Restore index signature details in property hovers

tsc/internal/checker/exports.go

@@ -1,6 +1,9 @@
 package checker
 
 import (
+	"maps"
+	"slices"
+
 	"github.com/microsoft/TypeScript/tsc/internal/ast"
 	"github.com/microsoft/TypeScript/tsc/internal/diagnostics"
 )
@@ -347,6 +350,14 @@ func (c *Checker) GetIndexInfosOfType(t *Type) []*IndexInfo {
 	return c.getIndexInfosOfType(t)
 }
 
+func (c *Checker) GetIndexInfosOfIndexSymbol(symbol *ast.Symbol) []*IndexInfo {
+	var siblingSymbols []*ast.Symbol
+	if symbol.Parent != nil {
+		siblingSymbols = slices.Collect(maps.Values(c.getMembersOfSymbol(symbol.Parent)))
+	}
+	return c.getIndexInfosOfIndexSymbol(symbol, siblingSymbols)
+}
+
 func (c *Checker) IsContextSensitive(node *ast.Node) bool {
 	return c.isContextSensitive(node)
 }

tsc/internal/fourslash/tests/jsDocPropertyDescription1_test.go

@@ -8,7 +8,6 @@ import (
 )
 
 func TestJsDocPropertyDescription1(t *testing.T) {
-	t.Skip("Known failing fourslash test")
 	t.Parallel()
 	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
 	const content = `interface StringExample {

tsc/internal/fourslash/tests/jsDocPropertyDescription4_test.go

@@ -8,7 +8,6 @@ import (
 )
 
 func TestJsDocPropertyDescription4(t *testing.T) {
-	t.Skip("Known failing fourslash test")
 	t.Parallel()
 	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
 	const content = `interface MultipleExample {

tsc/internal/fourslash/tests/jsDocPropertyDescription7_test.go

@@ -8,7 +8,6 @@ import (
 )
 
 func TestJsDocPropertyDescription7(t *testing.T) {
-	t.Skip("Known failing fourslash test")
 	t.Parallel()
 	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
 	const content = `class StringClass {

tsc/internal/fourslash/tests/quickInfoIndexSignatureOwnerAlias_test.go

@@ -0,0 +1,26 @@
+package fourslash_test
+
+import (
+	"testing"
+
+	"github.com/microsoft/TypeScript/tsc/internal/fourslash"
+	"github.com/microsoft/TypeScript/tsc/internal/testutil"
+)
+
+func TestQuickInfoIndexSignatureOwnerAlias(t *testing.T) {
+	t.Parallel()
+	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
+	const content = `
+namespace Outer {
+    export namespace Inner {
+        export interface Dictionary { [k: string]: number; }
+    }
+}
+import Alias = Outer.Inner;
+declare const dictionary: Alias.Dictionary;
+dictionary./*alias*/aliasKey;
+`
+	f, done := fourslash.NewFourslash(t, nil /*capabilities*/, content)
+	defer done()
+	f.VerifyQuickInfoAt(t, "alias", "(index) Dictionary[string]: number", "")
+}

tsc/internal/fourslash/tests/quickInfoIndexSignatureOwnerNamespace_test.go

@@ -0,0 +1,34 @@
+package fourslash_test
+
+import (
+	"testing"
+
+	"github.com/microsoft/TypeScript/tsc/internal/fourslash"
+	"github.com/microsoft/TypeScript/tsc/internal/testutil"
+)
+
+func TestQuickInfoIndexSignatureOwnerNamespace(t *testing.T) {
+	t.Parallel()
+	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
+	const content = `
+namespace Outer {
+    export namespace Inner {
+        export interface Dictionary { [k: string]: number; }
+        declare const inside: Dictionary;
+        inside./*inside*/insideKey;
+    }
+}
+namespace Other {
+    export interface Dictionary { [k: string]: number; }
+}
+declare const outside: Outer.Inner.Dictionary;
+outside./*outside*/outsideKey;
+declare const other: Other.Dictionary;
+other./*other*/otherKey;
+`
+	f, done := fourslash.NewFourslash(t, nil /*capabilities*/, content)
+	defer done()
+	f.VerifyQuickInfoAt(t, "inside", "(index) Dictionary[string]: number", "")
+	f.VerifyQuickInfoAt(t, "outside", "(index) Dictionary[string]: number", "")
+	f.VerifyQuickInfoAt(t, "other", "(index) Dictionary[string]: number", "")
+}

tsc/internal/fourslash/tests/quickInfoIndexSignaturePropertyUnchecked_test.go

@@ -0,0 +1,32 @@
+package fourslash_test
+
+import (
+	"testing"
+
+	"github.com/microsoft/TypeScript/tsc/internal/fourslash"
+	"github.com/microsoft/TypeScript/tsc/internal/testutil"
+)
+
+func TestQuickInfoIndexSignaturePropertyUnchecked(t *testing.T) {
+	t.Parallel()
+	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
+	const content = `
+// @strict: true
+// @noUncheckedIndexedAccess: true
+interface Dictionary {
+    /** The stored value. */
+    [k: string]: number;
+}
+declare const dictionary: Dictionary;
+dictionary./*read*/a;
+dictionary./*write*/a = 1;
+if (dictionary.a !== undefined) {
+    dictionary./*narrowed*/a;
+}
+`
+	f, done := fourslash.NewFourslash(t, nil /*capabilities*/, content)
+	defer done()
+	f.VerifyQuickInfoAt(t, "read", "(index) Dictionary[string]: number | undefined", "The stored value.")
+	f.VerifyQuickInfoAt(t, "write", "(index) Dictionary[string]: number", "The stored value.")
+	f.VerifyQuickInfoAt(t, "narrowed", "(index) Dictionary[string]: number", "The stored value.")
+}

