no-unreachable: allow type alias after function return

src/rules/noUnreachableRule.ts

@@ -36,8 +36,9 @@ class NoUnreachableWalker extends Lint.RuleWalker {
 
     public visitNode(node: ts.Node) {
         const previousReturned = this.hasReturned;
-        // function declarations can be hoisted -- so set hasReturned to false until we're done with the function
-        if (node.kind === ts.SyntaxKind.FunctionDeclaration) {
+        // function declarations and type alias declarations can be hoisted
+        // -- so set hasReturned to false until we're done with the function
+        if (node.kind === ts.SyntaxKind.FunctionDeclaration || node.kind === ts.SyntaxKind.TypeAliasDeclaration) {
             this.hasReturned = false;
         }
 
@@ -99,4 +100,8 @@ class NoUnreachableWalker extends Lint.RuleWalker {
         super.visitThrowStatement(node);
         this.hasReturned = true;
     }
+
+    public visitTypeAliasDeclaration(node: ts.TypeAliasDeclaration) {
+        this.visitNode(node);
+    }
 }

test/rules/no-unreachable/test.ts.lint

@@ -101,4 +101,18 @@ function f8() {
     } catch (e) {
         console.log("here");
     }
+}
+
+// valid case
+
+function f9() {
+  return 1;
+  function bar() {}
+  type Bar = string;
+}
+
+function f10() {
+  type Bar = string;
+  return 1;
+  function bar() {}
 }