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Preserve original type parameter names more often when shadowed #55820

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Merged
merged 6 commits into from
Nov 6, 2023
Merged

Preserve original type parameter names more often when shadowed #55820

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a1df1ae
Add test
jakebailey Sep 8, 2023
ae91031
Add interesting test from other bug investigation
jakebailey Sep 22, 2023
d8caed4
Add new test case which breaks with this code
jakebailey Sep 24, 2023
d13fa94
Add test case from PR 56046
jakebailey Oct 9, 2023
abb71e9
Use fake scopes for type parameters too, and other needed changes
jakebailey Sep 21, 2023
4abb747
Empty commit to retrigger CI
jakebailey Nov 6, 2023
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85 changes: 58 additions & 27 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -6623,8 +6623,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
}
if (
context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams &&
type.flags & TypeFlags.TypeParameter &&
!isTypeSymbolAccessible(type.symbol, context.enclosingDeclaration)
type.flags & TypeFlags.TypeParameter
) {
const name = typeParameterToName(type, context);
context.approximateLength += idText(name).length;
Expand Down Expand Up @@ -7527,7 +7526,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
&& signature.declaration
&& signature.declaration !== context.enclosingDeclaration
&& !isInJSFile(signature.declaration)
&& some(expandedParams)
&& (some(expandedParams) || some(signature.typeParameters))
) {
// As a performance optimization, reuse the same fake scope within this chain.
// This is especially needed when we are working on an excessively deep type;
Expand All @@ -7545,32 +7544,64 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
// Note that we only check the most immediate enclosingDeclaration; the only place we
// could potentially add another fake scope into the chain is right here, so we don't
// traverse all ancestors.
const existingFakeScope = getNodeLinks(context.enclosingDeclaration).fakeScopeForSignatureDeclaration ? context.enclosingDeclaration : undefined;
Debug.assertOptionalNode(existingFakeScope, isBlock);
pushFakeScope(
"params",
add => {
for (const param of expandedParams) {
add(param.escapedName, param);
}
},
);

const locals = existingFakeScope?.locals ?? createSymbolTable();
if (context.flags & NodeBuilderFlags.GenerateNamesForShadowedTypeParams) {
// TODO(jakebailey): should this instead be done before walking type parameters?
pushFakeScope(
"typeParams",
add => {
for (const typeParam of signature.typeParameters ?? emptyArray) {
const typeParamName = typeParameterToName(typeParam, context).escapedText;
add(typeParamName, typeParam.symbol);
}
},
);
}

let newLocals: __String[] | undefined;
for (const param of expandedParams) {
if (!locals.has(param.escapedName)) {
newLocals = append(newLocals, param.escapedName);
locals.set(param.escapedName, param);
function pushFakeScope(kind: "params" | "typeParams", addAll: (addSymbol: (name: __String, symbol: Symbol) => void) => void) {
// We only ever need to look two declarations upward.
Debug.assert(context.enclosingDeclaration);
let existingFakeScope: Node | undefined;
if (getNodeLinks(context.enclosingDeclaration).fakeScopeForSignatureDeclaration === kind) {
existingFakeScope = context.enclosingDeclaration;
}
}
else if (context.enclosingDeclaration.parent && getNodeLinks(context.enclosingDeclaration.parent).fakeScopeForSignatureDeclaration === kind) {
existingFakeScope = context.enclosingDeclaration.parent;
}
Debug.assertOptionalNode(existingFakeScope, isBlock);

if (newLocals) {
function removeNewLocals() {
const locals = existingFakeScope?.locals ?? createSymbolTable();
let newLocals: __String[] | undefined;
addAll((name, symbol) => {
if (!locals.has(name)) {
newLocals = append(newLocals, name);
locals.set(name, symbol);
}
});
if (!newLocals) return;

const oldCleanup = cleanup;
function undo() {
forEach(newLocals, s => locals.delete(s));
oldCleanup?.();
}

if (existingFakeScope) {
cleanup = removeNewLocals;
cleanup = undo;
}
else {
// Use a Block for this; the type of the node doesn't matter so long as it
// has locals, and this is cheaper/easier than using a function-ish Node.
const fakeScope = parseNodeFactory.createBlock(emptyArray);
getNodeLinks(fakeScope).fakeScopeForSignatureDeclaration = true;
getNodeLinks(fakeScope).fakeScopeForSignatureDeclaration = kind;
fakeScope.locals = locals;

const saveEnclosingDeclaration = context.enclosingDeclaration;
Expand All @@ -7579,7 +7610,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {

cleanup = () => {
context.enclosingDeclaration = saveEnclosingDeclaration;
removeNewLocals();
undo();
};
}
}
Expand Down Expand Up @@ -8127,13 +8158,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
}
}

