From 7168c3d933e3a9e0d23c366a78000540ca910411 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Sun, 24 Oct 2021 17:40:16 +0200
Subject: [PATCH] Review

---
 .../src/convert/convertTokens.cjs             | 30 +++---
 eslint/babel-eslint-parser/test/index.js      | 97 ++++++++++++++++++-
 yarn.lock                                     |  2 +-
 3 files changed, 114 insertions(+), 15 deletions(-)

diff --git a/eslint/babel-eslint-parser/src/convert/convertTokens.cjs b/eslint/babel-eslint-parser/src/convert/convertTokens.cjs
index c69f85b0c5e9..a05a0a09824a 100644
--- a/eslint/babel-eslint-parser/src/convert/convertTokens.cjs
+++ b/eslint/babel-eslint-parser/src/convert/convertTokens.cjs
@@ -200,23 +200,31 @@ module.exports = function convertTokens(tokens, code, tl) {
   const withoutComments = convertTemplateType(tokens, tl).filter(
     t => t.type !== "CommentLine" && t.type !== "CommentBlock",
   );
-  for (let i = 0; i < withoutComments.length; i++) {
-    let token = withoutComments[i];
+  for (let i = 0, { length } = withoutComments; i < length; i++) {
+    const token = withoutComments[i];
 
     if (!process.env.BABEL_8_BREAKING) {
       // Babel 8 already produces a single token
 
-      if (ESLINT_VERSION >= 8 && token.type.label === tl.hash) {
-        i++;
-        token = withoutComments[i];
+      if (
+        ESLINT_VERSION >= 8 &&
+        i + 1 < length &&
+        token.type.label === tl.hash
+      ) {
+        const nextToken = withoutComments[i + 1];
 
-        token.type = "PrivateIdentifier";
-        token.start -= 1;
-        token.loc.start.column -= 1;
-        token.range = [token.start, token.end];
+        // We must disambiguate private identifier from the hack pipes topic token
+        if (nextToken.type.label === tl.name && token.end === nextToken.start) {
+          i++;
 
-        result.push(token);
-        continue;
+          nextToken.type = "PrivateIdentifier";
+          nextToken.start -= 1;
+          nextToken.loc.start.column -= 1;
+          nextToken.range = [nextToken.start, nextToken.end];
+
+          result.push(nextToken);
+          continue;
+        }
       }
     }
 
diff --git a/eslint/babel-eslint-parser/test/index.js b/eslint/babel-eslint-parser/test/index.js
index b420a5f47fc6..16af7ccafa9f 100644
--- a/eslint/babel-eslint-parser/test/index.js
+++ b/eslint/babel-eslint-parser/test/index.js
@@ -423,7 +423,7 @@ describe("Babel and Espree", () => {
   });
 
   if (process.env.BABEL_8_BREAKING) {
-    it("hash (token) - ESLint 7", () => {
+    it("private identifier (token) - ESLint 7", () => {
       const code = "class A { #x }";
       const babylonAST = parseForESLint(code, {
         eslintVisitorKeys: true,
@@ -434,7 +434,6 @@ describe("Babel and Espree", () => {
       expect(babylonAST.tokens[3].value).toEqual("x");
     });
   } else {
-    // Espree doesn't support private fields yet
     it("hash (token) - ESLint 7", () => {
       const code = "class A { #x }";
       const babylonAST = parseForESLint(code, {
@@ -447,7 +446,7 @@ describe("Babel and Espree", () => {
     });
   }
 
-  it("hash (token) - ESLint 8", () => {
+  it("private identifier (token) - ESLint 8", () => {
     const code = "class A { #x }";
     const babylonAST = parseForESLint8(code, {
       eslintVisitorKeys: true,
@@ -576,6 +575,98 @@ describe("Babel and Espree", () => {
     expect(babylonAST.tokens[22]).toMatchObject(staticKw);
   });
 
+  if (process.env.BABEL_8_BREAKING) {
+    it("pipeline # topic token - ESLint 7", () => {
+      const code = `
+        x |> #
+        y |> #[0]
+        class A {
+          #x = y |>
+          #
+          z
+        }
+      `;
+      const babylonAST = parseForESLint(code, {
+        eslintVisitorKeys: true,
+        eslintScopeManager: true,
+        babelOptions: {
+          filename: "test.js",
+          parserOpts: {
+            plugins: [
+              ["pipelineOperator", { proposal: "hack", topicToken: "#" }],
+            ],
+            tokens: true,
+          },
+        },
+      }).ast;
+
+      const topicToken = { type: "Punctuator", value: "#" };
+      expect(babylonAST.tokens[2]).toMatchObject(topicToken);
+      expect(babylonAST.tokens[5]).toMatchObject(topicToken);
+      expect(babylonAST.tokens[16]).toMatchObject(topicToken);
+    });
+  } else {
+    it("pipeline # topic token - ESLint 7", () => {
+      const code = `
+        x |> #
+        y |> #[0]
+        class A {
+          #x = y |>
+          #
+          z
+        }
+      `;
+      const babylonAST = parseForESLint(code, {
+        eslintVisitorKeys: true,
+        eslintScopeManager: true,
+        babelOptions: {
+          filename: "test.js",
+          parserOpts: {
+            plugins: [
+              ["pipelineOperator", { proposal: "hack", topicToken: "#" }],
+            ],
+            tokens: true,
+          },
+        },
+      }).ast;
+
+      const topicToken = { type: "Punctuator", value: "#" };
+      expect(babylonAST.tokens[2]).toMatchObject(topicToken);
+      expect(babylonAST.tokens[5]).toMatchObject(topicToken);
+      expect(babylonAST.tokens[17]).toMatchObject(topicToken);
+    });
+  }
+
+  it("pipeline # topic token - ESLint 8", () => {
+    const code = `
+      x |> #
+      y |> #[0]
+      class A {
+        #x = y |>
+        #
+        z
+      }
+    `;
+    const babylonAST = parseForESLint8(code, {
+      eslintVisitorKeys: true,
+      eslintScopeManager: true,
+      babelOptions: {
+        filename: "test.js",
+        parserOpts: {
+          plugins: [
+            ["pipelineOperator", { proposal: "hack", topicToken: "#" }],
+          ],
+          tokens: true,
+        },
+      },
+    }).ast;
+
+    const topicToken = { type: "Punctuator", value: "#" };
+    expect(babylonAST.tokens[2]).toMatchObject(topicToken);
+    expect(babylonAST.tokens[5]).toMatchObject(topicToken);
+    expect(babylonAST.tokens[16]).toMatchObject(topicToken);
+  });
+
   it("empty program with line comment", () => {
     parseAndAssertSame("// single comment");
   });
diff --git a/yarn.lock b/yarn.lock
index 0d20e53b7975..0da6bc09f86d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7723,7 +7723,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"eslint-8@npm:eslint@^8.0.0, eslint@npm:8.0.0":
+"eslint-8@npm:eslint@^8.0.0":
   version: 8.0.0
   resolution: "eslint@npm:8.0.0"
   dependencies: