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

Author: Святослав Зайцев

src/services/goToDefinition.ts

@@ -32,6 +32,13 @@ namespace ts.GoToDefinition {
             return functionDeclaration ? [createDefinitionFromSignatureDeclaration(typeChecker, functionDeclaration)] : undefined;
         }
 
+        if ([SyntaxKind.CaseKeyword, SyntaxKind.DefaultKeyword].indexOf(node.kind) !== -1) {
+            const switchStatement = findAncestor(node.parent, n => n.kind === SyntaxKind.SwitchStatement) as SwitchStatement | undefined;
+            if (switchStatement) {
+                return [createDefinitionInfoFromSwitchStatement(switchStatement)];
+            }
+        }
+
         if (isStaticModifier(node) && isClassStaticBlockDeclaration(node.parent)) {
             const classDecl = node.parent.parent;
             const { symbol, failedAliasResolution } = getSymbol(classDecl, typeChecker, stopAtAlias);
@@ -510,4 +517,22 @@ namespace ts.GoToDefinition {
                 return false;
         }
     }
+
+    function createDefinitionInfoFromSwitchStatement(statement: SwitchStatement): DefinitionInfo {
+        const switchKeyword = find(statement.getChildren(), n => n.kind === SyntaxKind.SwitchKeyword);
+        const sourceFile = statement.getSourceFile();
+        return {
+            fileName: sourceFile.fileName,
+            textSpan: createTextSpanFromNode(switchKeyword!),
+            kind: ScriptElementKind.label,
+            name: 'switch',
+            containerKind: ScriptElementKind.unknown,
+            containerName: '',
+            contextSpan: createTextSpanFromNode(statement),
+            isLocal: false,
+            isAmbient: false,
+            unverified: false,
+            failedAliasResolution: undefined,
+        };
+    }
 }

tests/cases/fourslash/goToDefinitionSwitch1.ts

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

tests/cases/fourslash/goToDefinitionSwitch2.ts

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

tests/cases/fourslash/goToDefinitionSwitch3.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/goToDefinitionSwitch4.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/goToDefinitionSwitch5.ts

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

tests/cases/fourslash/goToDefinitionSwitch6.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", []);