feat(ivy): let ngtsc statically evaluate `Array.concat` calls (#29887)

Previously, only static evaluation of `Array.slice` was implemented in
ngtsc's static evaluator. This commit adds support for `Array.concat`.

Closes #29835

PR Close #29887

packages/compiler-cli/src/ngtsc/partial_evaluator/src/builtin.ts

@@ -22,3 +22,21 @@ export class ArraySliceBuiltinFn extends BuiltinFn {
     }
   }
 }
+
+export class ArrayConcatBuiltinFn extends BuiltinFn {
+  constructor(private node: ts.Node, private lhs: ResolvedValueArray) { super(); }
+
+  evaluate(args: ResolvedValueArray): ResolvedValue {
+    const result: ResolvedValueArray = [...this.lhs];
+    for (const arg of args) {
+      if (arg instanceof DynamicValue) {
+        result.push(DynamicValue.fromDynamicInput(this.node, arg));
+      } else if (Array.isArray(arg)) {
+        result.push(...arg);
+      } else {
+        result.push(arg);
+      }
+    }
+    return result;
+  }
+}

packages/compiler-cli/src/ngtsc/partial_evaluator/src/interpreter.ts

@@ -12,7 +12,7 @@ import {Reference} from '../../imports';
 import {OwningModule} from '../../imports/src/references';
 import {Declaration, ReflectionHost} from '../../reflection';
 
-import {ArraySliceBuiltinFn} from './builtin';
+import {ArrayConcatBuiltinFn, ArraySliceBuiltinFn} from './builtin';
 import {DynamicValue} from './dynamic';
 import {ForeignFunctionResolver, VisitedFilesCallback} from './interface';
 import {BuiltinFn, EnumValue, ResolvedValue, ResolvedValueArray, ResolvedValueMap} from './result';
@@ -340,6 +340,8 @@ export class StaticInterpreter {
         return lhs.length;
       } else if (rhs === 'slice') {
         return new ArraySliceBuiltinFn(node, lhs);
+      } else if (rhs === 'concat') {
+        return new ArrayConcatBuiltinFn(node, lhs);
       }
       if (typeof rhs !== 'number' || !Number.isInteger(rhs)) {
         return DynamicValue.fromUnknown(node);

packages/compiler-cli/src/ngtsc/partial_evaluator/test/evaluator_spec.ts

@@ -130,6 +130,14 @@ describe('ngtsc metadata', () => {
     expect(evaluate(`const a = [1, 2, 3];`, 'a[\'slice\']()')).toEqual([1, 2, 3]);
   });
 
+  it('array `concat` function works', () => {
+    expect(evaluate(`const a = [1, 2], b = [3, 4];`, 'a[\'concat\'](b)')).toEqual([1, 2, 3, 4]);
+    expect(evaluate(`const a = [1, 2], b = 3;`, 'a[\'concat\'](b)')).toEqual([1, 2, 3]);
+    expect(evaluate(`const a = [1, 2], b = 3, c = [4, 5];`, 'a[\'concat\'](b, c)')).toEqual([
+      1, 2, 3, 4, 5
+    ]);
+  });
+
   it('negation works', () => {
     expect(evaluate(`const x = 3;`, '!x')).toEqual(false);
     expect(evaluate(`const x = 3;`, '!!x')).toEqual(true);