refactor(language-service): Add quick info for built in control flow/blocks (angular#52386)

Adds hover info for:

* Defer blocks
* Triggers and trigger behavior keywords
* For loop empty block
* Track keyword in for loop block

resolves angular/vscode-ng-language-service#1946

PR Close angular#52386

Author: atscott

packages/compiler/src/render3/r3_ast.ts

@@ -118,16 +118,22 @@ export class Element implements Node {
 }
 
 export abstract class DeferredTrigger implements Node {
-  constructor(public sourceSpan: ParseSourceSpan) {}
+  constructor(
+      public nameSpan: ParseSourceSpan|null, public sourceSpan: ParseSourceSpan,
+      public prefetchSpan: ParseSourceSpan|null, public whenOrOnSourceSpan: ParseSourceSpan|null) {}
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitDeferredTrigger(this);
   }
 }
 
 export class BoundDeferredTrigger extends DeferredTrigger {
-  constructor(public value: AST, sourceSpan: ParseSourceSpan) {
-    super(sourceSpan);
+  constructor(
+      public value: AST, sourceSpan: ParseSourceSpan, prefetchSpan: ParseSourceSpan|null,
+      whenSourceSpan: ParseSourceSpan) {
+    // BoundDeferredTrigger is for 'when' triggers. These aren't really "triggers" and don't have a
+    // nameSpan. Trigger names are the built in event triggers like hover, interaction, etc.
+    super(/** nameSpan */ null, sourceSpan, prefetchSpan, whenSourceSpan);
   }
 }
 
@@ -136,54 +142,75 @@ export class IdleDeferredTrigger extends DeferredTrigger {}
 export class ImmediateDeferredTrigger extends DeferredTrigger {}
 
 export class HoverDeferredTrigger extends DeferredTrigger {
-  constructor(public reference: string|null, sourceSpan: ParseSourceSpan) {
-    super(sourceSpan);
+  constructor(
+      public reference: string|null, nameSpan: ParseSourceSpan, sourceSpan: ParseSourceSpan,
+      prefetchSpan: ParseSourceSpan|null, onSourceSpan: ParseSourceSpan|null) {
+    super(nameSpan, sourceSpan, prefetchSpan, onSourceSpan);
   }
 }
 
 export class TimerDeferredTrigger extends DeferredTrigger {
-  constructor(public delay: number, sourceSpan: ParseSourceSpan) {
-    super(sourceSpan);
+  constructor(
+      public delay: number, nameSpan: ParseSourceSpan, sourceSpan: ParseSourceSpan,
+      prefetchSpan: ParseSourceSpan|null, onSourceSpan: ParseSourceSpan|null) {
+    super(nameSpan, sourceSpan, prefetchSpan, onSourceSpan);
   }
 }
 
 export class InteractionDeferredTrigger extends DeferredTrigger {
-  constructor(public reference: string|null, sourceSpan: ParseSourceSpan) {
-    super(sourceSpan);
+  constructor(
+      public reference: string|null, nameSpan: ParseSourceSpan, sourceSpan: ParseSourceSpan,
+      prefetchSpan: ParseSourceSpan|null, onSourceSpan: ParseSourceSpan|null) {
+    super(nameSpan, sourceSpan, prefetchSpan, onSourceSpan);
   }
 }
 
 export class ViewportDeferredTrigger extends DeferredTrigger {
-  constructor(public reference: string|null, sourceSpan: ParseSourceSpan) {
-    super(sourceSpan);
+  constructor(
+      public reference: string|null, nameSpan: ParseSourceSpan, sourceSpan: ParseSourceSpan,
+      prefetchSpan: ParseSourceSpan|null, onSourceSpan: ParseSourceSpan|null) {
+    super(nameSpan, sourceSpan, prefetchSpan, onSourceSpan);
   }
 }
 
-export class DeferredBlockPlaceholder implements Node {
+export class BlockNode {
   constructor(
-      public children: Node[], public minimumTime: number|null, public sourceSpan: ParseSourceSpan,
+      public nameSpan: ParseSourceSpan, public sourceSpan: ParseSourceSpan,
       public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {}
+}
+
+export class DeferredBlockPlaceholder extends BlockNode implements Node {
+  constructor(
+      public children: Node[], public minimumTime: number|null, nameSpan: ParseSourceSpan,
+      sourceSpan: ParseSourceSpan, startSourceSpan: ParseSourceSpan,
+      endSourceSpan: ParseSourceSpan|null) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitDeferredBlockPlaceholder(this);
   }
 }
 
-export class DeferredBlockLoading implements Node {
+export class DeferredBlockLoading extends BlockNode implements Node {
   constructor(
       public children: Node[], public afterTime: number|null, public minimumTime: number|null,
-      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan,
-      public endSourceSpan: ParseSourceSpan|null) {}
+      nameSpan: ParseSourceSpan, sourceSpan: ParseSourceSpan, startSourceSpan: ParseSourceSpan,
+      endSourceSpan: ParseSourceSpan|null) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitDeferredBlockLoading(this);
   }
 }
 
