refactor(compiler-cli): find symbol for output when there is a two way binding (#40185)

This commit fixes the Template Type Checker's `getSymbolOfNode` so that
it is able to retrieve a symbol for the `BoundEvent` of a two-way
binding. Previously, the implementation would locate the node in the TCB
for the input because it appeared first and shares the same `keySpan` as
the event binding. To fix this, the TCB node search now verifies that
the located node matches the expected name for the output subscription:
either `addEventListener` for a native listener  or the class member of the Angular `@Output`
in the case of an Angular output, as would be the case for two-way
bindings.

PR Close #40185

packages/compiler-cli/src/ngtsc/typecheck/src/template_symbol_builder.ts

@@ -168,24 +168,49 @@ export class SymbolBuilder {
   }
 
   private getSymbolOfBoundEvent(eventBinding: TmplAstBoundEvent): OutputBindingSymbol|null {
+    const consumer = this.templateData.boundTarget.getConsumerOfBinding(eventBinding);
+    if (consumer === null) {
+      return null;
+    }
+
     // Outputs in the TCB look like one of the two:
     // * _outputHelper(_t1["outputField"]).subscribe(handler);
     // * _t1.addEventListener(handler);
     // Even with strict null checks disabled, we still produce the access as a separate statement
     // so that it can be found here.
-    const outputFieldAccesses = findAllMatchingNodes(
-        this.typeCheckBlock, {withSpan: eventBinding.keySpan, filter: isAccessExpression});
+    let expectedAccess: string;
+    if (consumer instanceof TmplAstTemplate || consumer instanceof TmplAstElement) {
+      expectedAccess = 'addEventListener';
+    } else {
+      const bindingPropertyNames = consumer.outputs.getByBindingPropertyName(eventBinding.name);
+      if (bindingPropertyNames === null || bindingPropertyNames.length === 0) {
+        return null;
+      }
+      // Note that we only get the expectedAccess text from a single consumer of the binding. If
+      // there are multiple consumers (not supported in the `boundTarget` API) and one of them has
+      // an alias, it will not get matched here.
+      expectedAccess = bindingPropertyNames[0].classPropertyName;
+    }
+
+    function filter(n: ts.Node): n is ts.PropertyAccessExpression|ts.ElementAccessExpression {
+      if (!isAccessExpression(n)) {
+        return false;
+      }
+
+      if (ts.isPropertyAccessExpression(n)) {
+        return n.name.getText() === expectedAccess;
+      } else {
+        return ts.isStringLiteral(n.argumentExpression) &&
+            n.argumentExpression.text === expectedAccess;
+      }
+    }
+    const outputFieldAccesses =
+        findAllMatchingNodes(this.typeCheckBlock, {withSpan: eventBinding.keySpan, filter});
 
     const bindings: BindingSymbol[] = [];
     for (const outputFieldAccess of outputFieldAccesses) {
-      const consumer = this.templateData.boundTarget.getConsumerOfBinding(eventBinding);
-      if (consumer === null) {
-        continue;
-      }
-
       if (consumer instanceof TmplAstTemplate || consumer instanceof TmplAstElement) {
-        if (!ts.isPropertyAccessExpression(outputFieldAccess) ||
-            outputFieldAccess.name.text !== 'addEventListener') {
+        if (!ts.isPropertyAccessExpression(outputFieldAccess)) {
           continue;
         }
 
@@ -233,10 +258,10 @@ export class SymbolBuilder {
         });
       }
     }
+
     if (bindings.length === 0) {
       return null;
     }
-
     return {kind: SymbolKind.Output, bindings};
   }
 

packages/compiler-cli/src/ngtsc/typecheck/test/type_checker__get_symbol_of_template_node_spec.ts

@@ -1348,6 +1348,55 @@ runInEachFileSystem(() => {
                    .parent.name?.text)
             .toEqual('TestDir');
       });
+
+
+      it('returns output symbol for two way binding', () => {
+        const fileName = absoluteFrom('/main.ts');
+        const dirFile = absoluteFrom('/dir.ts');
+        const {program, templateTypeChecker} = setup([
+          {
+            fileName,
+            templates: {'Cmp': `<div dir [(ngModel)]="value"></div>`},
+            source: `
+                export class Cmp {
+                  value = '';
+                }`,
+            declarations: [
+              {
+                name: 'TestDir',
+                selector: '[dir]',
+                file: dirFile,
+                type: 'directive',
+                inputs: {ngModel: 'ngModel'},
+                outputs: {ngModelChange: 'ngModelChange'},
+              },
+            ]
+          },
+          {
+            fileName: dirFile,
+            source: `
+                export class TestDir {
+                  ngModel!: string;
+                  ngModelChange!: EventEmitter<string>;
+                }`,
+            templates: {},
+          }
+        ]);
+        const sf = getSourceFileOrError(program, fileName);
+        const cmp = getClass(sf, 'Cmp');
+
+        const nodes = templateTypeChecker.getTemplate(cmp)!;
+
+        const outputABinding = (nodes[0] as TmplAstElement).outputs[0];
+        const symbol = templateTypeChecker.getSymbolOfNode(outputABinding, cmp)!;
+        assertOutputBindingSymbol(symbol);
+        expect(
+            (symbol.bindings[0].tsSymbol!.declarations[0] as ts.PropertyDeclaration).name.getText())
+            .toEqual('ngModelChange');
+        expect((symbol.bindings[0].tsSymbol!.declarations[0] as ts.PropertyDeclaration)
+                   .parent.name?.text)
+            .toEqual('TestDir');
+      });
     });
 
     describe('for elements', () => {