From ff8868e8d151b30d10783cd7b6f3af63a187429e Mon Sep 17 00:00:00 2001
From: Joe Savona <joesavona@fb.com>
Date: Fri, 17 Mar 2023 16:18:11 -0700
Subject: [PATCH] Fix self-closing jsx element codegen

We were never emitting self-closing jsx elements because children were never
null, we now set children to null if they were empty in the AST.
---
 compiler/forget/src/HIR/BuildHIR.ts                           | 2 +-
 .../forget/src/__tests__/fixtures/compiler/call.expect.md     | 2 +-
 .../fixtures/compiler/capture-func-passed-to-jsx.expect.md    | 2 +-
 .../compiler/capturing-function-member-expr-call.expect.md    | 2 +-
 .../__tests__/fixtures/compiler/concise-arrow-expr.expect.md  | 2 +-
 .../fixtures/compiler/conditional-on-mutable.expect.md        | 4 ++--
 .../src/__tests__/fixtures/compiler/constructor.expect.md     | 2 +-
 .../__tests__/fixtures/compiler/controlled-input.expect.md    | 2 +-
 .../escape-analysis-destructured-rest-element.expect.md       | 2 +-
 .../fixtures/compiler/independent-across-if.expect.md         | 2 +-
 .../src/__tests__/fixtures/compiler/independent.expect.md     | 2 +-
 .../fixtures/compiler/interdependent-across-if.expect.md      | 2 +-
 .../src/__tests__/fixtures/compiler/interdependent.expect.md  | 2 +-
 .../fixtures/compiler/jsx-member-expression.expect.md         | 2 +-
 .../src/__tests__/fixtures/compiler/jsx-spread.expect.md      | 2 +-
 .../__tests__/fixtures/compiler/property-assignment.expect.md | 2 +-
 .../fixtures/compiler/reassignment-conditional.expect.md      | 2 +-
 .../src/__tests__/fixtures/compiler/reassignment.expect.md    | 2 +-
 .../src/__tests__/fixtures/compiler/ssa-call-jsx-2.expect.md  | 2 +-
 .../src/__tests__/fixtures/compiler/ssa-call-jsx.expect.md    | 2 +-
 .../fixtures/compiler/switch-non-final-default.expect.md      | 2 +-
 .../forget/src/__tests__/fixtures/compiler/switch.expect.md   | 2 +-
 .../__tests__/fixtures/compiler/use-callback-simple.expect.md | 2 +-
 .../src/__tests__/fixtures/compiler/useMemo-simple.expect.md  | 2 +-
 .../fixtures/disableMemoizeJsxElements/Component.expect.md    | 2 +-
 25 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/compiler/forget/src/HIR/BuildHIR.ts b/compiler/forget/src/HIR/BuildHIR.ts
index d67b6846bf..ce418cf400 100644
--- a/compiler/forget/src/HIR/BuildHIR.ts
+++ b/compiler/forget/src/HIR/BuildHIR.ts
@@ -1439,7 +1439,7 @@ function lowerExpression(
         kind: "JsxExpression",
         tag,
         props,
-        children,
+        children: children.length === 0 ? null : children,
         loc: exprLoc,
       };
     }
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/call.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/call.expect.md
index 7af3132878..d13e956b5c 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/call.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/call.expect.md
@@ -38,7 +38,7 @@ function Component(props) {
   }
   let t0;
   if ($[2] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = <div a={a} b={b}></div>;
+    t0 = <div a={a} b={b} />;
     $[2] = t0;
   } else {
     t0 = $[2];
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/capture-func-passed-to-jsx.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/capture-func-passed-to-jsx.expect.md
index acae2e4956..7d1ac8cade 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/capture-func-passed-to-jsx.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/capture-func-passed-to-jsx.expect.md
@@ -59,7 +59,7 @@ function component(a, b) {
   const c_7 = $[7] !== x;
   let t3;
   if (c_7) {
-    t3 = <Foo x={x}></Foo>;
+    t3 = <Foo x={x} />;
     $[7] = x;
     $[8] = t3;
   } else {
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/capturing-function-member-expr-call.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/capturing-function-member-expr-call.expect.md
index 2dc57b8057..183ad33557 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/capturing-function-member-expr-call.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/capturing-function-member-expr-call.expect.md
@@ -50,7 +50,7 @@ function component(t27) {
   const c_5 = $[5] !== hide;
   let t2;
   if (c_4 || c_5) {
-    t2 = <Foo poke={poke} hide={hide}></Foo>;
+    t2 = <Foo poke={poke} hide={hide} />;
     $[4] = poke;
     $[5] = hide;
     $[6] = t2;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/concise-arrow-expr.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/concise-arrow-expr.expect.md
index 517503efd5..82a51fb6b0 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/concise-arrow-expr.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/concise-arrow-expr.expect.md
@@ -29,7 +29,7 @@ function component() {
   const c_2 = $[2] !== handler;
   let t1;
   if (c_2) {
-    t1 = <Foo handler={handler}></Foo>;
+    t1 = <Foo handler={handler} />;
     $[2] = handler;
     $[3] = t1;
   } else {
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/conditional-on-mutable.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/conditional-on-mutable.expect.md
index f80aacf62e..fb8c6fbed0 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/conditional-on-mutable.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/conditional-on-mutable.expect.md
@@ -59,7 +59,7 @@ function ComponentA(props) {
   const c_4 = $[4] !== b;
   let t0;
   if (c_3 || c_4) {
-    t0 = <Foo a={a} b={b}></Foo>;
+    t0 = <Foo a={a} b={b} />;
     $[3] = a;
     $[4] = b;
     $[5] = t0;
@@ -94,7 +94,7 @@ function ComponentB(props) {
