Improve non-ambient class and function merge error

Author: orta

.devcontainer/Dockerfile

@@ -0,0 +1,7 @@
+# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.154.0/containers/javascript-node/.devcontainer/base.Dockerfile
+
+# [Choice] Node.js version: 14, 12, 10
+ARG VARIANT="14-buster"
+FROM mcr.microsoft.com/vscode/devcontainers/javascript-node:0-${VARIANT}
+
+RUN sudo -u node npm install -g gulp-cli

.devcontainer/devcontainer.json

@@ -0,0 +1,16 @@
+{
+    "name": "Node.js",
+    "build": {
+        "dockerfile": "Dockerfile",
+        "args": {
+            "VARIANT": "14"
+        }
+    },
+    "settings": {
+        "terminal.integrated.shell.linux": "/bin/bash"
+    },
+    "extensions": [
+        "dbaeumer.vscode-eslint"
+    ],
+    "remoteUser": "node"
+}

.dockerignore

@@ -29,6 +29,7 @@ scripts/processDiagnosticMessages.js
 scripts/produceLKG.js
 scripts/importDefinitelyTypedTests/importDefinitelyTypedTests.js
 scripts/generateLocalizedDiagnosticMessages.js
+scripts/configureLanguageServiceBuild.js
 scripts/*.js.map
 scripts/typings/
 coverage/
@@ -42,7 +43,6 @@ yarn-error.log
 .parallelperf.*
 .failed-tests
 TEST-results.xml
-package-lock.json
 tests
 .vscode
-.git
+.git

.eslintignore

@@ -1,4 +1,4 @@
 /built/local/**
 /tests/**
 /lib/**
-/src/lib/*.generated.d.ts
+/src/lib/*.generated.d.ts

.eslintrc.json

@@ -17,15 +17,35 @@
         "@typescript-eslint/adjacent-overload-signatures": "error",
         "@typescript-eslint/array-type": "error",
 
-        "camelcase": "off",
-        "@typescript-eslint/camelcase": ["error", { "properties": "never", "allow": ["^[A-Za-z][a-zA-Za-z]+_[A-Za-z]+$"] }],
+        "brace-style": "off",
+        "@typescript-eslint/brace-style": ["error", "stroustrup", { "allowSingleLine": true }],
+
+        "@typescript-eslint/naming-convention": [
+            "error",
+            { "selector": "typeLike", "format": ["PascalCase"], "filter": { "regex": "^(__String|[A-Za-z]+_[A-Za-z]+)$", "match": false } },
+            { "selector": "interface", "format": ["PascalCase"], "custom": { "regex": "^I[A-Z]", "match": false }, "filter": { "regex": "^I(Arguments|TextWriter|O([A-Z][a-z]+[A-Za-z]*)?)$", "match": false } },
+            { "selector": "variable", "format": ["camelCase", "PascalCase", "UPPER_CASE"], "leadingUnderscore": "allow", "filter": { "regex": "^(_{1,2}filename|_{1,2}dirname|_+|[A-Za-z]+_[A-Za-z]+)$", "match": false } },
+            { "selector": "function", "format": ["camelCase", "PascalCase"], "leadingUnderscore": "allow", "filter": { "regex": "^[A-Za-z]+_[A-Za-z]+$", "match": false } },
+            { "selector": "parameter", "format": ["camelCase"], "leadingUnderscore": "allow", "filter": { "regex": "^(_+|[A-Za-z]+_[A-Z][a-z]+)$", "match": false } },
+            { "selector": "method", "format": ["camelCase", "PascalCase"], "leadingUnderscore": "allow", "filter": { "regex": "^[A-Za-z]+_[A-Za-z]+$", "match": false } },
+            { "selector": "memberLike", "format": ["camelCase"], "leadingUnderscore": "allow", "filter": { "regex": "^[A-Za-z]+_[A-Za-z]+$", "match": false } },
+            { "selector": "enumMember", "format": ["camelCase", "PascalCase"], "leadingUnderscore": "allow", "filter": { "regex": "^[A-Za-z]+_[A-Za-z]+$", "match": false } },
+            { "selector": "property", "format": null }
+        ],
 
-        "@typescript-eslint/class-name-casing": "error",
         "@typescript-eslint/consistent-type-definitions": ["error", "interface"],
-        "@typescript-eslint/interface-name-prefix": "error",
+        "@typescript-eslint/consistent-type-assertions": ["error", { "assertionStyle": "as" }],
+
+        "no-duplicate-imports": "off",
+        "@typescript-eslint/no-duplicate-imports": "error",
+
         "@typescript-eslint/no-inferrable-types": "error",
         "@typescript-eslint/no-misused-new": "error",
         "@typescript-eslint/no-this-alias": "error",
+
+        "no-unused-expressions": "off",
+        "@typescript-eslint/no-unused-expressions": ["error", { "allowTernary": true }],
+
         "@typescript-eslint/prefer-for-of": "error",
         "@typescript-eslint/prefer-function-type": "error",
         "@typescript-eslint/prefer-namespace-keyword": "error",
@@ -36,6 +56,13 @@
         "semi": "off",
         "@typescript-eslint/semi": "error",
 
