Simplify isJumpStatementTarget and isLabelOfLabeledStatement users using type predicates (#22100)

Author: Andy

src/services/findAllReferences.ts

@@ -330,17 +330,15 @@ namespace ts.FindAllReferences.Core {
         }
 
         // Labels
-        if (isLabelName(node)) {
-            if (isJumpStatementTarget(node)) {
-                const labelDefinition = getTargetLabel((<BreakOrContinueStatement>node.parent), (<Identifier>node).text);
-                // if we have a label definition, look within its statement for references, if not, then
-                // the label is undefined and we have no results..
-                return labelDefinition && getLabelReferencesInNode(labelDefinition.parent, labelDefinition);
-            }
-            else {
-                // it is a label definition and not a target, search within the parent labeledStatement
-                return getLabelReferencesInNode(node.parent, <Identifier>node);
-            }
+        if (isJumpStatementTarget(node)) {
+            const labelDefinition = getTargetLabel(node.parent, node.text);
+            // if we have a label definition, look within its statement for references, if not, then
+            // the label is undefined and we have no results..
+            return labelDefinition && getLabelReferencesInNode(labelDefinition.parent, labelDefinition);
+        }
+        else if (isLabelOfLabeledStatement(node)) {
+            // it is a label definition and not a target, search within the parent labeledStatement
+            return getLabelReferencesInNode(node.parent, node);
         }
 
         if (isThis(node)) {

src/services/goToDefinition.ts

@@ -13,9 +13,8 @@ namespace ts.GoToDefinition {
 
         // Labels
         if (isJumpStatementTarget(node)) {
-            const labelName = (<Identifier>node).text;
-            const label = getTargetLabel((<BreakOrContinueStatement>node.parent), labelName);
-            return label ? [createDefinitionInfoFromName(label, ScriptElementKind.label, labelName, /*containerName*/ undefined)] : undefined;
+            const label = getTargetLabel(node.parent, node.text);
+            return label ? [createDefinitionInfoFromName(label, ScriptElementKind.label, node.text, /*containerName*/ undefined)] : undefined;
         }
 
         const typeChecker = program.getTypeChecker();

src/services/services.ts

@@ -1467,10 +1467,7 @@ namespace ts {
             const sourceFile = getValidSourceFile(fileName);
             const node = getTouchingPropertyName(sourceFile, position, /*includeJsDocComment*/ true);
             if (node === sourceFile) {
-                return undefined;
-            }
-
-            if (isLabelName(node)) {
+                // Avoid giving quickInfo for the sourceFile as a whole.
                 return undefined;
             }
 
@@ -1481,36 +1478,39 @@ namespace ts {
                 // Try getting just type at this position and show
                 switch (node.kind) {
                     case SyntaxKind.Identifier:
+                        if (isLabelName(node)) {
+                            // Type here will be 'any', avoid displaying this.
+                            return undefined;
+                        }
+                        // falls through
                     case SyntaxKind.PropertyAccessExpression:
                     case SyntaxKind.QualifiedName:
                     case SyntaxKind.ThisKeyword:
                     case SyntaxKind.ThisType:
                     case SyntaxKind.SuperKeyword:
                         // For the identifiers/this/super etc get the type at position
                         const type = typeChecker.getTypeAtLocation(node);
-                        if (type) {
-                            return {
-                                kind: ScriptElementKind.unknown,
-                                kindModifiers: ScriptElementKindModifier.none,
-                                textSpan: createTextSpan(node.getStart(), node.getWidth()),
-                                displayParts: typeToDisplayParts(typeChecker, type, getContainerNode(node)),
-                                documentation: type.symbol ? type.symbol.getDocumentationComment(typeChecker) : undefined,
-                                tags: type.symbol ? type.symbol.getJsDocTags() : undefined
-                            };
-                        }
+                        return type && {
+                            kind: ScriptElementKind.unknown,
+                            kindModifiers: ScriptElementKindModifier.none,
+                            textSpan: createTextSpanFromNode(node, sourceFile),
+                            displayParts: typeToDisplayParts(typeChecker, type, getContainerNode(node)),
+                            documentation: type.symbol ? type.symbol.getDocumentationComment(typeChecker) : undefined,
+                            tags: type.symbol ? type.symbol.getJsDocTags() : undefined
+                        };
                 }
 
                 return undefined;
             }
 
-            const displayPartsDocumentationsAndKind = SymbolDisplay.getSymbolDisplayPartsDocumentationAndSymbolKind(typeChecker, symbol, sourceFile, getContainerNode(node), node);
+            const { symbolKind, displayParts, documentation, tags } = SymbolDisplay.getSymbolDisplayPartsDocumentationAndSymbolKind(typeChecker, symbol, sourceFile, getContainerNode(node), node);
             return {
-                kind: displayPartsDocumentationsAndKind.symbolKind,
+                kind: symbolKind,
                 kindModifiers: SymbolDisplay.getSymbolModifiers(symbol),
-                textSpan: createTextSpan(node.getStart(), node.getWidth()),
-                displayParts: displayPartsDocumentationsAndKind.displayParts,
-                documentation: displayPartsDocumentationsAndKind.documentation,
-                tags: displayPartsDocumentationsAndKind.tags
+                textSpan: createTextSpanFromNode(node, sourceFile),
+                displayParts,
+                documentation,
+                tags,
             };
         }
 
@@ -1519,11 +1519,9 @@ namespace ts {
                 && isPropertyAssignment(node.parent)
                 && node.parent.name === node) {
                 const type = checker.getContextualType(node.parent.parent);
-                if (type) {
-                    const property = checker.getPropertyOfType(type, getTextOfIdentifierOrLiteral(node));
-                    if (property) {
-                        return property;
-                    }
+                const property = type && checker.getPropertyOfType(type, getTextOfIdentifierOrLiteral(node));
+                if (property) {
+                    return property;
                 }
             }
             return checker.getSymbolAtLocation(node);

src/services/utilities.ts

@@ -214,16 +214,12 @@ namespace ts {
         return undefined;
     }
 
-    export function isJumpStatementTarget(node: Node): boolean {
-        return node.kind === SyntaxKind.Identifier &&
-            (node.parent.kind === SyntaxKind.BreakStatement || node.parent.kind === SyntaxKind.ContinueStatement) &&
-            (<BreakOrContinueStatement>node.parent).label === node;
-    }
+    export function isJumpStatementTarget(node: Node): node is Identifier & { parent: BreakOrContinueStatement } {
+        return node.kind === SyntaxKind.Identifier && isBreakOrContinueStatement(node.parent) && node.parent.label === node;
+     }
 
-    function isLabelOfLabeledStatement(node: Node): boolean {
-        return node.kind === SyntaxKind.Identifier &&
-            node.parent.kind === SyntaxKind.LabeledStatement &&
-            (<LabeledStatement>node.parent).label === node;
+    export function isLabelOfLabeledStatement(node: Node): node is Identifier {
+        return node.kind === SyntaxKind.Identifier && isLabeledStatement(node.parent) && node.parent.label === node;
     }
 
     export function isLabelName(node: Node): boolean {