Support new() built-in for type params.

nevkontakte · nevkontakte · commit cc4773e5a668 · 2023-11-12T17:57:54.000Z
For the most part it already worked through the $newDataPointer(), I
only had to update it to handle pointers to array, which are a wrapped
type.
diff --git a/compiler/prelude/types.js b/compiler/prelude/types.js
@@ -855,7 +855,7 @@ var $ptrType = elem => {
 };
 
 var $newDataPointer = (data, constructor) => {
-    if (constructor.elem.kind === $kindStruct) {
+    if (constructor.elem.kind === $kindStruct || constructor.elem.kind === $kindArray) {
         return data;
     }
     return new constructor(() => { return data; }, v => { data = v; });
diff --git a/tests/typeparams/builtins_test.go b/tests/typeparams/builtins_test.go
@@ -2,6 +2,7 @@ package typeparams_test
 
 import (
 	"fmt"
+	"reflect"
 	"testing"
 )
 
@@ -163,3 +164,37 @@ func TestCap(t *testing.T) {
 		})
 	}
 }
+
+func _new[T any]() *T {
+	return new(T)
+}
+
+func TestNew(t *testing.T) {
+	type S struct{ i int }
+
+	tests := []struct {
+		desc string
+		got  any
+		want any
+	}{{
+		desc: "struct S",
+		got:  *_new[S](),
+		want: S{},
+	}, {
+		desc: "[3]int",
+		got:  *_new[[3]int](),
+		want: [3]int{},
+	}, {
+		desc: "int",
+		got:  *_new[int](),
+		want: int(0),
+	}}
+
+	for _, test := range tests {
+		t.Run(test.desc, func(t *testing.T) {
+			if !reflect.DeepEqual(test.got, test.want) {
+				t.Errorf("Got: new(%T) = %#v. Want: %#v.", test.want, test.got, test.want)
+			}
+		})
+	}
+}

Original file line number	Diff line number	Diff line change
`@@ -855,7 +855,7 @@ var $ptrType = elem => {`
`855`	`855`	`};`
`856`	`856`
`857`	`857`	`var $newDataPointer = (data, constructor) => {`
`858`		`- if (constructor.elem.kind === $kindStruct) {`
	`858`	`+ if (constructor.elem.kind === $kindStruct \|\| constructor.elem.kind === $kindArray) {`
`859`	`859`	`return data;`
`860`	`860`	`}`
`861`	`861`	`return new constructor(() => { return data; }, v => { data = v; });`