Parse this argument in TypeScript function. (#1173)

Summary: Parse `this` argument in TypeScript function. Pull Request resolved: #1173 Test Plan: Unit tests added. Reviewed By: neildhar Differential Revision: D50666819 Pulled By: avp fbshipit-source-id: 1d61361605e5530ee91cf6105a2cc3e85cbb82af
facebook · Oct 26, 2023 · 04faa3f · 04faa3f
1 parent 2305173
commit 04faa3f
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Showing 5 changed files with 150 additions and 4 deletions.
diff --git a/lib/Parser/JSParserImpl-ts.cpp b/lib/Parser/JSParserImpl-ts.cpp
@@ -240,6 +240,28 @@ Optional<ESTree::Node *> JSParserImpl::parseTSFunctionOrParenthesizedType(
   ESTree::Node *type = nullptr;
   ESTree::NodeList params{};
 
+  if (check(TokenKind::rw_this)) {
+    OptValue<TokenKind> optNext = lexer_.lookahead1(None);
+    if (optNext.hasValue() && *optNext == TokenKind::colon) {
+      SMLoc thisStart = advance(JSLexer::GrammarContext::Type).Start;
+      advance(JSLexer::GrammarContext::Type);
+      CHECK_RECURSION;
+      auto typeAnnotation = parseTypeAnnotationTS();
+      if (!typeAnnotation)
+        return None;
+
+      params.push_back(*setLocation(
+          thisStart,
+          getPrevTokenEndLoc(),
+          new (context_) ESTree::IdentifierNode(
+              thisIdent_, *typeAnnotation, /* optional */ false)));
+      checkAndEat(TokenKind::comma, JSLexer::GrammarContext::Type);
+    } else if (optNext.hasValue() && *optNext == TokenKind::question) {
+      error(tok_->getSourceRange(), "'this' constraint may not be optional");
+      return None;
+    }
+  }
+
   if (allowAnonFunctionType_ &&
       checkAndEat(TokenKind::dotdotdot, JSLexer::GrammarContext::Type)) {
     isFunction = true;

diff --git a/lib/Parser/JSParserImpl.cpp b/lib/Parser/JSParserImpl.cpp
@@ -590,9 +590,9 @@ bool JSParserImpl::parseFormalParameters(
   // (
   SMLoc lparenLoc = advance().Start;
 
-#if HERMES_PARSE_FLOW
-  // The first parameter can be 'this' in Flow mode.
-  if (context_.getParseFlow() && check(TokenKind::rw_this)) {
+#if HERMES_PARSE_FLOW || HERMES_PARSE_TS
+  // The first parameter can be 'this' in Flow and TypeScript.
+  if (context_.getParseTypes() && check(TokenKind::rw_this)) {
     auto *name = tok_->getResWordIdentifier();
     SMLoc thisParamStart = advance().Start;
 
@@ -605,7 +605,7 @@ bool JSParserImpl::parseFormalParameters(
             thisParamStart))
       return false;
 
-    auto optType = parseTypeAnnotationFlow(annotStart);
+    auto optType = parseTypeAnnotation(annotStart);
     if (!optType)
       return false;
     ESTree::Node *type = *optType;

diff --git a/test/Parser/ts/function-alias.ts b/test/Parser/ts/function-alias.ts
@@ -291,6 +291,32 @@ type A = ({x}: number) => number;
 // CHECK-NEXT:         },
 // CHECK-NEXT:         "typeParameters": null
 // CHECK-NEXT:       }
+// CHECK-NEXT:     },
+
+type A = (this: string) => void;
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "type": "TSTypeAliasDeclaration",
+// CHECK-NEXT:       "id": {
+// CHECK-NEXT:         "type": "Identifier",
+// CHECK-NEXT:         "name": "A"
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "typeParameters": null,
+// CHECK-NEXT:       "typeAnnotation": {
+// CHECK-NEXT:         "type": "TSFunctionType",
+// CHECK-NEXT:         "params": [
+// CHECK-NEXT:           {
+// CHECK-NEXT:             "type": "Identifier",
+// CHECK-NEXT:             "name": "this",
+// CHECK-NEXT:             "typeAnnotation": {
+// CHECK-NEXT:               "type": "TSStringKeyword"
+// CHECK-NEXT:             }
+// CHECK-NEXT:           }
+// CHECK-NEXT:         ],
+// CHECK-NEXT:         "returnType": {
+// CHECK-NEXT:           "type": "TSVoidKeyword"
+// CHECK-NEXT:         },
+// CHECK-NEXT:         "typeParameters": null
+// CHECK-NEXT:       }
 // CHECK-NEXT:     }
 