   const c_4 = $[4] !== b;
   let t0;
   if (c_3 || c_4) {
-    t0 = <Foo a={a} b={b}></Foo>;
+    t0 = <Foo a={a} b={b} />;
     $[3] = a;
     $[4] = b;
     $[5] = t0;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/constructor.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/constructor.expect.md
index 08b57f01d8..03806a533e 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/constructor.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/constructor.expect.md
@@ -37,7 +37,7 @@ function Component(props) {
   }
   let t0;
   if ($[2] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = <div a={a} b={b}></div>;
+    t0 = <div a={a} b={b} />;
     $[2] = t0;
   } else {
     t0 = $[2];
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/controlled-input.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/controlled-input.expect.md
index 417dcef789..cf714af29b 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/controlled-input.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/controlled-input.expect.md
@@ -30,7 +30,7 @@ function component() {
   const c_3 = $[3] !== x;
   let t1;
   if (c_2 || c_3) {
-    t1 = <input onChange={handler} value={x}></input>;
+    t1 = <input onChange={handler} value={x} />;
     $[2] = handler;
     $[3] = x;
     $[4] = t1;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/escape-analysis-destructured-rest-element.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/escape-analysis-destructured-rest-element.expect.md
index 14682a35a5..955cf03386 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/escape-analysis-destructured-rest-element.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/escape-analysis-destructured-rest-element.expect.md
@@ -39,7 +39,7 @@ function Component(props) {
   const c_5 = $[5] !== d;
   let t0;
   if (c_4 || c_5) {
-    t0 = <div b={b} d={d}></div>;
+    t0 = <div b={b} d={d} />;
     $[4] = b;
     $[5] = d;
     $[6] = t0;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/independent-across-if.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/independent-across-if.expect.md
index 34633c17d8..755e324210 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/independent-across-if.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/independent-across-if.expect.md
@@ -82,7 +82,7 @@ function Component(props) {
   const c_6 = $[6] !== b;
   let t0;
   if (c_5 || c_6) {
-    t0 = <Foo a={a} b={b}></Foo>;
+    t0 = <Foo a={a} b={b} />;
     $[5] = a;
     $[6] = b;
     $[7] = t0;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/independent.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/independent.expect.md
index 9a344bd0d9..1f0e15b143 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/independent.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/independent.expect.md
@@ -63,7 +63,7 @@ function Component(props) {
   const c_5 = $[5] !== b;
   let t2;
   if (c_4 || c_5) {
-    t2 = <Foo a={a} b={b}></Foo>;
+    t2 = <Foo a={a} b={b} />;
     $[4] = a;
     $[5] = b;
     $[6] = t2;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/interdependent-across-if.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/interdependent-across-if.expect.md
index 0d0f6cab93..f54421b400 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/interdependent-across-if.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/interdependent-across-if.expect.md
@@ -70,7 +70,7 @@ function Component(props) {
   const c_6 = $[6] !== b;
   let t0;
   if (c_5 || c_6) {
-    t0 = <Foo a={a} b={b}></Foo>;
+    t0 = <Foo a={a} b={b} />;
     $[5] = a;
     $[6] = b;
     $[7] = t0;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/interdependent.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/interdependent.expect.md
index 9c7bc4c7c3..445e5bc6dc 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/interdependent.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/interdependent.expect.md
@@ -58,7 +58,7 @@ function Component(props) {
   const c_5 = $[5] !== b;
   let t0;
   if (c_4 || c_5) {
-    t0 = <Foo a={a} b={b}></Foo>;
+    t0 = <Foo a={a} b={b} />;
     $[4] = a;
     $[5] = b;
     $[6] = t0;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/jsx-member-expression.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/jsx-member-expression.expect.md
index 899564d65e..215cf59dd1 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/jsx-member-expression.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/jsx-member-expression.expect.md
@@ -19,7 +19,7 @@ function Component(props) {
   const $ = React.unstable_useMemoCache(2);
   let t0;
   if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = <Foo.Bar.Baz></Foo.Bar.Baz>;
+    t0 = <Foo.Bar.Baz />;
     $[0] = t0;
   } else {
     t0 = $[0];
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/jsx-spread.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/jsx-spread.expect.md
index 0dae3baf71..ae56eb3673 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/jsx-spread.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/jsx-spread.expect.md
@@ -30,7 +30,7 @@ function Component(props) {
   const c_3 = $[3] !== t1;
   let t2;
   if (c_2 || c_3) {
-    t2 = <Component {...props} {...t1}></Component>;
+    t2 = <Component {...props} {...t1} />;
     $[2] = props;
     $[3] = t1;
     $[4] = t2;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/property-assignment.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/property-assignment.expect.md
