From 148bfb1cf03b86590ed6ec3c4a44ef15d8904942 Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Wed, 13 May 2020 18:07:03 -0400
Subject: [PATCH 1/2] fix wrapping classes when targeting ESNext

---
 src/compiler/transformers/ts.ts                 |  7 ++++++-
 .../reference/thisInClassBodyStaticESNext.js    | 17 +++++++----------
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 7f848685aec36..45f49c5a905e0 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -23,10 +23,10 @@ namespace ts {
         IsNamedExternalExport = 1 << 4,
         IsDefaultExternalExport = 1 << 5,
         IsDerivedClass = 1 << 6,
+        UseImmediatelyInvokedFunctionExpression = 1 << 7,
 
         HasAnyDecorators = HasConstructorDecorators | HasMemberDecorators,
         NeedsName = HasStaticInitializedProperties | HasMemberDecorators,
-        UseImmediatelyInvokedFunctionExpression = HasAnyDecorators | HasStaticInitializedProperties,
         IsExported = IsExportOfNamespace | IsDefaultExternalExport | IsNamedExternalExport,
     }
 
@@ -595,6 +595,11 @@ namespace ts {
             if (isExportOfNamespace(node)) facts |= ClassFacts.IsExportOfNamespace;
             else if (isDefaultExternalModuleExport(node)) facts |= ClassFacts.IsDefaultExternalExport;
             else if (isNamedExternalModuleExport(node)) facts |= ClassFacts.IsNamedExternalExport;
+            if (facts & ClassFacts.HasAnyDecorators) facts |= ClassFacts.UseImmediatelyInvokedFunctionExpression;
+            if (facts & ClassFacts.HasStaticInitializedProperties) {
+                if (languageVersion < ScriptTarget.ESNext) facts |= ClassFacts.UseImmediatelyInvokedFunctionExpression;
+                else if (languageVersion === ScriptTarget.ESNext && !compilerOptions.useDefineForClassFields) facts |= ClassFacts.UseImmediatelyInvokedFunctionExpression;
+            }
             return facts;
         }
 
diff --git a/tests/baselines/reference/thisInClassBodyStaticESNext.js b/tests/baselines/reference/thisInClassBodyStaticESNext.js
index 6ad51b36a7385..7f061b12a4149 100644
--- a/tests/baselines/reference/thisInClassBodyStaticESNext.js
+++ b/tests/baselines/reference/thisInClassBodyStaticESNext.js
@@ -11,13 +11,10 @@ class Foo {
 
 //// [thisInClassBodyStaticESNext.js]
 // all are allowed with es-compliant class field emit
-let Foo = /** @class */ (() => {
-    class Foo {
-        x = this;
-        static t = this;
-        static at = () => this;
-        static ft = function () { return this; };
-        static mt() { return this; }
-    }
-    return Foo;
-})();
+class Foo {
+    x = this;
+    static t = this;
+    static at = () => this;
+    static ft = function () { return this; };
+    static mt() { return this; }
+}

From cef1fcdfc6130d25e9d50bcfb89c95ff117dfcc6 Mon Sep 17 00:00:00 2001
From: Ryan Delaney <rdel@google.com>
Date: Fri, 15 May 2020 18:04:07 +0000
Subject: [PATCH 2/2] Add addOptimizationHints compiler option

