group a leftover right operand in case it's a single binary operation next to an AssignmentExpression (#1161)

Author: Janther

src/binary-operator-printers/printers/create-binary-operation-printer.js

@@ -10,7 +10,7 @@ const rightOperandPrinter = (node, path, print) => {
   // operand like - 1 on its own line
   const parent = path.getParentNode();
   return node.left.type !== 'BinaryOperation' &&
-    parent.type !== 'BinaryOperation'
+    (parent.type !== 'BinaryOperation' || assignment.match(parent.operator))
     ? group(right)
     : right;
 };

src/slang-printers/create-binary-operation-printer.ts

@@ -1,4 +1,4 @@
-import { TerminalKind } from '@nomicfoundation/slang/cst';
+import { NonterminalKind, TerminalKind } from '@nomicfoundation/slang/cst';
 import { doc } from 'prettier';
 import { isBinaryOperation } from '../slang-utils/is-binary-operation.js';
 
@@ -24,11 +24,15 @@ function rightOperandPrint(
   ];
   // If it's a single binary operation, avoid having a small right
   // operand like - 1 on its own line
+  const leftOperand = node.leftOperand.variant;
+  const grandparentNode = path.getNode(2) as StrictAstNode;
   const shouldGroup =
     !(
-      node.leftOperand.variant.kind !== TerminalKind.Identifier &&
-      isBinaryOperation(node.leftOperand.variant)
-    ) && !isBinaryOperation(path.getNode(2) as StrictAstNode);
+      leftOperand.kind !== TerminalKind.Identifier &&
+      isBinaryOperation(leftOperand)
+    ) &&
+    (!isBinaryOperation(grandparentNode) ||
+      grandparentNode.kind === NonterminalKind.AssignmentExpression);
 
   return shouldGroup ? group(rightOperand) : rightOperand;
 }

tests/format/BinaryOperators/__snapshots__/format.test.js.snap

@@ -264,8 +264,7 @@ contract ArithmeticOperators {
         a =
             veryVeryVeryVeryVeryLongFunctionCalledA(
                 veryVeryVeryVeryVeryLongVariableCalledB
-            ) +
-            c;
+            ) + c;
         if (
             veryVeryVeryVeryVeryLongFunctionCalledA(
                 veryVeryVeryVeryVeryLongVariableCalledB
@@ -353,8 +352,7 @@ contract ArithmeticOperators {
         a =
             veryVeryVeryVeryVeryLongFunctionCalledA(
                 veryVeryVeryVeryVeryLongVariableCalledB
-            ) **
-            c;
+            ) ** c;
         if (
             veryVeryVeryVeryVeryLongFunctionCalledA(
                 veryVeryVeryVeryVeryLongVariableCalledB
@@ -509,8 +507,7 @@ contract ComparisonOperators {
         a =
             veryVeryVeryVeryVeryLongFunctionCalledA(
                 veryVeryVeryVeryVeryLongVariableCalledB
-            ) ==
-            c;
+            ) == c;
         if (
             veryVeryVeryVeryVeryLongFunctionCalledA(
                 veryVeryVeryVeryVeryLongVariableCalledB
@@ -663,8 +660,7 @@ contract LogicalOperators {
         a =
             veryVeryVeryVeryVeryLongFunctionCalledA(
                 veryVeryVeryVeryVeryLongVariableCalledB
-            ) ||
-            c;
+            ) || c;
         if (
             veryVeryVeryVeryVeryLongFunctionCalledA(
                 veryVeryVeryVeryVeryLongVariableCalledB

tests/format/strings/__snapshots__/format.test.js.snap

@@ -1475,8 +1475,7 @@ library strings {
                     ptr,
                     needle._len,
                     needle._ptr
-                ) +
-                needle._len;
+                ) + needle._len;
         }
     }