, 1, 15))
>t : Symbol(t, Decl(a.js, 12, 11))
>a : Symbol(a, Decl(a.js, 1, 15))
>t.b.length : Symbol(String.length, Decl(lib.d.ts, --, --))
>t.b : Symbol(b, Decl(a.js, 1, 26))
>t : Symbol(t, Decl(a.js, 12, 11))
>b : Symbol(b, Decl(a.js, 1, 26))
>length : Symbol(String.length, Decl(lib.d.ts, --, --))
>u : Symbol(u, Decl(a.js, 12, 13))
>u : Symbol(u, Decl(a.js, 12, 13))
>v.c : Symbol(c, Decl(a.js, 2, 15))
>v : Symbol(v, Decl(a.js, 12, 16))
>c : Symbol(c, Decl(a.js, 2, 15))

return w;
>w : Symbol(w, Decl(a.js, 12, 19))
}
return x;
>x : Symbol(x, Decl(a.js, 12, 22))
}

f({ a: 12, b: 'hi', c: null }, undefined, { c: false, d: 12, b: undefined }, 101, 'nope');
>f : Symbol(f, Decl(a.js, 0, 0))
>a : Symbol(a, Decl(a.js, 19, 3))
>b : Symbol(b, Decl(a.js, 19, 10))
>c : Symbol(c, Decl(a.js, 19, 19))
>undefined : Symbol(undefined)
>c : Symbol(c, Decl(a.js, 19, 43))
>d : Symbol(d, Decl(a.js, 19, 53))
>b : Symbol(b, Decl(a.js, 19, 60))
>undefined : Symbol(undefined)

f({ a: 12 }, undefined, undefined, 101, 'nope');
>f : Symbol(f, Decl(a.js, 0, 0))
>a : Symbol(a, Decl(a.js, 20, 3))
>undefined : Symbol(undefined)
>undefined : Symbol(undefined)

/**
* @template {NoLongerAllowed}
* @template T preceding line's syntax is no longer allowed
* @param {T} x
*/
function g(x) { }
>g : Symbol(g, Decl(a.js, 20, 49))
>x : Symbol(x, Decl(a.js, 27, 11))


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