Fix error in member expr on LHS of reactive statement with TS

.changeset/long-rabbits-remain.md

@@ -0,0 +1,5 @@
+---
+"svelte-eslint-parser": patch
+---
+
+Fix error in member expr on LHS of reactive statement with TS

src/parser/analyze-type/index.ts

@@ -53,7 +53,14 @@ function appendDeclareSvelteVarsTypesFromAST(
           node.label.name !== "$" ||
           parent !== result.ast ||
           node.body.type !== "ExpressionStatement" ||
-          node.body.expression.type !== "AssignmentExpression"
+          node.body.expression.type !== "AssignmentExpression" ||
+          // Must be a pattern that can be used in the LHS of variable declarations.
+          // https://github.com/ota-meshi/svelte-eslint-parser/issues/213
+          (node.body.expression.left.type !== "Identifier" &&
+            node.body.expression.left.type !== "ArrayPattern" &&
+            node.body.expression.left.type !== "ObjectPattern" &&
+            node.body.expression.left.type !== "AssignmentPattern" &&
+            node.body.expression.left.type !== "RestElement")
         ) {
           return;
         }

tests/fixtures/parser/ast/ts-not-reactive01-input.svelte

@@ -0,0 +1,6 @@
+<script lang="ts">
+const num = 42
+const obj:{ foo?: number } = {}
+$: obj.foo = num
+</script>
+{obj.foo}