feat(compiler): support unary operators for more accurate type checking (#37918)

Prior to this change, the unary + and - operators would be parsed as `x - 0`
and `0 - x` respectively. The runtime semantics of these expressions are
equivalent, however they may introduce inaccurate template type checking
errors as the literal type is lost, for example:

```ts
@Component({
  template: `<button [disabled]="isAdjacent(-1)"></button>`
})
export class Example {
  isAdjacent(direction: -1 | 1): boolean { return false; }
}
```

would incorrectly report a type-check error:

> error TS2345: Argument of type 'number' is not assignable to parameter
  of type '-1 | 1'.

Additionally, the translated expression for the unary + operator would be
considered as arithmetic expression with an incompatible left-hand side:

> error TS2362: The left-hand side of an arithmetic operation must be of
  type 'any', 'number', 'bigint' or an enum type.

To resolve this issues, the implicit transformation should be avoided.
This commit adds a new unary AST node to represent these expressions,
allowing for more accurate type-checking.

Fixes #20845
Fixes #36178

PR Close #37918

packages/compiler/test/expression_parser/parser_spec.ts

@@ -34,11 +34,11 @@ describe('parser', () => {
       checkAction('undefined');
     });
 
-    it('should parse unary - expressions', () => {
-      checkAction('-1', '0 - 1');
-      checkAction('+1', '1 - 0');
-      checkAction(`-'1'`, `0 - "1"`);
-      checkAction(`+'1'`, `"1" - 0`);
+    it('should parse unary - and + expressions', () => {
+      checkAction('-1', '-1');
+      checkAction('+1', '+1');
+      checkAction(`-'1'`, `-"1"`);
+      checkAction(`+'1'`, `+"1"`);
     });
 
     it('should parse unary ! expressions', () => {

packages/compiler/test/expression_parser/utils/unparser.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {AbsoluteSourceSpan, AST, AstVisitor, ASTWithSource, Binary, BindingPipe, Chain, Conditional, FunctionCall, ImplicitReceiver, Interpolation, KeyedRead, KeyedWrite, LiteralArray, LiteralMap, LiteralPrimitive, MethodCall, NonNullAssert, ParseSpan, PrefixNot, PropertyRead, PropertyWrite, Quote, RecursiveAstVisitor, SafeMethodCall, SafePropertyRead} from '../../../src/expression_parser/ast';
+import {AST, AstVisitor, ASTWithSource, Binary, BindingPipe, Chain, Conditional, FunctionCall, ImplicitReceiver, Interpolation, KeyedRead, KeyedWrite, LiteralArray, LiteralMap, LiteralPrimitive, MethodCall, NonNullAssert, ParseSpan, PrefixNot, PropertyRead, PropertyWrite, Quote, RecursiveAstVisitor, SafeMethodCall, SafePropertyRead, Unary} from '../../../src/expression_parser/ast';
 import {DEFAULT_INTERPOLATION_CONFIG, InterpolationConfig} from '../../../src/ml_parser/interpolation_config';
 
 class Unparser implements AstVisitor {
@@ -35,6 +35,11 @@ class Unparser implements AstVisitor {
     this._visit(ast.value);
   }
 
+  visitUnary(ast: Unary, context: any) {
+    this._expression += ast.operator;
+    this._visit(ast.expr);
+  }
+
   visitBinary(ast: Binary, context: any) {
     this._visit(ast.left);
     this._expression += ` ${ast.operation} `;

packages/compiler/test/expression_parser/utils/validator.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {AST, Binary, BindingPipe, Chain, Conditional, FunctionCall, ImplicitReceiver, Interpolation, KeyedRead, KeyedWrite, LiteralArray, LiteralMap, LiteralPrimitive, MethodCall, ParseSpan, PrefixNot, PropertyRead, PropertyWrite, Quote, RecursiveAstVisitor, SafeMethodCall, SafePropertyRead} from '../../../src/expression_parser/ast';
+import {AST, Binary, BindingPipe, Chain, Conditional, FunctionCall, ImplicitReceiver, Interpolation, KeyedRead, KeyedWrite, LiteralArray, LiteralMap, LiteralPrimitive, MethodCall, ParseSpan, PrefixNot, PropertyRead, PropertyWrite, Quote, RecursiveAstVisitor, SafeMethodCall, SafePropertyRead, Unary} from '../../../src/expression_parser/ast';
 
 import {unparse} from './unparser';
 
@@ -34,6 +34,10 @@ class ASTValidator extends RecursiveAstVisitor {
     this.parentSpan = oldParent;
   }
 
+  visitUnary(ast: Unary, context: any): any {
+    this.validate(ast, () => super.visitUnary(ast, context));
+  }
+
   visitBinary(ast: Binary, context: any): any {
     this.validate(ast, () => super.visitBinary(ast, context));
   }