fix(compiler): exponentiation should be right-to-left associative (#60101)

mmalerba · mmalerba · commit 4fe489f1b4f8 · 2025-02-28T16:28:10.000Z
For example, `a ** b ** c` should be equivalent to `a ** (b ** c)`, not `(a ** b) ** c` PR Close #60101
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/test/type_check_block_spec.ts b/packages/compiler-cli/src/ngtsc/typecheck/test/type_check_block_spec.ts
@@ -79,6 +79,7 @@ describe('type check blocks', () => {
     expect(tcb('{{a * b ** c + d}}')).toContain(
       '(((((this).a)) * ((((this).b)) ** (((this).c)))) + (((this).d)))',
     );
+    expect(tcb('{{a ** b ** c}}')).toContain('blah');
   });
 
   it('should handle attribute values for directive inputs', () => {
diff --git a/packages/compiler/src/expression_parser/parser.ts b/packages/compiler/src/expression_parser/parser.ts
@@ -960,7 +960,7 @@ class _ParseAST {
         );
       }
       this.advance();
-      const right = this.parsePrefix();
+      const right = this.parseExponentiation();
       result = new Binary(this.span(start), this.sourceSpan(start), '**', result, right);
     }
     return result;
diff --git a/packages/core/test/acceptance/integration_spec.ts b/packages/core/test/acceptance/integration_spec.ts
@@ -2787,6 +2787,16 @@ describe('acceptance integration tests', () => {
     expect(fixture.nativeElement.textContent).toEqual('1.03 | 0.97');
   });
 
+  it('should have right-to-left associativity for exponentiation', () => {
+    @Component({
+      template: '{{2 ** 2 ** 3}}',
+    })
+    class TestComponent {}
+    const fixture = TestBed.createComponent(TestComponent);
+    fixture.detectChanges();
+    expect(fixture.nativeElement.textContent).toEqual('256');
+  });
+
   describe('tView.firstUpdatePass', () => {
     function isFirstUpdatePass() {
       const lView = getLView();

Original file line number	Diff line number	Diff line change
`@@ -960,7 +960,7 @@ class _ParseAST {`
`960`	`960`	`);`
`961`	`961`	`}`
`962`	`962`	`this.advance();`
`963`		`- const right = this.parsePrefix();`
	`963`	`+ const right = this.parseExponentiation();`
`964`	`964`	`result = new Binary(this.span(start), this.sourceSpan(start), '**', result, right);`
`965`	`965`	`}`
`966`	`966`	`return result;`