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Signature help turns off current-parameter display for non-trailing rest parameters #42592

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Merged
merged 7 commits into from
Feb 5, 2021
Merged

Signature help turns off current-parameter display for non-trailing rest parameters #42592

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1cf9a73
Signature help: support non-trailing rest parameters
sandersn Feb 1, 2021
e55212e
Change 'variadic' to 'rest'
sandersn Feb 1, 2021
692c590
fix missed rename
sandersn Feb 1, 2021
f0896f3
use single, original tuple instead
sandersn Feb 2, 2021
3351ccb
Revert "use single, original tuple instead"
sandersn Feb 4, 2021
2e32638
Improve sig help of trailing rest too
sandersn Feb 4, 2021
88e83d1
update API baselines
sandersn Feb 4, 2021
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23 changes: 17 additions & 6 deletions src/services/signatureHelp.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -517,7 +517,6 @@ namespace ts.SignatureHelp {
if (argumentIndex !== 0) {
Debug.assertLessThan(argumentIndex, argumentCount);
}

let selectedItemIndex = 0;
let itemsSeen = 0;
for (let i = 0; i < items.length; i++) {
Expand All @@ -541,8 +540,19 @@ namespace ts.SignatureHelp {
}

Debug.assert(selectedItemIndex !== -1); // If candidates is non-empty it should always include bestSignature. We check for an empty candidates before calling this function.

return { items: flatMapToMutable(items, identity), applicableSpan, selectedItemIndex, argumentIndex, argumentCount };
const help = { items: flatMapToMutable(items, identity), applicableSpan, selectedItemIndex, argumentIndex, argumentCount };
const selected = help.items[selectedItemIndex];
if (selected.isVariadic) {
const firstRest = findIndex(selected.parameters, p => !!p.isRest);
if (-1 < firstRest && firstRest < selected.parameters.length - 1) {
// We don't have any code to get this correct; instead, don't highlight a current parameter AT ALL
help.argumentIndex = selected.parameters.length;
Comment on lines +546 to +549
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We could also make this conditional upon argumentIndex >= firstRest if we wanted parameter highlighting to work up until the first rest, where the ambiguity begins. But maybe that would be a worse experience than consistently seeing no highlighting. I personally feel like parameter highlighting is pretty useful when parameters have JSDoc description, and it might be worthwhile to show them as often as we can. But it might be pretty confusing for it to stop working halfway through typing call arguments. Don’t have a super strong opinion here.

}
else {
help.argumentIndex = Math.min(help.argumentIndex, selected.parameters.length - 1);
}
}
return help;
}

function createTypeHelpItems(
Expand Down Expand Up @@ -638,15 +648,16 @@ namespace ts.SignatureHelp {
const param = checker.symbolToParameterDeclaration(parameter, enclosingDeclaration, signatureHelpNodeBuilderFlags)!;
printer.writeNode(EmitHint.Unspecified, param, sourceFile, writer);
});
const isOptional = checker.isOptionalParameter(<ParameterDeclaration>parameter.valueDeclaration);
return { name: parameter.name, documentation: parameter.getDocumentationComment(checker), displayParts, isOptional };
const isOptional = checker.isOptionalParameter(parameter.valueDeclaration as ParameterDeclaration);
const isRest = !!((parameter as TransientSymbol).checkFlags & CheckFlags.RestParameter);
return { name: parameter.name, documentation: parameter.getDocumentationComment(checker), displayParts, isOptional, isRest };
}

function createSignatureHelpParameterForTypeParameter(typeParameter: TypeParameter, checker: TypeChecker, enclosingDeclaration: Node, sourceFile: SourceFile, printer: Printer): SignatureHelpParameter {
const displayParts = mapToDisplayParts(writer => {
const param = checker.typeParameterToDeclaration(typeParameter, enclosingDeclaration, signatureHelpNodeBuilderFlags)!;
printer.writeNode(EmitHint.Unspecified, param, sourceFile, writer);
});
return { name: typeParameter.symbol.name, documentation: typeParameter.symbol.getDocumentationComment(checker), displayParts, isOptional: false };
return { name: typeParameter.symbol.name, documentation: typeParameter.symbol.getDocumentationComment(checker), displayParts, isOptional: false, isRest: false };
}
}
1 change: 1 addition & 0 deletions src/services/types.ts
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Expand Up @@ -1078,6 +1078,7 @@ namespace ts {
documentation: SymbolDisplayPart[];
displayParts: SymbolDisplayPart[];
isOptional: boolean;
isRest?: boolean;
}

export interface SelectionRange {
Expand Down
1 change: 1 addition & 0 deletions tests/baselines/reference/api/tsserverlibrary.d.ts
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Expand Up @@ -6027,6 +6027,7 @@ declare namespace ts {
documentation: SymbolDisplayPart[];
displayParts: SymbolDisplayPart[];
isOptional: boolean;
isRest?: boolean;
}
interface SelectionRange {
textSpan: TextSpan;
Expand Down
1 change: 1 addition & 0 deletions tests/baselines/reference/api/typescript.d.ts
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Expand Up @@ -6027,6 +6027,7 @@ declare namespace ts {
documentation: SymbolDisplayPart[];
displayParts: SymbolDisplayPart[];
isOptional: boolean;
isRest?: boolean;
}
interface SelectionRange {
textSpan: TextSpan;
Expand Down
32 changes: 32 additions & 0 deletions tests/cases/fourslash/signatureHelpLeadingRestTuple.ts
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@@ -0,0 +1,32 @@
/// <reference path='fourslash.ts' />

////export function leading(...args: [...names: string[], allCaps: boolean]): void {
////}
////
////leading(/*1*/);
////leading("ok", /*2*/);
////leading("ok", "ok", /*3*/);

verify.signatureHelp(
{
marker: "1",
text: "leading(...names: string[], allCaps: boolean): void",
overloadsCount: 1,
parameterCount: 2,
isVariadic: true,
},
{
marker: "2",
text: "leading(...names: string[], allCaps: boolean): void",
overloadsCount: 1,
parameterCount: 2,
isVariadic: true,
},
{
marker: "3",
text: "leading(...names: string[], allCaps: boolean): void",
overloadsCount: 1,
parameterCount: 2,
isVariadic: true,
},
);
38 changes: 38 additions & 0 deletions tests/cases/fourslash/signatureHelpTrailingRestTuple.ts
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@@ -0,0 +1,38 @@
/// <reference path='fourslash.ts' />

////export function leading(allCaps: boolean, ...names: string[]): void {
////}
////
////leading(/*1*/);
////leading(false, /*2*/);
////leading(false, "ok", /*3*/);

verify.signatureHelp(
{
marker: "1",
text: "leading(allCaps: boolean, ...names: string[]): void",
overloadsCount: 1,
parameterCount: 2,
parameterName: "allCaps",
parameterSpan: "allCaps: boolean",
isVariadic: true,
},
{
marker: "2",
text: "leading(allCaps: boolean, ...names: string[]): void",
overloadsCount: 1,
parameterCount: 2,
parameterName: "names",
parameterSpan: "...names: string[]",
isVariadic: true,
},
{
marker: "3",
text: "leading(allCaps: boolean, ...names: string[]): void",
overloadsCount: 1,
parameterCount: 2,
parameterName: "names",
parameterSpan: "...names: string[]",
isVariadic: true,
},
);