Fixing nested ternaries

compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Pipeline.ts

@@ -189,9 +189,17 @@ function runWithEnvironment(
 
   assertConsistentIdentifiers(hir);
 
+  const wasTernaryConstantPropagationEnabled =
+    env.config.enableTernaryConstantPropagation;
+  env.config.enableTernaryConstantPropagation = false;
   constantPropagation(hir);
   log({kind: 'hir', name: 'ConstantPropagation', value: hir});
 
+  env.config.enableTernaryConstantPropagation =
+    wasTernaryConstantPropagationEnabled;
+  constantPropagation(hir);
+  log({kind: 'hir', name: 'ConstantPropagationTernary', value: hir});
+
   inferTypes(hir);
   log({kind: 'hir', name: 'InferTypes', value: hir});
 

compiler/packages/babel-plugin-react-compiler/src/Optimization/ConstantPropagation.ts

@@ -182,6 +182,7 @@ function applyConstantPropagation(
                */
               branchBlock.terminal.consequent
             : branchBlock.terminal.alternate;
+          block.kind = 'block';
           block.terminal = {
             kind: 'goto',
             variant: GotoVariant.Break,
@@ -190,7 +191,13 @@ function applyConstantPropagation(
             loc: terminal.loc,
           };
 
-          block.kind = 'block';
+          const fallthrough = fn.body.blocks.get(
+            branchBlock.terminal.fallthrough,
+          );
+
+          if (fallthrough?.terminal.kind == 'goto') {
+            fallthrough.kind = 'block';
+          }
 
           const consequent = fn.body.blocks.get(
             branchBlock.terminal.consequent,

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/constant-propagation-ternary-unary.js

@@ -4,7 +4,7 @@ import {Stringify} from 'shared-runtime';
 function foo() {
   let _b;
   const b = true;
-  _b = !b ? 'bar' : false ? 'foo' : 'baz';
+  _b = !b ? 'bar' : 'baz';
 
   return (
     <Stringify

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/memoize-value-block-value-conditional.expect.md

@@ -22,12 +22,14 @@ import { c as _c } from "react/compiler-runtime";
 function Foo(props) {
   const $ = _c(1);
   let x;
+  let t0;
   if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-    true ? (x = []) : (x = {});
-    $[0] = x;
+    t0 = [];
+    $[0] = t0;
   } else {
-    x = $[0];
+    t0 = $[0];
   }
+  x = t0;
   return x;
 }