Include source node inferences in string literal completions

src/compiler/checker.ts

@@ -469,6 +469,7 @@ import {
     isCallChain,
     isCallExpression,
     isCallLikeExpression,
+    isCallLikeOrFunctionLikeExpression,
     isCallOrNewExpression,
     isCallSignatureDeclaration,
     isCatchClause,
@@ -1653,12 +1654,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         getTypeOfPropertyOfContextualType,
         getFullyQualifiedName,
         getResolvedSignature: (node, candidatesOutArray, argumentCount) => getResolvedSignatureWorker(node, candidatesOutArray, argumentCount, CheckMode.Normal),
-        getResolvedSignatureForStringLiteralCompletions: (call, editingArgument, candidatesOutArray, checkMode = CheckMode.IsForStringLiteralArgumentCompletions) => {
-            if (checkMode & CheckMode.IsForStringLiteralArgumentCompletions) {
-                return runWithInferenceBlockedFromSourceNode(editingArgument, () => getResolvedSignatureWorker(call, candidatesOutArray, /*argumentCount*/ undefined, checkMode & ~CheckMode.IsForStringLiteralArgumentCompletions));
-            }
-            return runWithoutResolvedSignatureCaching(editingArgument, () => getResolvedSignatureWorker(call, candidatesOutArray, /*argumentCount*/ undefined, checkMode & ~CheckMode.IsForStringLiteralArgumentCompletions));
-        },
+        getCandidateSignaturesForStringLiteralCompletions,
         getResolvedSignatureForSignatureHelp: (node, candidatesOutArray, argumentCount) => runWithoutResolvedSignatureCaching(node, () => getResolvedSignatureWorker(node, candidatesOutArray, argumentCount, CheckMode.IsForSignatureHelp)),
         getExpandedParameters,
         hasEffectiveRestParameter,
@@ -1838,32 +1834,55 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         typeHasCallOrConstructSignatures,
     };
 
+    function getCandidateSignaturesForStringLiteralCompletions(call: CallLikeExpression, editingArgument: Node) {
+        const candidatesSet = new Set<Signature>();
+        const candidates: Signature[] = [];
+
+        // first, get candidates when inference is blocked from the source node.
+        runWithInferenceBlockedFromSourceNode(editingArgument, () => getResolvedSignatureWorker(call, candidates, /*argumentCount*/ undefined, CheckMode.IsForStringLiteralArgumentCompletions));
+        for (const candidate of candidates) {
+            candidatesSet.add(candidate);
+        }
+
+        // reset candidates for second pass
+        candidates.length = 0;
+
+        // next, get candidates where the source node is considered for inference.
+        runWithoutResolvedSignatureCaching(editingArgument, () => getResolvedSignatureWorker(call, candidates, /*argumentCount*/ undefined, CheckMode.Normal));
+        for (const candidate of candidates) {
+            candidatesSet.add(candidate);
+        }
+
+        return arrayFrom(candidatesSet);
+    }
+
     function runWithoutResolvedSignatureCaching<T>(node: Node | undefined, fn: () => T): T {
-        const cachedResolvedSignatures = [];
-        const cachedTypes = [];
-        while (node) {
-            if (isCallLikeExpression(node) || isFunctionLike(node)) {
+        node = findAncestor(node, isCallLikeOrFunctionLikeExpression);
+        if (node) {
+            const cachedResolvedSignatures = [];
+            const cachedTypes = [];
+            while (node) {
                 const nodeLinks = getNodeLinks(node);
-                const resolvedSignature = nodeLinks.resolvedSignature;
-                cachedResolvedSignatures.push([nodeLinks, resolvedSignature] as const);
+                cachedResolvedSignatures.push([nodeLinks, nodeLinks.resolvedSignature] as const);
                 nodeLinks.resolvedSignature = undefined;
+                if (isFunctionLike(node)) {
+                    const symbolLinks = getSymbolLinks(getSymbolOfDeclaration(node));
+                    const type = symbolLinks.type;
+                    cachedTypes.push([symbolLinks, type] as const);
+                    symbolLinks.type = undefined;
+                }
+                node = findAncestor(node.parent, isCallLikeOrFunctionLikeExpression);
             }
-            if (isFunctionLike(node)) {
-                const symbolLinks = getSymbolLinks(getSymbolOfDeclaration(node));
-                const type = symbolLinks.type;
-                cachedTypes.push([symbolLinks, type] as const);
-                symbolLinks.type = undefined;
+            const result = fn();
+            for (const [nodeLinks, resolvedSignature] of cachedResolvedSignatures) {
+                nodeLinks.resolvedSignature = resolvedSignature;
             }
-            node = node.parent;
-        }
-        const result = fn();
-        for (const [nodeLinks, resolvedSignature] of cachedResolvedSignatures) {
-            nodeLinks.resolvedSignature = resolvedSignature;
-        }
-        for (const [symbolLinks, type] of cachedTypes) {
-            symbolLinks.type = type;
+            for (const [symbolLinks, type] of cachedTypes) {
+                symbolLinks.type = type;
+            }
+            return result;
         }
-        return result;
+        return fn();
     }
 