---
 src/compiler/commandLineParser.ts             |  7 ++++
 src/compiler/diagnosticMessages.json          |  4 ++
 src/compiler/transformers/ts.ts               | 17 +++++---
 src/compiler/types.ts                         |  1 +
 .../reference/addOptimizationHints.errors.txt | 23 +++++++++++
 .../reference/addOptimizationHints.js         | 40 +++++++++++++++++++
 .../reference/addOptimizationHints.symbols    | 32 +++++++++++++++
 .../reference/addOptimizationHints.types      | 35 ++++++++++++++++
 .../addOptimizationHintsFalse.errors.txt      | 23 +++++++++++
 .../reference/addOptimizationHintsFalse.js    | 34 ++++++++++++++++
 .../addOptimizationHintsFalse.symbols         | 32 +++++++++++++++
 .../reference/addOptimizationHintsFalse.types | 35 ++++++++++++++++
 .../reference/api/tsserverlibrary.d.ts        |  1 +
 tests/baselines/reference/api/typescript.d.ts |  1 +
 .../addOptimizationHints/tsconfig.json        |  5 +++
 tests/cases/compiler/addOptimizationHints.ts  | 20 ++++++++++
 .../compiler/addOptimizationHintsFalse.ts     | 20 ++++++++++
 17 files changed, 325 insertions(+), 5 deletions(-)
 create mode 100644 tests/baselines/reference/addOptimizationHints.errors.txt
 create mode 100644 tests/baselines/reference/addOptimizationHints.js
 create mode 100644 tests/baselines/reference/addOptimizationHints.symbols
 create mode 100644 tests/baselines/reference/addOptimizationHints.types
 create mode 100644 tests/baselines/reference/addOptimizationHintsFalse.errors.txt
 create mode 100644 tests/baselines/reference/addOptimizationHintsFalse.js
 create mode 100644 tests/baselines/reference/addOptimizationHintsFalse.symbols
 create mode 100644 tests/baselines/reference/addOptimizationHintsFalse.types
 create mode 100644 tests/baselines/reference/showConfig/Shows tsconfig for single option/addOptimizationHints/tsconfig.json
 create mode 100644 tests/cases/compiler/addOptimizationHints.ts
 create mode 100644 tests/cases/compiler/addOptimizationHintsFalse.ts

diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 8d4f332032d6f..d1dc91494eff2 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -986,6 +986,13 @@ namespace ts {
             category: Diagnostics.Advanced_Options,
             description: Diagnostics.Resolve_keyof_to_string_valued_property_names_only_no_numbers_or_symbols,
         },
+        {
+          name: "addOptimizationHints",
+          type: "boolean",
+          affectsEmit: true,
+          category: Diagnostics.Advanced_Options,
+          description: Diagnostics.Resolve_keyof_to_string_valued_property_names_only_no_numbers_or_symbols,
+        },
         {
             // A list of plugins to load in the language service
             name: "plugins",
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 2dfabe540adf7..845081e7a57a7 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -4400,6 +4400,10 @@
         "category": "Error",
         "code": 6233
     },
+    "Emit code hints for optimizers and minifiers.": {
+      "category": "Message",
+      "code": 6234
+    },
 
     "Projects to reference": {
         "category": "Message",
diff --git a/src/compiler/transformers/ts.ts b/src/compiler/transformers/ts.ts
index 45f49c5a905e0..a6bc7dcf898ac 100644
--- a/src/compiler/transformers/ts.ts
+++ b/src/compiler/transformers/ts.ts
@@ -585,6 +585,17 @@ namespace ts {
             return parameter.decorators !== undefined && parameter.decorators.length > 0;
         }
 
+        function shouldWrapClassWithIIFE(facts: ClassFacts) {
+          if (compilerOptions.addOptimizationHints === false) return false;
+          if (facts & ClassFacts.HasAnyDecorators) return true;
+          if (facts & ClassFacts.HasStaticInitializedProperties) {
+              if (languageVersion < ScriptTarget.ESNext) return true;
+              else if (languageVersion === ScriptTarget.ESNext && !compilerOptions.useDefineForClassFields) return true;
+          }
+
+          return false;
+        }
+
         function getClassFacts(node: ClassDeclaration, staticProperties: readonly PropertyDeclaration[]) {
             let facts = ClassFacts.None;
             if (some(staticProperties)) facts |= ClassFacts.HasStaticInitializedProperties;
@@ -595,11 +606,7 @@ namespace ts {
             if (isExportOfNamespace(node)) facts |= ClassFacts.IsExportOfNamespace;
             else if (isDefaultExternalModuleExport(node)) facts |= ClassFacts.IsDefaultExternalExport;
             else if (isNamedExternalModuleExport(node)) facts |= ClassFacts.IsNamedExternalExport;
-            if (facts & ClassFacts.HasAnyDecorators) facts |= ClassFacts.UseImmediatelyInvokedFunctionExpression;
-            if (facts & ClassFacts.HasStaticInitializedProperties) {
-                if (languageVersion < ScriptTarget.ESNext) facts |= ClassFacts.UseImmediatelyInvokedFunctionExpression;
-                else if (languageVersion === ScriptTarget.ESNext && !compilerOptions.useDefineForClassFields) facts |= ClassFacts.UseImmediatelyInvokedFunctionExpression;
-            }
+            if (shouldWrapClassWithIIFE(facts)) facts |= ClassFacts.UseImmediatelyInvokedFunctionExpression;
             return facts;
         }
 