-export class DeferredBlockError implements Node {
+export class DeferredBlockError extends BlockNode implements Node {
   constructor(
-      public children: Node[], public sourceSpan: ParseSourceSpan,
-      public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {}
+      public children: Node[], nameSpan: ParseSourceSpan, sourceSpan: ParseSourceSpan,
+      startSourceSpan: ParseSourceSpan, endSourceSpan: ParseSourceSpan|null) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitDeferredBlockError(this);
@@ -200,7 +227,7 @@ export interface DeferredBlockTriggers {
   viewport?: ViewportDeferredTrigger;
 }
 
-export class DeferredBlock implements Node {
+export class DeferredBlock extends BlockNode implements Node {
   readonly triggers: Readonly<DeferredBlockTriggers>;
   readonly prefetchTriggers: Readonly<DeferredBlockTriggers>;
   private readonly definedTriggers: (keyof DeferredBlockTriggers)[];
@@ -210,8 +237,9 @@ export class DeferredBlock implements Node {
       public children: Node[], triggers: DeferredBlockTriggers,
       prefetchTriggers: DeferredBlockTriggers, public placeholder: DeferredBlockPlaceholder|null,
       public loading: DeferredBlockLoading|null, public error: DeferredBlockError|null,
-      public sourceSpan: ParseSourceSpan, public mainBlockSpan: ParseSourceSpan,
-      public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {
+      nameSpan: ParseSourceSpan, sourceSpan: ParseSourceSpan, public mainBlockSpan: ParseSourceSpan,
+      startSourceSpan: ParseSourceSpan, endSourceSpan: ParseSourceSpan|null) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
     this.triggers = triggers;
     this.prefetchTriggers = prefetchTriggers;
     // We cache the keys since we know that they won't change and we
@@ -239,25 +267,31 @@ export class DeferredBlock implements Node {
   }
 }
 
-export class SwitchBlock implements Node {
+export class SwitchBlock extends BlockNode implements Node {
   constructor(
       public expression: AST, public cases: SwitchBlockCase[],
       /**
        * These blocks are only captured to allow for autocompletion in the language service. They
        * aren't meant to be processed in any other way.
        */
-      public unknownBlocks: UnknownBlock[], public sourceSpan: ParseSourceSpan,
-      public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {}
+      public unknownBlocks: UnknownBlock[], sourceSpan: ParseSourceSpan,
+      startSourceSpan: ParseSourceSpan, endSourceSpan: ParseSourceSpan|null,
+      nameSpan: ParseSourceSpan) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitSwitchBlock(this);
   }
 }
 
-export class SwitchBlockCase implements Node {
+export class SwitchBlockCase extends BlockNode implements Node {
   constructor(
-      public expression: AST|null, public children: Node[], public sourceSpan: ParseSourceSpan,
-      public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {}
+      public expression: AST|null, public children: Node[], sourceSpan: ParseSourceSpan,
+      startSourceSpan: ParseSourceSpan, endSourceSpan: ParseSourceSpan|null,
+      nameSpan: ParseSourceSpan) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitSwitchBlockCase(this);
@@ -270,44 +304,53 @@ export class SwitchBlockCase implements Node {
 export type ForLoopBlockContext =
     Record<'$index'|'$first'|'$last'|'$even'|'$odd'|'$count', Variable>;
 
-export class ForLoopBlock implements Node {
+export class ForLoopBlock extends BlockNode implements Node {
   constructor(
       public item: Variable, public expression: ASTWithSource, public trackBy: ASTWithSource,
-      public contextVariables: ForLoopBlockContext, public children: Node[],
-      public empty: ForLoopBlockEmpty|null, public sourceSpan: ParseSourceSpan,
-      public mainBlockSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan,
-      public endSourceSpan: ParseSourceSpan|null) {}
+      public trackKeywordSpan: ParseSourceSpan, public contextVariables: ForLoopBlockContext,
+      public children: Node[], public empty: ForLoopBlockEmpty|null, sourceSpan: ParseSourceSpan,
+      public mainBlockSpan: ParseSourceSpan, startSourceSpan: ParseSourceSpan,
+      endSourceSpan: ParseSourceSpan|null, nameSpan: ParseSourceSpan) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitForLoopBlock(this);
   }
 }
 
-export class ForLoopBlockEmpty implements Node {
+export class ForLoopBlockEmpty extends BlockNode implements Node {
   constructor(
-      public children: Node[], public sourceSpan: ParseSourceSpan,
-      public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {}
+      public children: Node[], sourceSpan: ParseSourceSpan, startSourceSpan: ParseSourceSpan,
+      endSourceSpan: ParseSourceSpan|null, nameSpan: ParseSourceSpan) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitForLoopBlockEmpty(this);
   }
 }
 
