From e52460a0a9145c0eb6804c9aa59a6ba98ba29dc0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Tue, 1 Feb 2022 18:10:37 +0100
Subject: [PATCH] Remove unreachable code

---
 .../babel-parser/src/parser/expression.js     | 24 +--------
 packages/babel-parser/src/tokenizer/index.js  | 49 +++++++++----------
 2 files changed, 25 insertions(+), 48 deletions(-)

diff --git a/packages/babel-parser/src/parser/expression.js b/packages/babel-parser/src/parser/expression.js
index f67d56160d64..2e0cf1a22b95 100644
--- a/packages/babel-parser/src/parser/expression.js
+++ b/packages/babel-parser/src/parser/expression.js
@@ -1204,29 +1204,7 @@ export default class ExpressionParser extends LValParser {
         return this.parseTopicReferenceThenEqualsSign(tt.bitwiseXOR, "^");
       }
 
-      case tt.doubleCaret: {
-        const pipeProposal = this.getPluginOption(
-          "pipelineOperator",
-          "proposal",
-        );
-        const pluginTopicToken = this.getPluginOption(
-          "pipelineOperator",
-          "topicToken",
-        );
-
-        // The `^^` token is valid only when:
-        // the pipe-operator proposal is active,
-        // its "pipeProposal" is configured as "hack",
-        // and "topicToken" is configured as "^^".
-        // If the pipe-operator proposal settles on a token that is not ^^,
-        // then this token type may be removed.
-        if (pipeProposal === "hack" && pluginTopicToken === "^^") {
-          return this.parseTopicReference(pipeProposal);
-        } else {
-          throw this.unexpected();
-        }
-      }
-
+      case tt.doubleCaret:
       case tt.doubleAt:
       case tt.bitwiseXOR:
       case tt.modulo:
diff --git a/packages/babel-parser/src/tokenizer/index.js b/packages/babel-parser/src/tokenizer/index.js
index 699a51691533..3fc7d58abfd9 100644
--- a/packages/babel-parser/src/tokenizer/index.js
+++ b/packages/babel-parser/src/tokenizer/index.js
@@ -715,10 +715,6 @@ export default class Tokenizer extends ParserErrors {
 
   readToken_caret(): void {
     const next = this.input.charCodeAt(this.state.pos + 1);
-    const pipeProposal = this.getPluginOption("pipelineOperator", "proposal");
-    const topicToken = this.getPluginOption("pipelineOperator", "topicToken");
-    const hackPipeWithDoubleCaretIsActive =
-      pipeProposal === "hack" && topicToken === "^^";
 
     // '^='
     if (next === charCodes.equalsTo && !this.state.inType) {
@@ -726,25 +722,28 @@ export default class Tokenizer extends ParserErrors {
       // If the proposal ends up choosing a different token,
       // it can be merged with tt.assign.
       this.finishOp(tt.xorAssign, 2);
+      return;
     }
+
     // '^^'
-    else if (hackPipeWithDoubleCaretIsActive && next === charCodes.caret) {
-      // `tt.doubleCaret` is only needed to support ^^
-      // as a Hack-pipe topic token.
-      // If the proposal ends up choosing a different token,
-      // it may be removed.
-      this.finishOp(tt.doubleCaret, 2);
+    if (next === charCodes.caret) {
+      const pipeProposal = this.getPluginOption("pipelineOperator", "proposal");
+      const topicToken = this.getPluginOption("pipelineOperator", "topicToken");
+      if (pipeProposal === "hack" && topicToken === "^^") {
+        this.finishOp(tt.doubleCaret, 2);
+
+        // `^^^` is forbidden and must be separated by a space.
+        const lookaheadCh = this.input.codePointAt(this.state.pos);
+        if (lookaheadCh === charCodes.caret) {
+          throw this.unexpected();
+        }
 
-      // `^^^` is forbidden and must be separated by a space.
-      const lookaheadCh = this.input.codePointAt(this.state.pos);
-      if (lookaheadCh === charCodes.caret) {
-        throw this.unexpected();
+        return;
       }
     }
+
     // '^'
-    else {
-      this.finishOp(tt.bitwiseXOR, 1);
-    }
+    this.finishOp(tt.bitwiseXOR, 1);
   }
 
   readToken_atSign(): void {
@@ -752,16 +751,16 @@ export default class Tokenizer extends ParserErrors {
 
     // '@@'
     if (next === charCodes.atSign) {
-      // `tt.doubleAt` is only needed to support @@
-      // as a Hack-pipe topic token.
-      // If the proposal ends up choosing a different token,
-      // it may be removed.
-      this.finishOp(tt.doubleAt, 2);
+      const pipeProposal = this.getPluginOption("pipelineOperator", "proposal");
+      const topicToken = this.getPluginOption("pipelineOperator", "topicToken");
+      if (pipeProposal === "hack" && topicToken === "@@") {
+        this.finishOp(tt.doubleAt, 2);
+        return;
+      }
     }
+
     // '@'
-    else {
-      this.finishOp(tt.at, 1);
-    }
+    this.finishOp(tt.at, 1);
   }
 
   readToken_plus_min(code: number): void {