 // CHECK-NEXT:   ]

diff --git a/test/Parser/ts/function-this-error.ts b/test/Parser/ts/function-this-error.ts
@@ -0,0 +1,13 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// RUN: (! %hermes -parse-ts -dump-ast -pretty-json %s 2>&1) | %FileCheck %s --match-full-lines
+
+type A = (this?: string) => void;
+// CHECK: {{.*}}:10:11: error: 'this' constraint may not be optional
+// CHECK-NEXT: type A = (this?: string) => void;
+// CHECK-NEXT:           ^~~~
diff --git a/test/Parser/ts/function.ts b/test/Parser/ts/function.ts
@@ -0,0 +1,85 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// RUN: %hermesc -parse-ts -dump-ast -pretty-json %s | %FileCheck %s --match-full-lines
+
+// CHECK-LABEL: {
+// CHECK-NEXT:   "type": "Program",
+// CHECK-NEXT:   "body": [
+
+function foo(this: string, x: boolean, y?: number, ...args: string[]): void {}
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "type": "FunctionDeclaration",
+// CHECK-NEXT:       "id": {
+// CHECK-NEXT:         "type": "Identifier",
+// CHECK-NEXT:         "name": "foo"
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "params": [
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "type": "Identifier",
+// CHECK-NEXT:           "name": "this",
+// CHECK-NEXT:           "typeAnnotation": {
+// CHECK-NEXT:             "type": "TSTypeAnnotation",
+// CHECK-NEXT:             "typeAnnotation": {
+// CHECK-NEXT:               "type": "TSStringKeyword"
+// CHECK-NEXT:             }
+// CHECK-NEXT:           }
+// CHECK-NEXT:         },
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "type": "Identifier",
+// CHECK-NEXT:           "name": "x",
+// CHECK-NEXT:           "typeAnnotation": {
+// CHECK-NEXT:             "type": "TSTypeAnnotation",
+// CHECK-NEXT:             "typeAnnotation": {
+// CHECK-NEXT:               "type": "TSBooleanKeyword"
+// CHECK-NEXT:             }
+// CHECK-NEXT:           }
+// CHECK-NEXT:         },
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "type": "Identifier",
+// CHECK-NEXT:           "name": "y",
+// CHECK-NEXT:           "typeAnnotation": {
+// CHECK-NEXT:             "type": "TSTypeAnnotation",
+// CHECK-NEXT:             "typeAnnotation": {
+// CHECK-NEXT:               "type": "TSNumberKeyword"
+// CHECK-NEXT:             }
+// CHECK-NEXT:           },
+// CHECK-NEXT:           "optional": true
+// CHECK-NEXT:         },
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "type": "RestElement",
+// CHECK-NEXT:           "argument": {
+// CHECK-NEXT:             "type": "Identifier",
+// CHECK-NEXT:             "name": "args",
+// CHECK-NEXT:             "typeAnnotation": {
+// CHECK-NEXT:               "type": "TSTypeAnnotation",
+// CHECK-NEXT:               "typeAnnotation": {
+// CHECK-NEXT:                 "type": "TSArrayType",
+// CHECK-NEXT:                 "elementType": {
+// CHECK-NEXT:                   "type": "TSStringKeyword"
+// CHECK-NEXT:                 }
+// CHECK-NEXT:               }
+// CHECK-NEXT:             }
+// CHECK-NEXT:           }
+// CHECK-NEXT:         }
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "body": {
+// CHECK-NEXT:         "type": "BlockStatement",
+// CHECK-NEXT:         "body": []
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "returnType": {
+// CHECK-NEXT:         "type": "TSTypeAnnotation",
+// CHECK-NEXT:         "typeAnnotation": {
+// CHECK-NEXT:           "type": "TSVoidKeyword"
+// CHECK-NEXT:         }
+// CHECK-NEXT:       },
+// CHECK-NEXT:       "generator": false,
+// CHECK-NEXT:       "async": false
+// CHECK-NEXT:     }
+
+// CHECK-NEXT:   ]
+// CHECK-NEXT: }