-export class IfBlock implements Node {
+export class IfBlock extends BlockNode implements Node {
   constructor(
-      public branches: IfBlockBranch[], public sourceSpan: ParseSourceSpan,
-      public startSourceSpan: ParseSourceSpan, public endSourceSpan: ParseSourceSpan|null) {}
+      public branches: IfBlockBranch[], sourceSpan: ParseSourceSpan,
+      startSourceSpan: ParseSourceSpan, endSourceSpan: ParseSourceSpan|null,
+      nameSpan: ParseSourceSpan) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitIfBlock(this);
   }
 }
 
-export class IfBlockBranch implements Node {
+export class IfBlockBranch extends BlockNode implements Node {
   constructor(
       public expression: AST|null, public children: Node[], public expressionAlias: Variable|null,
-      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan,
-      public endSourceSpan: ParseSourceSpan|null) {}
+      sourceSpan: ParseSourceSpan, startSourceSpan: ParseSourceSpan,
+      endSourceSpan: ParseSourceSpan|null, nameSpan: ParseSourceSpan) {
+    super(nameSpan, sourceSpan, startSourceSpan, endSourceSpan);
+  }
 
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitIfBlockBranch(this);

packages/compiler/src/render3/r3_control_flow.ts

@@ -59,7 +59,8 @@ export function createIfBlock(
   if (mainBlockParams !== null) {
     branches.push(new t.IfBlockBranch(
         mainBlockParams.expression, html.visitAll(visitor, ast.children, ast.children),
-        mainBlockParams.expressionAlias, ast.sourceSpan, ast.startSourceSpan, ast.endSourceSpan));
+        mainBlockParams.expressionAlias, ast.sourceSpan, ast.startSourceSpan, ast.endSourceSpan,
+        ast.nameSpan));
   }
 
   for (const block of connectedBlocks) {
@@ -70,12 +71,13 @@ export function createIfBlock(
         const children = html.visitAll(visitor, block.children, block.children);
         branches.push(new t.IfBlockBranch(
             params.expression, children, params.expressionAlias, block.sourceSpan,
-            block.startSourceSpan, block.endSourceSpan));
+            block.startSourceSpan, block.endSourceSpan, block.nameSpan));
       }
     } else if (block.name === 'else') {
       const children = html.visitAll(visitor, block.children, block.children);
       branches.push(new t.IfBlockBranch(
-          null, children, null, block.sourceSpan, block.startSourceSpan, block.endSourceSpan));
+          null, children, null, block.sourceSpan, block.startSourceSpan, block.endSourceSpan,
+          block.nameSpan));
     }
   }
 
@@ -92,7 +94,8 @@ export function createIfBlock(
   }
 
   return {
-    node: new t.IfBlock(branches, wholeSourceSpan, ast.startSourceSpan, ifBlockEndSourceSpan),
+    node: new t.IfBlock(
+        branches, wholeSourceSpan, ast.startSourceSpan, ifBlockEndSourceSpan, ast.nameSpan),
     errors,
   };
 }
@@ -115,7 +118,7 @@ export function createForLoop(
       } else {
         empty = new t.ForLoopBlockEmpty(
             html.visitAll(visitor, block.children, block.children), block.sourceSpan,
-            block.startSourceSpan, block.endSourceSpan);
+            block.startSourceSpan, block.endSourceSpan, block.nameSpan);
       }
     } else {
       errors.push(new ParseError(block.sourceSpan, `Unrecognized @for loop block "${block.name}"`));
@@ -135,9 +138,9 @@ export function createForLoop(
       const sourceSpan =
           new ParseSourceSpan(ast.sourceSpan.start, endSpan?.end ?? ast.sourceSpan.end);
       node = new t.ForLoopBlock(
-          params.itemName, params.expression, params.trackBy, params.context,
-          html.visitAll(visitor, ast.children, ast.children), empty, sourceSpan, ast.sourceSpan,
-          ast.startSourceSpan, endSpan);
+          params.itemName, params.expression, params.trackBy.expression, params.trackBy.keywordSpan,
+          params.context, html.visitAll(visitor, ast.children, ast.children), empty, sourceSpan,
+          ast.sourceSpan, ast.startSourceSpan, endSpan, ast.nameSpan);
     }
   }
 