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 54d889b2ff4fc..415ee85a83a62 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -5133,6 +5133,7 @@ namespace ts {
     export type CompilerOptionsValue = string | number | boolean | (string | number)[] | string[] | MapLike<string[]> | PluginImport[] | ProjectReference[] | null | undefined;
 
     export interface CompilerOptions {
+        addOptimizationHints?: boolean;
         /*@internal*/ all?: boolean;
         allowJs?: boolean;
         /*@internal*/ allowNonTsExtensions?: boolean;
diff --git a/tests/baselines/reference/addOptimizationHints.errors.txt b/tests/baselines/reference/addOptimizationHints.errors.txt
new file mode 100644
index 0000000000000..ac09a4a787f1e
--- /dev/null
+++ b/tests/baselines/reference/addOptimizationHints.errors.txt
@@ -0,0 +1,23 @@
+tests/cases/compiler/addOptimizationHints.ts(13,2): error TS2304: Cannot find name 'decorate'.
+
+
+==== tests/cases/compiler/addOptimizationHints.ts (1 errors) ====
+    class HasNoStatics {
+      value: unknown;
+      method() {}
+    }
+    
+    class HasStatic {
+      static value = 0;
+      static someMethod() {}
+    
+      method() {}
+    }
+    
+    @decorate
+     ~~~~~~~~
+!!! error TS2304: Cannot find name 'decorate'.
+    class HasDecorator {
+      method() {}
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/addOptimizationHints.js b/tests/baselines/reference/addOptimizationHints.js
new file mode 100644
index 0000000000000..7b1a2cc46a8dd
--- /dev/null
+++ b/tests/baselines/reference/addOptimizationHints.js
@@ -0,0 +1,40 @@
+//// [addOptimizationHints.ts]
+class HasNoStatics {
+  value: unknown;
+  method() {}
+}
+
+class HasStatic {
+  static value = 0;
+  static someMethod() {}
+
+  method() {}
+}
+
+@decorate
+class HasDecorator {
+  method() {}
+}
+
+
+//// [addOptimizationHints.js]
+class HasNoStatics {
+    method() { }
+}
+let HasStatic = /** @class */ (() => {
+    class HasStatic {
+        static someMethod() { }
+        method() { }
+    }
+    HasStatic.value = 0;
+    return HasStatic;
+})();
+let HasDecorator = /** @class */ (() => {
+    let HasDecorator = class HasDecorator {
+        method() { }
+    };
+    HasDecorator = __decorate([
+        decorate
+    ], HasDecorator);
+    return HasDecorator;
+})();
diff --git a/tests/baselines/reference/addOptimizationHints.symbols b/tests/baselines/reference/addOptimizationHints.symbols
new file mode 100644
index 0000000000000..d5eabf8eb4477
--- /dev/null
+++ b/tests/baselines/reference/addOptimizationHints.symbols
@@ -0,0 +1,32 @@
+=== tests/cases/compiler/addOptimizationHints.ts ===
+class HasNoStatics {
+>HasNoStatics : Symbol(HasNoStatics, Decl(addOptimizationHints.ts, 0, 0))
+
+  value: unknown;
+>value : Symbol(HasNoStatics.value, Decl(addOptimizationHints.ts, 0, 20))
+
+  method() {}
+>method : Symbol(HasNoStatics.method, Decl(addOptimizationHints.ts, 1, 17))
+}
+
+class HasStatic {
+>HasStatic : Symbol(HasStatic, Decl(addOptimizationHints.ts, 3, 1))
+
+  static value = 0;
+>value : Symbol(HasStatic.value, Decl(addOptimizationHints.ts, 5, 17))
+
+  static someMethod() {}
+>someMethod : Symbol(HasStatic.someMethod, Decl(addOptimizationHints.ts, 6, 19))
+
+  method() {}
+>method : Symbol(HasStatic.method, Decl(addOptimizationHints.ts, 7, 24))
+}
+
+@decorate
+class HasDecorator {
+>HasDecorator : Symbol(HasDecorator, Decl(addOptimizationHints.ts, 10, 1))
+
+  method() {}
+>method : Symbol(HasDecorator.method, Decl(addOptimizationHints.ts, 13, 20))
+}
+