tsc/internal/fourslash/tests/quickInfoIndexSignatureProperty_test.go

@@ -0,0 +1,41 @@
+package fourslash_test
+
+import (
+	"testing"
+
+	"github.com/microsoft/TypeScript/tsc/internal/fourslash"
+	"github.com/microsoft/TypeScript/tsc/internal/testutil"
+)
+
+func TestQuickInfoIndexSignatureProperty(t *testing.T) {
+	t.Parallel()
+	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
+	// Regression test for https://github.com/microsoft/TypeScript/issues/64582.
+	const content = `
+// @strict: true
+declare const x: { [k: string]: number };
+x./*anonymous*/a;
+interface Dictionary<T> {
+    [k: string]: T;
+}
+
+declare const dictionary: Dictionary<number>;
+dictionary./*generic*/a;
+interface Multiple {
+    [k: string | symbol]: number;
+}
+declare const multiple: Multiple;
+multiple./*multiple*/a;
+interface Pattern {
+    [k: ` + "`data_${string}`" + `]: number;
+}
+declare const pattern: Pattern;
+pattern./*pattern*/data_example;
+`
+	f, done := fourslash.NewFourslash(t, nil /*capabilities*/, content)
+	defer done()
+	f.VerifyQuickInfoAt(t, "anonymous", "(index) x[string]: number", "")
+	f.VerifyQuickInfoAt(t, "generic", "(index) Dictionary[string]: number", "")
+	f.VerifyQuickInfoAt(t, "multiple", "(index) Multiple[string | symbol]: number", "")
+	f.VerifyQuickInfoAt(t, "pattern", "(index) Pattern[`data_${string}`]: number", "")
+}

tsc/internal/fourslash/tests/quickInfoOnPropDeclaredUsingIndexSignatureOnInterfaceWithBase_test.go

@@ -8,7 +8,6 @@ import (
 )
 
 func TestQuickInfoOnPropDeclaredUsingIndexSignatureOnInterfaceWithBase(t *testing.T) {
-	t.Skip("Known failing fourslash test")
 	t.Parallel()
 	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
 	const content = `interface P {}

tsc/internal/ls/hover.go

@@ -683,7 +683,22 @@ func getQuickInfoAndDeclarationAtLocation(c *checker.Checker, symbol *ast.Symbol
 		}
 		if flags&(ast.SymbolFlagsVariable|ast.SymbolFlagsProperty|ast.SymbolFlagsAccessor) != 0 {
 			writeNewLine()
-			if symbol.CheckFlags&ast.CheckFlagsIndexSymbol == 0 {
+			if symbol.CheckFlags&ast.CheckFlagsIndexSymbol != 0 {
+				dpw.WritePunctuation("(")
+				dpw.Write("index")
+				dpw.WritePunctuation(") ")
+				if symbol.Parent != nil {
+					writeSymbolClassified(symbol.Parent, nil, ast.SymbolFlagsNone, symbolFormatFlags)
+				}
+				dpw.WritePunctuation("[")
+				for i, info := range c.GetIndexInfosOfIndexSymbol(symbol) {
+					if i != 0 {
+						dpw.WritePunctuation(" | ")
+					}
+					writeTypeClassified(info.KeyType(), container, typeFormatFlags)
+				}
+				dpw.WritePunctuation("]: ")
+			} else {
 				switch {
 				case flags&ast.SymbolFlagsProperty != 0:
 					dpw.WritePunctuation("(")

tsc/testdata/baselines/reference/fourslash/quickInfo/quickInfoOnJsxIntrinsicDeclaredUsingCatchCallIndexSignature.baseline

@@ -7,7 +7,7 @@
 //  ^^^
 // | ----------------------------------------------------------------------
 // | ```typescript
-// | any
+// | (index) IntrinsicElements[string]: any
 // | ```
 // | 
 // | ----------------------------------------------------------------------
@@ -25,7 +25,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```typescript\nany\n```\n"
+        "value": "```typescript\n(index) IntrinsicElements[string]: any\n```\n"
       },
       "range": {
         "start": {

tsc/testdata/baselines/reference/fourslash/quickInfo/quickInfoOnJsxIntrinsicDeclaredUsingTemplateLiteralTypeSignatures.baseline

@@ -10,15 +10,15 @@
 //  ^^^^^^
 // | ----------------------------------------------------------------------
 // | ```typescript
-// | any
+// | (index) IntrinsicElements[`foo${string}`]: any
 // | ```
 // | 
 // | ----------------------------------------------------------------------
 // <foobarbaz />;
 //  ^^^^^^^^^
 // | ----------------------------------------------------------------------
 // | ```typescript
-// | any
+// | (index) IntrinsicElements[`foo${string}` | `foobar${string}`]: any
 // | ```
 // | 
 // | ----------------------------------------------------------------------
@@ -36,7 +36,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```typescript\nany\n```\n"
+        "value": "```typescript\n(index) IntrinsicElements[`foo${string}`]: any\n```\n"
       },
       "range": {
         "start": {
@@ -63,7 +63,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```typescript\nany\n```\n"
+        "value": "```typescript\n(index) IntrinsicElements[`foo${string}` | `foobar${string}`]: any\n```\n"
       },
       "range": {
         "start": {