fix(51225): Go-to-definition on case or default should jump to the containing switch statement if available.

src/services/goToDefinition.ts

@@ -26,10 +26,22 @@ namespace ts.GoToDefinition {
             return label ? [createDefinitionInfoFromName(typeChecker, label, ScriptElementKind.label, node.text, /*containerName*/ undefined!)] : undefined; // TODO: GH#18217
         }
 
-        if (node.kind === SyntaxKind.ReturnKeyword) {
-            const functionDeclaration = findAncestor(node.parent, n =>
-                isClassStaticBlockDeclaration(n) ? "quit" : isFunctionLikeDeclaration(n)) as FunctionLikeDeclaration | undefined;
-            return functionDeclaration ? [createDefinitionFromSignatureDeclaration(typeChecker, functionDeclaration)] : undefined;
+        switch (node.kind) {
+            case SyntaxKind.ReturnKeyword:
+                const functionDeclaration = findAncestor(node.parent, n =>
+                  isClassStaticBlockDeclaration(n) ? "quit" : isFunctionLikeDeclaration(n)) as FunctionLikeDeclaration | undefined;
+                return functionDeclaration ? [createDefinitionFromSignatureDeclaration(typeChecker, functionDeclaration)] : undefined;
+            case SyntaxKind.DefaultKeyword:
+                if (!isDefaultClause(node.parent)) {
+                    break;
+                }
+                // falls through
+            case SyntaxKind.CaseKeyword:
+                const switchStatement = findAncestor(node.parent, isSwitchStatement);
+                if (switchStatement) {
+                    return [createDefinitionInfoFromStatement(switchStatement, SyntaxKind.SwitchKeyword, sourceFile, "switch")];
+                }
+                break;
         }
 
         if (isStaticModifier(node) && isClassStaticBlockDeclaration(node.parent)) {
@@ -510,4 +522,25 @@ namespace ts.GoToDefinition {
                 return false;
         }
     }
+
+    interface StatementWithExpression extends Statement {
+        readonly expression: Expression
+    }
+
+    function createDefinitionInfoFromStatement(statement: StatementWithExpression, keywordKind: KeywordSyntaxKind, sourceFile: SourceFile, name: string): DefinitionInfo {
+        const keyword = find(statement.getChildren(sourceFile), (node) => node.kind === keywordKind)!;
+        return {
+            fileName: sourceFile.fileName,
+            textSpan: createTextSpanFromNode(keyword, sourceFile),
+            kind: ScriptElementKind.keyword,
+            name,
+            containerKind: undefined!,
+            containerName: "",
+            contextSpan: createTextSpanFromNode(statement.expression, sourceFile),
+            isLocal: true,
+            isAmbient: false,
+            unverified: false,
+            failedAliasResolution: undefined,
+        };
+    }
 }

tests/cases/fourslash/goToDefinitionSwitchCase1.ts

@@ -0,0 +1,7 @@
+/// <reference path="fourslash.ts" />
+
+/////*end*/switch (null) {
+////  [|/*start*/case|] null: break;
+////}
+
+verify.goToDefinition("start", "end");

tests/cases/fourslash/goToDefinitionSwitchCase2.ts

@@ -0,0 +1,7 @@
+/// <reference path="fourslash.ts" />
+
+/////*end*/switch (null) {
+////  [|/*start*/default|]: break;
+////}
+
+verify.goToDefinition("start", "end");

tests/cases/fourslash/goToDefinitionSwitchCase3.ts

@@ -0,0 +1,12 @@
+/// <reference path="fourslash.ts" />
+
+/////*end1*/switch (null) {
+////  [|/*start1*/default|]: {
+////    /*end2*/switch (null) {
+////      [|/*start2*/default|]: break;
+////    }
+////  };
+////}
+
+verify.goToDefinition("start1", "end1");
+verify.goToDefinition("start2", "end2");

tests/cases/fourslash/goToDefinitionSwitchCase4.ts

@@ -0,0 +1,11 @@
+/// <reference path="fourslash.ts" />
+
+////      switch (null) {
+////          case null: break;
+////      }
+////
+////      /*end*/switch (null) {
+////         [|/*start*/case|] null: break;
+////      }
+
+verify.goToDefinition("start", "end");

tests/cases/fourslash/goToDefinitionSwitchCase5.ts

@@ -0,0 +1,5 @@
+/// <reference path="fourslash.ts" />
+
+/////*end*/export [|/*start*/default|] {}
+
+verify.goToDefinition("start", "end");

tests/cases/fourslash/goToDefinitionSwitchCase6.ts

@@ -0,0 +1,9 @@
+/// <reference path="fourslash.ts" />
+
+/////*d*/export default { [|/*a*/case|] };
+////[|/*b*/default|];
+////[|/*c*/case|] 42;
+
+verify.goToDefinition("a", "a");
+verify.goToDefinition("b", "d");
+verify.goToDefinition("c", []);

tests/cases/fourslash/goToDefinitionSwitchCase7.ts

@@ -0,0 +1,7 @@
+/// <reference path="fourslash.ts" />
+
+////switch (null) {
+////  case null:
+////    /*end*/export [|/*start*/default|] 123;
+
+verify.goToDefinition("start", "end");