Update issue templates (#48261)

.github/ISSUE_TEMPLATE/Bug_report.md

@@ -4,7 +4,9 @@ about: Create a report to help us improve TypeScript
 title: ''
 labels: ''
 assignees: ''
+
 ---
+
 # Bug Report
 
 <!--

.github/ISSUE_TEMPLATE/Feature_request.md

@@ -4,7 +4,9 @@ about: Suggest an idea
 title: ''
 labels: ''
 assignees: ''
+
 ---
+
 # Suggestion
 
 <!--

.github/ISSUE_TEMPLATE/lib_change.md

@@ -1,55 +1,58 @@
----
-name: Library change
-about: Fix or improve issues with built-in type definitions like `lib.dom.d.ts`, `lib.es6.d.ts`, etc.
-title: ''
-labels: ''
-assignees: ''
----
-# lib Update Request
-
-<!--
-  Please fill in each section completely. Thank you!
-
-  Are you here for one of these commonly-requested lib changes?
-    * Object.keys - see https://stackoverflow.com/questions/55012174/
-    * Array methods - see https://github.com/microsoft/TypeScript/issues/36554
-    * parseInt, parseFloat, isFinite, isNaN, etc. - see https://github.com/microsoft/TypeScript/issues/4002
-
-  The DOM lib is maintained elsewhere and you can skip a step by filing issues/PRs for the DOM at that repo.
-  See https://github.com/microsoft/TypeScript-DOM-lib-generator
--->
-
-## Configuration Check
-
-<!--
-  If you're missing common new methods like Array.includes, you may have a misconfigured project.
-  Try setting `lib: "es2020"` and checking whether the type you want is present.
-  You can diagnose further by running `tsc` with `--listFilesOnly` or `--showConfig`.
-
-  Conversely, if you are seeing built-in methods you expect to *not* see, check your 'lib' setting
-  or review your dependencies for lib/reference directives that might be polluting
-  your global scope. This is common when using the 'node' type library. See https://github.com/microsoft/TypeScript/issues/40184
-
-  Replace the text below:
--->
-My compilation *target* is `ES2015` and my *lib* is `the default`.
-
-## Missing / Incorrect Definition
-
-<!--
-  What property, method, function, etc is missing or incorrect?
--->
-
-## Sample Code
-
-<!--
-  What's some code using this that should work, but doesn't?
--->
-
-## Documentation Link
-
-<!--
-  Link to relevant documentation (e.g. MDN, W3C, ECMAScript Spec) to consult for this property.
-  Note that lib.dom.d.ts intentionally does not include browser-specific extensions
-   or early experimental features.
--->
+---
+name: Library change
+about: Fix or improve issues with built-in type definitions like `lib.dom.d.ts`, `lib.es6.d.ts`,
+  etc.
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+# lib Update Request
+
+<!--
+  Please fill in each section completely. Thank you!
+
+  Are you here for one of these commonly-requested lib changes?
+    * Object.keys - see https://stackoverflow.com/questions/55012174/
+    * Array methods - see https://github.com/microsoft/TypeScript/issues/36554
+    * parseInt, parseFloat, isFinite, isNaN, etc. - see https://github.com/microsoft/TypeScript/issues/4002
+
+  The DOM lib is maintained elsewhere and you can skip a step by filing issues/PRs for the DOM at that repo.
+  See https://github.com/microsoft/TypeScript-DOM-lib-generator
+-->
+
+## Configuration Check
+
+<!--
+  If you're missing common new methods like Array.includes, you may have a misconfigured project.
+  Try setting `lib: "es2020"` and checking whether the type you want is present.
+  You can diagnose further by running `tsc` with `--listFilesOnly` or `--showConfig`.
+
+  Conversely, if you are seeing built-in methods you expect to *not* see, check your 'lib' setting
+  or review your dependencies for lib/reference directives that might be polluting
+  your global scope. This is common when using the 'node' type library. See https://github.com/microsoft/TypeScript/issues/40184
+
+  Replace the text below:
+-->
+My compilation *target* is `ES2015` and my *lib* is `the default`.
+
+## Missing / Incorrect Definition
+
+<!--
+  What property, method, function, etc is missing or incorrect?
+-->
+
+## Sample Code
+
+<!--
+  What's some code using this that should work, but doesn't?
+-->
+
+## Documentation Link
+
+<!--
+  Link to relevant documentation (e.g. MDN, W3C, ECMAScript Spec) to consult for this property.
+  Note that lib.dom.d.ts intentionally does not include browser-specific extensions
+   or early experimental features.
+-->

.github/ISSUE_TEMPLATE/types-not-correct-in-with-callback.md

@@ -0,0 +1,47 @@
+---
+name: Types Not Correct in/with Callback
+about: TypeScript assuming the wrong type either after a callback runs, or within
+  a callback
+title: ''
+labels: Duplicate
+assignees: ''
+
+---
+
+TypeScript has two narrowing-related behaviors that are both intentional. Please do not log additional bugs on this; see #9998 for more discussion.
+
+The first is that *narrowings are not respected in callbacks*. In other words:
+```ts
+function fn(obj: { name: string | number }) {
+  if (typeof obj.name === "string") {
+    // Errors
+    window.setTimeout(() => console.log(obj.name.toLowerCase());
+  }
+}
+```
+This is intentional since the value of `obj.name` "could" change types between when the narrowing occurred and when the callback was invoke. See also #11498
+
+The second is that *function calls do not reset narrowings*. In other words:
+```ts
+function fn(obj: { name: string | number }) {
+  if (typeof obj.name === "string") {
+    console.log("Here");
+    // Does not error
+    console.log(obj.name.toLowerCase());
+  }
+}
+```
+This is intentional behavior, *even though `console.log` could have mutated obj*. This rule is consistently applied, even with the function is in-principle inspectable to actually have side effects
+```ts
+function fn(obj: { name: string | number }) {
+  if (typeof obj.name === "string") {
+    mut();
+    // Does not error
+    console.log(obj.name.toLowerCase());
+  }
+
+  function mut() {
+    obj.name = 42;
+  }
+}
+```