+        "space-before-function-paren": "off",
+        "@typescript-eslint/space-before-function-paren": ["error", {
+            "asyncArrow": "always",
+            "anonymous": "always",
+            "named": "never"
+        }],
+
         "@typescript-eslint/triple-slash-reference": "error",
         "@typescript-eslint/type-annotation-spacing": "error",
         "@typescript-eslint/unified-signatures": "error",
@@ -54,6 +81,7 @@
         "simple-indent": "error",
         "debug-assert": "error",
         "no-keywords": "error",
+        "one-namespace-per-file": "error",
 
         // eslint-plugin-import
         "import/no-extraneous-dependencies": ["error", { "optionalDependencies": false }],
@@ -65,7 +93,6 @@
         "jsdoc/check-alignment": "error",
 
         // eslint
-        "brace-style": ["error", "stroustrup", { "allowSingleLine": true }],
         "constructor-super": "error",
         "curly": ["error", "multi-line"],
         "dot-notation": "error",
@@ -74,7 +101,6 @@
         "new-parens": "error",
         "no-caller": "error",
         "no-duplicate-case": "error",
-        "no-duplicate-imports": "error",
         "no-empty": "error",
         "no-eval": "error",
         "no-extra-bind": "error",
@@ -96,7 +122,6 @@
         "no-trailing-spaces": "error",
         "no-undef-init": "error",
         "no-unsafe-finally": "error",
-        "no-unused-expressions": ["error", { "allowTernary": true }],
         "no-unused-labels": "error",
         "no-var": "error",
         "object-shorthand": "error",

.github/ISSUE_TEMPLATE/Bug_report.md

@@ -1,37 +1,73 @@
----
-name: Bug report
-about: Create a report to help us improve
-
----
-
-<!-- 🚨 STOP 🚨 𝗦𝗧𝗢𝗣 🚨 𝑺𝑻𝑶𝑷 🚨
-
-Half of all issues filed here are duplicates, answered in the FAQ, or not appropriate for the bug tracker. Even if you think you've found a *bug*, please read the FAQ first, especially the Common "Bugs" That Aren't Bugs section!
-
-Please help us by doing the following steps before logging an issue:
-  * Search: https://github.com/Microsoft/TypeScript/search?type=Issues
-  * Read the FAQ: https://github.com/Microsoft/TypeScript/wiki/FAQ
-
-Please fill in the *entire* template below.
--->
-
-<!-- Please try to reproduce the issue with `typescript@next`. It may have already been fixed. -->
-**TypeScript Version:**  3.4.0-dev.201xxxxx
-
-<!-- Search terms you tried before logging this (so others can find this issue more easily) -->
-**Search Terms:**
-
-**Code**
-
-```ts
-// A *self-contained* demonstration of the problem follows...
-// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.
-```
-
-**Expected behavior:**
-
-**Actual behavior:**
-
-**Playground Link:** <!-- A link to a TypeScript Playground "Share" link which demonstrates this behavior -->
-
-**Related Issues:** <!-- Did you find other bugs that looked similar? -->
+---
+name: Bug
+about: Create a report to help us improve TypeScript
+title: ''
+labels: ''
+assignees: ''
+---
+# Bug Report
+
+<!--
+  Please fill in each section completely. Thank you!
+-->
+
+### 🔎 Search Terms
+
+<!--
+  What search terms did you use when trying to find an existing bug report?
+  List them here so people in the future can find this one more easily.
+-->
+
+### 🕗 Version & Regression Information
+
+<!-- When did you start seeing this bug occur?
+
+"Bugs" that have existed in TS for a long time are very likely to be FAQs; refer to
+  https://github.com/Microsoft/TypeScript/wiki/FAQ#common-bugs-that-arent-bugs
+
+If possible, please try testing the nightly version of TS to see if it's already been fixed.
+For npm: `typescript@next`
+This is also the 'Nightly' version in the playground: http://www.typescriptlang.org/play/?ts=Nightly
+
+Note: The TypeScript Playground can be used to try older versions of TypeScript.
+
+Please keep and fill in the line that best applies:
+-->
+- This is a crash
+- This changed between versions ______ and _______
+- This is the behavior in every version I tried, and I reviewed the FAQ for entries about _________
+- I was unable to test this on prior versions because _______
+
+### ⏯ Playground Link
+
+<!--
+  A link to a TypeScript Playground "Share" link which shows this behavior
+
+  The TypeScript Workbench can be used for more complex setups, try
+  https://www.typescriptlang.org/dev/bug-workbench/
+
+  As a last resort, you can link to a repo, but these will be slower for us to investigate.
+-->
+[Playground link with relevant code](https://www.typescriptlang.org/play?#code/PTAEFkE9QYwewCYFNQHM5IM6gBZIE5JA)
+
+### 💻 Code
+
+<!-- Please post the relevant code sample here as well-->
+```ts
+// We can quickly address your report if:
+//  - The code sample is short. Nearly all TypeScript bugs can be demonstrated in 20-30 lines of code!
+//  - It doesn't use external libraries. These are often issues with the type definitions rather than TypeScript bugs.
+//  - The incorrectness of the behavior is readily apparent from reading the sample.
+// Reports are slower to investigate if:
+//  - We have to pare too much extraneous code.
+//  - We have to clone a large repo and validate that the problem isn't elsewhere.
+//  - The sample is confusing or doesn't clearly demonstrate what's wrong.
+```
+
+### 🙁 Actual behavior
+
+<!-- What happened, and why it was wrong -->
+
+### 🙂 Expected behavior
+
+<!-- What you expected to happen instead, and why -->