diff --git a/tests/baselines/reference/addOptimizationHints.types b/tests/baselines/reference/addOptimizationHints.types
new file mode 100644
index 0000000000000..6eb0802817977
--- /dev/null
+++ b/tests/baselines/reference/addOptimizationHints.types
@@ -0,0 +1,35 @@
+=== tests/cases/compiler/addOptimizationHints.ts ===
+class HasNoStatics {
+>HasNoStatics : HasNoStatics
+
+  value: unknown;
+>value : unknown
+
+  method() {}
+>method : () => void
+}
+
+class HasStatic {
+>HasStatic : HasStatic
+
+  static value = 0;
+>value : number
+>0 : 0
+
+  static someMethod() {}
+>someMethod : () => void
+
+  method() {}
+>method : () => void
+}
+
+@decorate
+>decorate : any
+
+class HasDecorator {
+>HasDecorator : HasDecorator
+
+  method() {}
+>method : () => void
+}
+
diff --git a/tests/baselines/reference/addOptimizationHintsFalse.errors.txt b/tests/baselines/reference/addOptimizationHintsFalse.errors.txt
new file mode 100644
index 0000000000000..bccd89840cd95
--- /dev/null
+++ b/tests/baselines/reference/addOptimizationHintsFalse.errors.txt
@@ -0,0 +1,23 @@
+tests/cases/compiler/addOptimizationHintsFalse.ts(13,2): error TS2304: Cannot find name 'decorate'.
+
+
+==== tests/cases/compiler/addOptimizationHintsFalse.ts (1 errors) ====
+    class HasNoStatics {
+      value: unknown;
+      method() {}
+    }
+    
+    class HasStatic {
+      static value = 0;
+      static someMethod() {}
+    
+      method() {}
+    }
+    
+    @decorate
+     ~~~~~~~~
+!!! error TS2304: Cannot find name 'decorate'.
+    class HasDecorator {
+      method() {}
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/addOptimizationHintsFalse.js b/tests/baselines/reference/addOptimizationHintsFalse.js
new file mode 100644
index 0000000000000..2a495445ff1c3
--- /dev/null
+++ b/tests/baselines/reference/addOptimizationHintsFalse.js
@@ -0,0 +1,34 @@
+//// [addOptimizationHintsFalse.ts]
+class HasNoStatics {
+  value: unknown;
+  method() {}
+}
+
+class HasStatic {
+  static value = 0;
+  static someMethod() {}
+
+  method() {}
+}
+
+@decorate
+class HasDecorator {
+  method() {}
+}
+
+
+//// [addOptimizationHintsFalse.js]
+class HasNoStatics {
+    method() { }
+}
+class HasStatic {
+    static someMethod() { }
+    method() { }
+}
+HasStatic.value = 0;
+let HasDecorator = class HasDecorator {
+    method() { }
+};
+HasDecorator = __decorate([
+    decorate
+], HasDecorator);
diff --git a/tests/baselines/reference/addOptimizationHintsFalse.symbols b/tests/baselines/reference/addOptimizationHintsFalse.symbols
new file mode 100644
index 0000000000000..9d0750fd0c9bd
--- /dev/null
+++ b/tests/baselines/reference/addOptimizationHintsFalse.symbols
@@ -0,0 +1,32 @@
+=== tests/cases/compiler/addOptimizationHintsFalse.ts ===
+class HasNoStatics {
+>HasNoStatics : Symbol(HasNoStatics, Decl(addOptimizationHintsFalse.ts, 0, 0))
+
+  value: unknown;
+>value : Symbol(HasNoStatics.value, Decl(addOptimizationHintsFalse.ts, 0, 20))
+
+  method() {}
+>method : Symbol(HasNoStatics.method, Decl(addOptimizationHintsFalse.ts, 1, 17))
+}
+
+class HasStatic {
+>HasStatic : Symbol(HasStatic, Decl(addOptimizationHintsFalse.ts, 3, 1))
+
+  static value = 0;
+>value : Symbol(HasStatic.value, Decl(addOptimizationHintsFalse.ts, 5, 17))
+
+  static someMethod() {}
+>someMethod : Symbol(HasStatic.someMethod, Decl(addOptimizationHintsFalse.ts, 6, 19))
+
+  method() {}
+>method : Symbol(HasStatic.method, Decl(addOptimizationHintsFalse.ts, 7, 24))
+}
+
+@decorate
+class HasDecorator {
+>HasDecorator : Symbol(HasDecorator, Decl(addOptimizationHintsFalse.ts, 10, 1))
+
+  method() {}
+>method : Symbol(HasDecorator.method, Decl(addOptimizationHintsFalse.ts, 13, 20))