function typeParameterShadowsNameInScope(escapedName: __String, context: NodeBuilderContext, type: TypeParameter) {
function typeParameterShadowsOtherTypeParameterInScope(escapedName: __String, context: NodeBuilderContext, type: TypeParameter) {
const result = resolveName(context.enclosingDeclaration, escapedName, SymbolFlags.Type, /*nameNotFoundMessage*/ undefined, escapedName, /*isUse*/ false);
if (result) {
if (result.flags & SymbolFlags.TypeParameter && result === type.symbol) {
return false;
}
return true;
if (result && result.flags & SymbolFlags.TypeParameter) {
return result !== type.symbol;
}
return false;
}
Expand All @@ -8153,7 +8181,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
const rawtext = result.escapedText as string;
let i = context.typeParameterNamesByTextNextNameCount?.get(rawtext) || 0;
let text = rawtext;
while (context.typeParameterNamesByText?.has(text) || typeParameterShadowsNameInScope(text as __String, context, type)) {
while (context.typeParameterNamesByText?.has(text) || typeParameterShadowsOtherTypeParameterInScope(text as __String, context, type)) {
i++;
text = `${rawtext}_${i}`;
}
Expand All @@ -8166,7 +8194,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
// `i` we've used thus far, to save work later
(context.typeParameterNamesByTextNextNameCount ||= new Map()).set(rawtext, i);
(context.typeParameterNames ||= new Map()).set(getTypeId(type), result);
(context.typeParameterNamesByText ||= new Set()).add(rawtext);
(context.typeParameterNamesByText ||= new Set()).add(text);
}
return result;
}
Expand Down Expand Up @@ -8345,7 +8373,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
}

function getEnclosingDeclarationIgnoringFakeScope(enclosingDeclaration: Node) {
return getNodeLinks(enclosingDeclaration).fakeScopeForSignatureDeclaration ? enclosingDeclaration.parent : enclosingDeclaration;
while (getNodeLinks(enclosingDeclaration).fakeScopeForSignatureDeclaration) {
enclosingDeclaration = enclosingDeclaration.parent;
}
return enclosingDeclaration;
}

/**
Expand Down Expand Up @@ -8425,7 +8456,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
}
if (isIdentifier(node)) {
const type = getDeclaredTypeOfSymbol(sym);
const name = sym.flags & SymbolFlags.TypeParameter && !isTypeSymbolAccessible(type.symbol, context.enclosingDeclaration) ? typeParameterToName(type, context) : factory.cloneNode(node);
const name = sym.flags & SymbolFlags.TypeParameter ? typeParameterToName(type, context) : factory.cloneNode(node);
name.symbol = sym; // for quickinfo, which uses identifier symbol information
return { introducesError, node: setEmitFlags(setOriginalNode(name, node), EmitFlags.NoAsciiEscaping) };
}
Expand Down
2 changes: 1 addition & 1 deletion src/compiler/types.ts
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Expand Up @@ -6047,7 +6047,7 @@ export interface NodeLinks {
decoratorSignature?: Signature; // Signature for decorator as if invoked by the runtime.
spreadIndices?: { first: number | undefined, last: number | undefined }; // Indices of first and last spread elements in array literal
parameterInitializerContainsUndefined?: boolean; // True if this is a parameter declaration whose type annotation contains "undefined".
fakeScopeForSignatureDeclaration?: boolean; // True if this is a fake scope injected into an enclosing declaration chain.
fakeScopeForSignatureDeclaration?: "params" | "typeParams"; // If present, this is a fake scope injected into an enclosing declaration chain.
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Not sure if this should be an enum, I just used a string here as the least annoying way to get two truthy values.

assertionExpressionType?: Type; // Cached type of the expression of a type assertion
}

Expand Down
8 changes: 4 additions & 4 deletions tests/baselines/reference/assignmentCompatWithCallSignatures.types
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Expand Up @@ -56,9 +56,9 @@ a = a2;
>a2 : (x: number) => string

t = <T>(x: T) => 1;
>t = <T>(x: T) => 1 : <T_1>(x: T_1) => number
>t = <T>(x: T) => 1 : <T>(x: T) => number
>t : T
><T>(x: T) => 1 : <T_1>(x: T_1) => number
><T>(x: T) => 1 : <T>(x: T) => number
>x : T
>1 : 1

Expand All @@ -76,9 +76,9 @@ t = function (x: number) { return ''; }
>'' : ""

a = <T>(x: T) => 1;
>a = <T>(x: T) => 1 : <T_1>(x: T_1) => number
>a = <T>(x: T) => 1 : <T>(x: T) => number
>a : (x: number) => void
><T>(x: T) => 1 : <T_1>(x: T_1) => number
><T>(x: T) => 1 : <T>(x: T) => number
>x : T
>1 : 1