index 0589203765..d6aa05601b 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/property-assignment.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/property-assignment.expect.md
@@ -26,7 +26,7 @@ function Component(props) {
     const y = [];
     x.y = y;
 
-    child = <Component data={y}></Component>;
+    child = <Component data={y} />;
     x.y.push(props.p0);
     $[0] = props.p0;
     $[1] = x;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/reassignment-conditional.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/reassignment-conditional.expect.md
index c7552085ba..264c35876e 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/reassignment-conditional.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/reassignment-conditional.expect.md
@@ -51,7 +51,7 @@ function Component(props) {
   const c_4 = $[4] !== y;
   let t1;
   if (c_3 || c_4) {
-    t1 = <Component x={x} y={y}></Component>;
+    t1 = <Component x={x} y={y} />;
     $[3] = x;
     $[4] = y;
     $[5] = t1;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/reassignment.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/reassignment.expect.md
index 0b3212b74d..cfd6e3b074 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/reassignment.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/reassignment.expect.md
@@ -52,7 +52,7 @@ function Component(props) {
   const c_6 = $[6] !== y;
   let t1;
   if (c_5 || c_6) {
-    t1 = <Component x={x} y={y}></Component>;
+    t1 = <Component x={x} y={y} />;
     $[5] = x;
     $[6] = y;
     $[7] = t1;
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/ssa-call-jsx-2.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/ssa-call-jsx-2.expect.md
index e658014990..cd3188fd7f 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/ssa-call-jsx-2.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/ssa-call-jsx-2.expect.md
@@ -44,7 +44,7 @@ function Component(props) {
   }
   let t0;
   if ($[2] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = <div a={a} b={b}></div>;
+    t0 = <div a={a} b={b} />;
     $[2] = t0;
   } else {
     t0 = $[2];
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/ssa-call-jsx.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/ssa-call-jsx.expect.md
index e786729615..4cf158fa08 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/ssa-call-jsx.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/ssa-call-jsx.expect.md
@@ -38,7 +38,7 @@ function Component(props) {
   }
   let t0;
   if ($[2] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = <div a={a} b={b}></div>;
+    t0 = <div a={a} b={b} />;
     $[2] = t0;
   } else {
     t0 = $[2];
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/switch-non-final-default.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/switch-non-final-default.expect.md
index f34da2a525..7a88ff0bb1 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/switch-non-final-default.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/switch-non-final-default.expect.md
@@ -71,7 +71,7 @@ function Component(props) {
   const c_4 = $[4] !== x;
   let t1;
   if (c_4) {
-    t1 = <Component data={x}></Component>;
+    t1 = <Component data={x} />;
     $[4] = x;
     $[5] = t1;
   } else {
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/switch.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/switch.expect.md
index c2940b4a9c..610f317624 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/switch.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/switch.expect.md
@@ -52,7 +52,7 @@ function Component(props) {
   const c_3 = $[3] !== x;
   let t0;
   if (c_3) {
-    t0 = <Component data={x}></Component>;
+    t0 = <Component data={x} />;
     $[3] = x;
     $[4] = t0;
   } else {
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/use-callback-simple.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/use-callback-simple.expect.md
index 27e04507db..6b1fa77f5c 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/use-callback-simple.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/use-callback-simple.expect.md
@@ -32,7 +32,7 @@ function component() {
   const c_3 = $[3] !== increment;
   let t1;
   if (c_3) {
-    t1 = <Foo onClick={increment}></Foo>;
+    t1 = <Foo onClick={increment} />;
     $[3] = increment;
     $[4] = t1;
   } else {
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/useMemo-simple.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/useMemo-simple.expect.md
index ef1baed8c5..7a15a4931d 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/useMemo-simple.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/useMemo-simple.expect.md
@@ -27,7 +27,7 @@ function component(a) {
   const c_2 = $[2] !== x;
   let t1;
   if (c_2) {
-    t1 = <Foo x={x}></Foo>;
+    t1 = <Foo x={x} />;
     $[2] = x;
     $[3] = t1;
   } else {
diff --git a/compiler/forget/src/__tests__/fixtures/disableMemoizeJsxElements/Component.expect.md b/compiler/forget/src/__tests__/fixtures/disableMemoizeJsxElements/Component.expect.md
index 9a6b460671..86ed88b104 100644
--- a/compiler/forget/src/__tests__/fixtures/disableMemoizeJsxElements/Component.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/disableMemoizeJsxElements/Component.expect.md
@@ -34,7 +34,7 @@ function Component(props) {
     t0 = $[1];
   }
   const onChange = t0;
-  return <form>{<input onChange={onChange} value={name}></input>}</form>;
+  return <form>{<input onChange={onChange} value={name} />}</form>;
 }
 
 ```