Cache contextual type for || operator to avoid exponential compile time

ahejlsberg · ahejlsberg · commit effa2597fa89 · 2017-08-30T16:22:16.000-07:00
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -13059,7 +13059,7 @@ namespace ts {
                 // expression has no contextual type, the right operand is contextually typed by the type of the left operand.
                 let type = getContextualType(binaryExpression);
                 if (!type && node === binaryExpression.right) {
-                    type = getTypeOfExpression(binaryExpression.left);
+                    type = getTypeOfExpression(binaryExpression.left, /*cache*/ true);
                 }
                 return type;
             }

Original file line number	Diff line number	Diff line change
`@@ -13059,7 +13059,7 @@ namespace ts {`
`13059`	`13059`	`// expression has no contextual type, the right operand is contextually typed by the type of the left operand.`
`13060`	`13060`	`let type = getContextualType(binaryExpression);`
`13061`	`13061`	`if (!type && node === binaryExpression.right) {`
`13062`		`- type = getTypeOfExpression(binaryExpression.left);`
	`13062`	`+ type = getTypeOfExpression(binaryExpression.left, /cache/ true);`
`13063`	`13063`	`}`
`13064`	`13064`	`return type;`
`13065`	`13065`	`}`