+}
+
diff --git a/tests/baselines/reference/addOptimizationHintsFalse.types b/tests/baselines/reference/addOptimizationHintsFalse.types
new file mode 100644
index 0000000000000..5e73d696d3516
--- /dev/null
+++ b/tests/baselines/reference/addOptimizationHintsFalse.types
@@ -0,0 +1,35 @@
+=== tests/cases/compiler/addOptimizationHintsFalse.ts ===
+class HasNoStatics {
+>HasNoStatics : HasNoStatics
+
+  value: unknown;
+>value : unknown
+
+  method() {}
+>method : () => void
+}
+
+class HasStatic {
+>HasStatic : HasStatic
+
+  static value = 0;
+>value : number
+>0 : 0
+
+  static someMethod() {}
+>someMethod : () => void
+
+  method() {}
+>method : () => void
+}
+
+@decorate
+>decorate : any
+
+class HasDecorator {
+>HasDecorator : HasDecorator
+
+  method() {}
+>method : () => void
+}
+
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 2c7742fb88b97..bfa9e68a3f7ed 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -2651,6 +2651,7 @@ declare namespace ts {
     }
     export type CompilerOptionsValue = string | number | boolean | (string | number)[] | string[] | MapLike<string[]> | PluginImport[] | ProjectReference[] | null | undefined;
     export interface CompilerOptions {
+        addOptimizationHints?: boolean;
         allowJs?: boolean;
         allowSyntheticDefaultImports?: boolean;
         allowUmdGlobalAccess?: boolean;
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index c901f86e38499..3ff058b7e8948 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -2651,6 +2651,7 @@ declare namespace ts {
     }
     export type CompilerOptionsValue = string | number | boolean | (string | number)[] | string[] | MapLike<string[]> | PluginImport[] | ProjectReference[] | null | undefined;
     export interface CompilerOptions {
+        addOptimizationHints?: boolean;
         allowJs?: boolean;
         allowSyntheticDefaultImports?: boolean;
         allowUmdGlobalAccess?: boolean;
diff --git a/tests/baselines/reference/showConfig/Shows tsconfig for single option/addOptimizationHints/tsconfig.json b/tests/baselines/reference/showConfig/Shows tsconfig for single option/addOptimizationHints/tsconfig.json
new file mode 100644
index 0000000000000..20b45590dbe5e
--- /dev/null
+++ b/tests/baselines/reference/showConfig/Shows tsconfig for single option/addOptimizationHints/tsconfig.json	
@@ -0,0 +1,5 @@
+{
+    "compilerOptions": {
+        "addOptimizationHints": true
+    }
+}
diff --git a/tests/cases/compiler/addOptimizationHints.ts b/tests/cases/compiler/addOptimizationHints.ts
new file mode 100644
index 0000000000000..b6bbcd2322cde
--- /dev/null
+++ b/tests/cases/compiler/addOptimizationHints.ts
@@ -0,0 +1,20 @@
+// @target: ES2015
+// @experimentalDecorators: true
+// @noemithelpers: true
+// @addOptimizationHints: true
+class HasNoStatics {
+  value: unknown;
+  method() {}
+}
+
+class HasStatic {
+  static value = 0;
+  static someMethod() {}
+
+  method() {}
+}
+
+@decorate
+class HasDecorator {
+  method() {}
+}
diff --git a/tests/cases/compiler/addOptimizationHintsFalse.ts b/tests/cases/compiler/addOptimizationHintsFalse.ts
new file mode 100644
index 0000000000000..f609662c82ca0
--- /dev/null
+++ b/tests/cases/compiler/addOptimizationHintsFalse.ts
@@ -0,0 +1,20 @@
+// @target: ES2015
+// @experimentalDecorators: true
+// @noemithelpers: true
+// @addOptimizationHints: false
+class HasNoStatics {
+  value: unknown;
+  method() {}
+}
+
+class HasStatic {
+  static value = 0;
+  static someMethod() {}
+
+  method() {}
+}
+
+@decorate
+class HasDecorator {
+  method() {}
+}