     function runWithInferenceBlockedFromSourceNode<T>(node: Node | undefined, fn: () => T): T {
@@ -33207,7 +33226,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
 
         for (let i = 0; i < argCount; i++) {
             const arg = args[i];
-            if (arg.kind !== SyntaxKind.OmittedExpression) {
+            if (arg.kind !== SyntaxKind.OmittedExpression && !(checkMode & CheckMode.IsForStringLiteralArgumentCompletions && hasSkipDirectInferenceFlag(arg))) {
                 const paramType = getTypeAtPosition(signature, i);
                 if (couldContainTypeVariables(paramType)) {
                     const argType = checkExpressionWithContextualType(arg, paramType, context, checkMode);
@@ -33849,6 +33868,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         // decorators are applied to a declaration by the emitter, and not to an expression.
         const isSingleNonGenericCandidate = candidates.length === 1 && !candidates[0].typeParameters;
         let argCheckMode = !isDecorator && !isSingleNonGenericCandidate && some(args, isContextSensitive) ? CheckMode.SkipContextSensitive : CheckMode.Normal;
+        argCheckMode |= checkMode & CheckMode.IsForStringLiteralArgumentCompletions;
 
         // The following variables are captured and modified by calls to chooseOverload.
         // If overload resolution or type argument inference fails, we want to report the

src/compiler/types.ts

@@ -1,6 +1,5 @@
 import {
     BaseNodeFactory,
-    CheckMode,
     CreateSourceFileOptions,
     EmitHelperFactory,
     GetCanonicalFileName,
@@ -5010,7 +5009,7 @@ export interface TypeChecker {
      */
     getResolvedSignature(node: CallLikeExpression, candidatesOutArray?: Signature[], argumentCount?: number): Signature | undefined;
     /** @internal */ getResolvedSignatureForSignatureHelp(node: CallLikeExpression, candidatesOutArray?: Signature[], argumentCount?: number): Signature | undefined;
-    /** @internal */ getResolvedSignatureForStringLiteralCompletions(call: CallLikeExpression, editingArgument: Node, candidatesOutArray: Signature[], checkMode?: CheckMode): Signature | undefined;
+    /** @internal */ getCandidateSignaturesForStringLiteralCompletions(call: CallLikeExpression, editingArgument: Node): Signature[];
     /** @internal */ getExpandedParameters(sig: Signature): readonly (readonly Symbol[])[];
     /** @internal */ hasEffectiveRestParameter(sig: Signature): boolean;
     /** @internal */ containsArgumentsReference(declaration: SignatureDeclaration): boolean;

src/compiler/utilitiesPublic.ts

@@ -1920,6 +1920,11 @@ export function isPropertyAccessOrQualifiedName(node: Node): node is PropertyAcc
         || kind === SyntaxKind.QualifiedName;
 }
 
+/** @internal */
+export function isCallLikeOrFunctionLikeExpression(node: Node): node is CallLikeExpression | SignatureDeclaration {
+    return isCallLikeExpression(node) || isFunctionLike(node);
+}
+
 export function isCallLikeExpression(node: Node): node is CallLikeExpression {
     switch (node.kind) {
         case SyntaxKind.JsxOpeningElement:

src/services/stringCompletions.ts

@@ -7,7 +7,6 @@ import {
     CaseClause,
     changeExtension,
     CharacterCodes,
-    CheckMode,
     combinePaths,
     comparePaths,
     comparePatternKeys,
@@ -119,7 +118,6 @@ import {
     ScriptElementKind,
     ScriptElementKindModifier,
     ScriptTarget,
-    Signature,
     signatureHasRestParameter,
     SignatureHelp,
     singleElementArray,
@@ -414,7 +412,7 @@ function getStringLiteralCompletionEntries(sourceFile: SourceFile, node: StringL
                 // Get string literal completions from specialized signatures of the target
                 // i.e. declare function f(a: 'A');
                 // f("/*completion position*/")
-                return argumentInfo && (getStringLiteralCompletionsFromSignature(argumentInfo.invocation, node, argumentInfo, typeChecker) || getStringLiteralCompletionsFromSignature(argumentInfo.invocation, node, argumentInfo, typeChecker, CheckMode.Normal)) || fromContextualType(ContextFlags.None);
+                return argumentInfo && getStringLiteralCompletionsFromSignature(argumentInfo.invocation, node, argumentInfo, typeChecker) || fromContextualType(ContextFlags.None);
             }
             // falls through (is `require("")` or `require(""` or `import("")`)
 
@@ -504,12 +502,11 @@ function getAlreadyUsedTypesInStringLiteralUnion(union: UnionTypeNode, current:
     return mapDefined(union.types, type => type !== current && isLiteralTypeNode(type) && isStringLiteral(type.literal) ? type.literal.text : undefined);
 }
 
-function getStringLiteralCompletionsFromSignature(call: CallLikeExpression, arg: StringLiteralLike, argumentInfo: SignatureHelp.ArgumentInfoForCompletions, checker: TypeChecker, checkMode = CheckMode.IsForStringLiteralArgumentCompletions): StringLiteralCompletionsFromTypes | undefined {
+function getStringLiteralCompletionsFromSignature(call: CallLikeExpression, arg: StringLiteralLike, argumentInfo: SignatureHelp.ArgumentInfoForCompletions, checker: TypeChecker): StringLiteralCompletionsFromTypes | undefined {
     let isNewIdentifier = false;
     const uniques = new Map<string, true>();
-    const candidates: Signature[] = [];
     const editingArgument = isJsxOpeningLikeElement(call) ? Debug.checkDefined(findAncestor(arg.parent, isJsxAttribute)) : arg;
-    checker.getResolvedSignatureForStringLiteralCompletions(call, editingArgument, candidates, checkMode);
+    const candidates = checker.getCandidateSignaturesForStringLiteralCompletions(call, editingArgument);
     const types = flatMap(candidates, candidate => {
         if (!signatureHasRestParameter(candidate) && argumentInfo.argumentCount > candidate.parameters.length) return;
         let type = candidate.getTypeParameterAtPosition(argumentInfo.argumentIndex);

tests/cases/fourslash/stringLiteralCompletionsForGenericConditionalTypesUsingTemplateLiteralTypes.ts

@@ -0,0 +1,14 @@
+/// <reference path="fourslash.ts" />
+
+// repro from https://github.com/microsoft/TypeScript/issues/49680
+
+//// type PathOf<T, K extends string, P extends string = ""> =
+////   K extends `${infer U}.${infer V}`
+////     ? U extends keyof T ? PathOf<T[U], V, `${P}${U}.`> : `${P}${keyof T & (string | number)}`
+////     : K extends keyof T ? `${P}${K}` : `${P}${keyof T & (string | number)}`;
+////
+//// declare function consumer<K extends string>(path: PathOf<{a: string, b: {c: string}}, K>) : number;
+////
+//// consumer('b./*ts*/')
+
+verify.completions({ marker: ["ts"], exact: ["a", "b", "b.c"] });

tests/cases/fourslash/stringLiteralCompletionsInPositionTypedUsingRest.ts

@@ -0,0 +1,21 @@
+/// <reference path="fourslash.ts" />
+
+// repro from https://github.com/microsoft/TypeScript/issues/49680#issuecomment-1249191842
+
+//// declare function pick<T extends object, K extends keyof T>(obj: T, ...keys: K[]): Pick<T, K>;
+//// declare function pick2<T extends object, K extends (keyof T)[]>(obj: T, ...keys: K): Pick<T, K[number]>;
+////
+//// const obj = { aaa: 1, bbb: '2', ccc: true };
+////
+//// pick(obj, 'aaa', '/*ts1*/');
+//// pick2(obj, 'aaa', '/*ts2*/');
+
+// repro from https://github.com/microsoft/TypeScript/issues/49680#issuecomment-1273677941
+
+//// class Q<T> {
+////   public select<Keys extends keyof T>(...args: Keys[]) {}
+//// }
+//// new Q<{ id: string; name: string }>().select("name", "/*ts3*/");
+
+verify.completions({ marker: ["ts1", "ts2"], exact: ["aaa", "bbb", "ccc"] });
+verify.completions({ marker: ["ts3"], exact: ["name", "id"] });