.github/ISSUE_TEMPLATE/Feature_request.md

@@ -1,45 +1,59 @@
----
-name: Feature request
-about: Suggest an idea for this project
-
----
-
-<!-- 🚨 STOP 🚨 𝗦𝗧𝗢𝗣 🚨 𝑺𝑻𝑶𝑷 🚨
-
-Half of all issues filed here are duplicates, answered in the FAQ, or not appropriate for the bug tracker.
-
-Please help us by doing the following steps before logging an issue:
-  * Search: https://github.com/Microsoft/TypeScript/search?type=Issues
-  * Read the FAQ, especially the "Common Feature Requests" section: https://github.com/Microsoft/TypeScript/wiki/FAQ
-
--->
-
-## Search Terms
-
-<!-- List of keywords you searched for before creating this issue. Write them down here so that others can find this suggestion more easily -->
-
-## Suggestion
-
-<!-- A summary of what you'd like to see added or changed -->
-
-## Use Cases
-
-<!--
-What do you want to use this for?
-What shortcomings exist with current approaches?
--->
-
-## Examples
-
-<!-- Show how this would be used and what the behavior would be -->
-
-## Checklist
-
-My suggestion meets these guidelines:
-
-* [ ] This wouldn't be a breaking change in existing TypeScript/JavaScript code
-* [ ] This wouldn't change the runtime behavior of existing JavaScript code
-* [ ] This could be implemented without emitting different JS based on the types of the expressions
-* [ ] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
-* [ ] This feature would agree with the rest of [TypeScript's Design Goals](https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals).
-
+---
+name: Feature Request
+about: Suggest an idea
+title: ''
+labels: ''
+assignees: ''
+---
+# Suggestion
+
+<!--
+  Please fill in each section completely. Thank you!
+-->
+
+## 🔍 Search Terms
+
+<!--
+  💡 Did you know? TypeScript has over 2,000 open suggestions!
+  🔎 Please search thoroughly before logging new feature requests as most common ideas already have a proposal in progress.
+  The "Common Feature Requests" section of the FAQ lists many popular requests: https://github.com/Microsoft/TypeScript/wiki/FAQ#common-feature-requests
+
+  Replace the text below:
+-->
+
+List of keywords you searched for before creating this issue. Write them down here so that others can find this suggestion more easily and help provide feedback.
+
+## ✅ Viability Checklist
+
+<!--
+   Suggestions that don't meet all these criteria are very, very unlikely to be accepted.
+   We always recommend reviewing the TypeScript design goals before investing time writing
+   a proposal for ideas outside the scope of the project.
+-->
+My suggestion meets these guidelines:
+
+* [ ] This wouldn't be a breaking change in existing TypeScript/JavaScript code
+* [ ] This wouldn't change the runtime behavior of existing JavaScript code
+* [ ] This could be implemented without emitting different JS based on the types of the expressions
+* [ ] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
+* [ ] This feature would agree with the rest of [TypeScript's Design Goals](https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals).
+
+
+## ⭐ Suggestion
+
+<!-- A summary of what you'd like to see added or changed -->
+
+## 📃 Motivating Example
+
+<!--
+  If you were announcing this feature in a blog post, what's a short explanation that shows
+  a developer why this feature improves the language?
+-->
+
+## 💻 Use Cases
+
+<!--
+  What do you want to use this for?
+  What shortcomings exist with current approaches?
+  What workarounds are you using in the meantime?
+-->

.github/ISSUE_TEMPLATE/Question.md

@@ -0,0 +1,19 @@
+--- 
+blank_issues_enabled: false
+contact_links: 
+  - 
+    about: "Please ask and answer usage questions on Stack Overflow."
+    name: Question
+    url: "https://stackoverflow.com/questions/tagged/typescript"
+  - 
+    about: "Alternatively, you can use the TypeScript Community Discord."
+    name: Chat
+    url: "https://discord.gg/typescript"
+  - 
+    about: "Please check the FAQ before filing new issues"
+    name: "TypeScript FAQ"
+    url: "https://github.com/microsoft/TypeScript/wiki/FAQ"
+  - 
+    about: "Please raise issues about the site on its own repo."
+    name: Website
+    url: "https://github.com/microsoft/TypeScript-Website/issues/new"