Expand Down
16 changes: 8 additions & 8 deletions tests/baselines/reference/assignmentCompatWithCallSignatures2.types
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Expand Up @@ -68,11 +68,11 @@ t = { f: () => 1 };
>1 : 1

t = { f: <T>(x:T) => 1 };
>t = { f: <T>(x:T) => 1 } : { f: <T_1>(x: T_1) => number; }
>t = { f: <T>(x:T) => 1 } : { f: <T>(x: T) => number; }
>t : T
>{ f: <T>(x:T) => 1 } : { f: <T_1>(x: T_1) => number; }
>f : <T_1>(x: T_1) => number
><T>(x:T) => 1 : <T_1>(x: T_1) => number
>{ f: <T>(x:T) => 1 } : { f: <T>(x: T) => number; }
>f : <T>(x: T) => number
><T>(x:T) => 1 : <T>(x: T) => number
>x : T
>1 : 1

Expand Down Expand Up @@ -102,11 +102,11 @@ a = { f: () => 1 }
>1 : 1

a = { f: <T>(x: T) => 1 };
>a = { f: <T>(x: T) => 1 } : { f: <T_1>(x: T_1) => number; }
>a = { f: <T>(x: T) => 1 } : { f: <T>(x: T) => number; }
>a : { f(x: number): void; }
>{ f: <T>(x: T) => 1 } : { f: <T_1>(x: T_1) => number; }
>f : <T_1>(x: T_1) => number
><T>(x: T) => 1 : <T_1>(x: T_1) => number
>{ f: <T>(x: T) => 1 } : { f: <T>(x: T) => number; }
>f : <T>(x: T) => number
><T>(x: T) => 1 : <T>(x: T) => number
>x : T
>1 : 1

Expand Down
2 changes: 1 addition & 1 deletion tests/baselines/reference/assignmentCompatWithCallSignatures3.types
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Expand Up @@ -355,7 +355,7 @@ b13 = a13; // ok
>a13 : (x: Base[], y: Derived[]) => Derived[]

var b14: <T>(x: { a: T; b: T }) => T;
>b14 : <T>(x: { a: T; b: T; }) => T
>b14 : <T>(x: { a: T; b: T;}) => T
>x : { a: T; b: T; }
>a : T
>b : T
Expand Down
4 changes: 2 additions & 2 deletions tests/baselines/reference/assignmentCompatWithCallSignatures4.types
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Expand Up @@ -224,7 +224,7 @@ module Errors {
>a12 : (x: Base[], y: Derived2[]) => Derived[]

var b15: <T>(x: { a: T; b: T }) => T;
>b15 : <T>(x: { a: T; b: T; }) => T
>b15 : <T>(x: { a: T; b: T;}) => T
>x : { a: T; b: T; }
>a : T
>b : T
Expand All @@ -240,7 +240,7 @@ module Errors {
>a15 : (x: { a: string; b: number; }) => number

var b15a: <T extends Base>(x: { a: T; b: T }) => number;
>b15a : <T extends Base>(x: { a: T; b: T; }) => number
>b15a : <T extends Base>(x: { a: T; b: T;}) => number
>x : { a: T; b: T; }
>a : T
>b : T
Expand Down
12 changes: 6 additions & 6 deletions tests/baselines/reference/assignmentCompatWithCallSignatures5.types
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Expand Up @@ -50,21 +50,21 @@ var a6: <T extends Base>(x: (arg: T) => Derived) => T;
>arg : T

var a11: <T>(x: { foo: T }, y: { foo: T; bar: T }) => Base;
>a11 : <T>(x: { foo: T; }, y: { foo: T; bar: T; }) => Base
>a11 : <T>(x: { foo: T;}, y: { foo: T; bar: T;}) => Base
>x : { foo: T; }
>foo : T
>y : { foo: T; bar: T; }
>foo : T
>bar : T

var a15: <T>(x: { a: T; b: T }) => T[];
>a15 : <T>(x: { a: T; b: T; }) => T[]
>a15 : <T>(x: { a: T; b: T;}) => T[]
>x : { a: T; b: T; }
>a : T
>b : T

var a16: <T extends Base>(x: { a: T; b: T }) => T[];
>a16 : <T extends Base>(x: { a: T; b: T; }) => T[]
>a16 : <T extends Base>(x: { a: T; b: T;}) => T[]
>x : { a: T; b: T; }
>a : T
>b : T
Expand Down Expand Up @@ -194,7 +194,7 @@ b6 = a6; // ok
>a6 : <T extends Base>(x: (arg: T) => Derived) => T

