Support null as value

Author: nikeee

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

@@ -540,7 +540,7 @@ function evaluateInstruction(
 
         const expressionValue = subExprValue.value;
         if (
-          typeof expressionValue === 'object' ||
+          (typeof expressionValue === 'object' && expressionValue !== null) ||
           typeof expressionValue === 'symbol' ||
           typeof expressionValue === 'function'
         ) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/constant-propagation-template-literal.expect.md

@@ -99,7 +99,7 @@ function foo() {
           `${[1, 2, 3]}`,
           "true",
           "false",
-          `${null}`,
+          "null",
           `${undefined}`,
           "1234567890",
           "0123456789",