@@ -172,7 +175,7 @@ export function createSwitchBlock(
         null;
     const ast = new t.SwitchBlockCase(
         expression, html.visitAll(visitor, node.children, node.children), node.sourceSpan,
-        node.startSourceSpan, node.endSourceSpan);
+        node.startSourceSpan, node.endSourceSpan, node.nameSpan);
 
     if (expression === null) {
       defaultCase = ast;
@@ -189,7 +192,7 @@ export function createSwitchBlock(
   return {
     node: new t.SwitchBlock(
         primaryExpression, cases, unknownBlocks, ast.sourceSpan, ast.startSourceSpan,
-        ast.endSourceSpan),
+        ast.endSourceSpan, ast.nameSpan),
     errors
   };
 }
@@ -217,7 +220,7 @@ function parseForLoopParameters(
   const result = {
     itemName: new t.Variable(
         itemName, '$implicit', expressionParam.sourceSpan, expressionParam.sourceSpan),
-    trackBy: null as ASTWithSource | null,
+    trackBy: null as {expression: ASTWithSource, keywordSpan: ParseSourceSpan} | null,
     expression: parseBlockParameterToBinding(expressionParam, bindingParser, rawExpression),
     context: {} as t.ForLoopBlockContext,
   };
@@ -237,7 +240,10 @@ function parseForLoopParameters(
         errors.push(
             new ParseError(param.sourceSpan, '@for loop can only have one "track" expression'));
       } else {
-        result.trackBy = parseBlockParameterToBinding(param, bindingParser, trackMatch[1]);
+        const expression = parseBlockParameterToBinding(param, bindingParser, trackMatch[1]);
+        const keywordSpan = new ParseSourceSpan(
+            param.sourceSpan.start, param.sourceSpan.start.moveBy('track'.length));
+        result.trackBy = {expression, keywordSpan};
       }
       continue;
     }

packages/compiler/src/render3/r3_deferred_blocks.ts

@@ -48,8 +48,7 @@ export function createDeferredBlock(
   const {triggers, prefetchTriggers} =
       parsePrimaryTriggers(ast.parameters, bindingParser, errors, placeholder);
 
-  // The `defer` block has a main span encompassing all of the connected branches as well. For the
-  // span of only the first "main" branch, use `mainSourceSpan`.
+  // The `defer` block has a main span encompassing all of the connected branches as well.
   let lastEndSourceSpan = ast.endSourceSpan;
   let endOfLastSourceSpan = ast.sourceSpan.end;
   if (connectedBlocks.length > 0) {
@@ -58,12 +57,13 @@ export function createDeferredBlock(
     endOfLastSourceSpan = lastConnectedBlock.sourceSpan.end;
   }
 
-  const mainDeferredSourceSpan = new ParseSourceSpan(ast.sourceSpan.start, endOfLastSourceSpan);
+  const sourceSpanWithConnectedBlocks =
+      new ParseSourceSpan(ast.sourceSpan.start, endOfLastSourceSpan);
 
   const node = new t.DeferredBlock(
       html.visitAll(visitor, ast.children, ast.children), triggers, prefetchTriggers, placeholder,
-      loading, error, mainDeferredSourceSpan, ast.sourceSpan, ast.startSourceSpan,
-      lastEndSourceSpan);
+      loading, error, ast.nameSpan, sourceSpanWithConnectedBlocks, ast.sourceSpan,
+      ast.startSourceSpan, lastEndSourceSpan);
 
   return {node, errors};
 }
@@ -140,7 +140,7 @@ function parsePlaceholderBlock(ast: html.Block, visitor: html.Visitor): t.Deferr
   }
 
   return new t.DeferredBlockPlaceholder(
-      html.visitAll(visitor, ast.children, ast.children), minimumTime, ast.sourceSpan,
+      html.visitAll(visitor, ast.children, ast.children), minimumTime, ast.nameSpan, ast.sourceSpan,
       ast.startSourceSpan, ast.endSourceSpan);
 }
 
@@ -181,8 +181,8 @@ function parseLoadingBlock(ast: html.Block, visitor: html.Visitor): t.DeferredBl
   }
 
   return new t.DeferredBlockLoading(
-      html.visitAll(visitor, ast.children, ast.children), afterTime, minimumTime, ast.sourceSpan,
-      ast.startSourceSpan, ast.endSourceSpan);
+      html.visitAll(visitor, ast.children, ast.children), afterTime, minimumTime, ast.nameSpan,
+      ast.sourceSpan, ast.startSourceSpan, ast.endSourceSpan);
 }
 
 
@@ -192,8 +192,8 @@ function parseErrorBlock(ast: html.Block, visitor: html.Visitor): t.DeferredBloc
   }
 
   return new t.DeferredBlockError(
-      html.visitAll(visitor, ast.children, ast.children), ast.sourceSpan, ast.startSourceSpan,
-      ast.endSourceSpan);
+      html.visitAll(visitor, ast.children, ast.children), ast.nameSpan, ast.sourceSpan,
+      ast.startSourceSpan, ast.endSourceSpan);
 }
 
 function parsePrimaryTriggers(