var b11: <T, U>(x: { foo: T }, y: { foo: U; bar: U }) => Base;
>b11 : <T, U>(x: { foo: T; }, y: { foo: U; bar: U; }) => Base
>b11 : <T, U>(x: { foo: T;}, y: { foo: U; bar: U;}) => Base
>x : { foo: T; }
>foo : T
>y : { foo: U; bar: U; }
Expand All @@ -212,7 +212,7 @@ b11 = a11; // ok
>a11 : <T>(x: { foo: T; }, y: { foo: T; bar: T; }) => Base

var b15: <U, V>(x: { a: U; b: V; }) => U[];
>b15 : <U, V>(x: { a: U; b: V; }) => U[]
>b15 : <U, V>(x: { a: U; b: V;}) => U[]
>x : { a: U; b: V; }
>a : U
>b : V
Expand All @@ -228,7 +228,7 @@ b15 = a15; // ok
>a15 : <T>(x: { a: T; b: T; }) => T[]

var b16: <T>(x: { a: T; b: T }) => T[];
>b16 : <T>(x: { a: T; b: T; }) => T[]
>b16 : <T>(x: { a: T; b: T;}) => T[]
>x : { a: T; b: T; }
>a : T
>b : T
Expand Down
10 changes: 5 additions & 5 deletions tests/baselines/reference/assignmentCompatWithCallSignatures6.types
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Expand Up @@ -51,21 +51,21 @@ interface A {
>arg : T

a11: <T>(x: { foo: T }, y: { foo: T; bar: T }) => Base;
>a11 : <T>(x: { foo: T; }, y: { foo: T; bar: T; }) => Base
>a11 : <T>(x: { foo: T;}, y: { foo: T; bar: T;}) => Base
>x : { foo: T; }
>foo : T
>y : { foo: T; bar: T; }
>foo : T
>bar : T

a15: <T>(x: { a: T; b: T }) => T[];
>a15 : <T>(x: { a: T; b: T; }) => T[]
>a15 : <T>(x: { a: T; b: T;}) => T[]
>x : { a: T; b: T; }
>a : T
>b : T

a16: <T extends Base>(x: { a: T; b: T }) => T[];
>a16 : <T extends Base>(x: { a: T; b: T; }) => T[]
>a16 : <T extends Base>(x: { a: T; b: T;}) => T[]
>x : { a: T; b: T; }
>a : T
>b : T
Expand Down Expand Up @@ -167,7 +167,7 @@ b5 = x.a5;
>a5 : <T, U>(x: (arg: T) => U) => T

var b11: <T, U>(x: { foo: T }, y: { foo: U; bar: U }) => Base;
>b11 : <T, U>(x: { foo: T; }, y: { foo: U; bar: U; }) => Base
>b11 : <T, U>(x: { foo: T;}, y: { foo: U; bar: U;}) => Base
>x : { foo: T; }
>foo : T
>y : { foo: U; bar: U; }
Expand All @@ -189,7 +189,7 @@ b11 = x.a11;
>a11 : <T>(x: { foo: T; }, y: { foo: T; bar: T; }) => Base

var b16: <T>(x: { a: T; b: T }) => T[];
>b16 : <T>(x: { a: T; b: T; }) => T[]
>b16 : <T>(x: { a: T; b: T;}) => T[]
>x : { a: T; b: T; }
>a : T
>b : T
Expand Down
2 changes: 1 addition & 1 deletion tests/baselines/reference/assignmentCompatWithConstructSignatures3.types
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Expand Up @@ -355,7 +355,7 @@ b13 = a13; // ok
>a13 : new (x: Base[], y: Derived[]) => Derived[]

var b14: new <T>(x: { a: T; b: T }) => T;
>b14 : new <T>(x: { a: T; b: T; }) => T
>b14 : new <T>(x: { a: T; b: T;}) => T
>x : { a: T; b: T; }
>a : T
>b : T
Expand Down
4 changes: 2 additions & 2 deletions tests/baselines/reference/assignmentCompatWithConstructSignatures4.types
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Expand Up @@ -224,7 +224,7 @@ module Errors {
>a12 : new (x: Base[], y: Derived2[]) => Derived[]

var b15: new <T>(x: { a: T; b: T }) => T;
>b15 : new <T>(x: { a: T; b: T; }) => T
>b15 : new <T>(x: { a: T; b: T;}) => T
>x : { a: T; b: T; }
>a : T
>b : T
Expand All @@ -240,7 +240,7 @@ module Errors {
>a15 : new (x: { a: string; b: number; }) => number

var b15a: new <T extends Base>(x: { a: T; b: T }) => number;
>b15a : new <T extends Base>(x: { a: T; b: T; }) => number
>b15a : new <T extends Base>(x: { a: T; b: T;}) => number
>x : { a: T; b: T; }
>a : T
>b : T
Expand Down
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