diff --git a/src/cmd/compile/internal/syntax/pos.go b/src/cmd/compile/internal/syntax/pos.go
index b5e53d268b..dd25d4f249 100644
--- a/src/cmd/compile/internal/syntax/pos.go
+++ b/src/cmd/compile/internal/syntax/pos.go
@@ -8,6 +8,8 @@ import "fmt"
 
 // PosMax is the largest line or column value that can be represented without loss.
 // Incoming values (arguments) larger than PosMax will be set to PosMax.
+//
+// Keep this consistent with maxLineCol in go/scanner.
 const PosMax = 1 << 30
 
 // A Pos represents an absolute (line, col) source position
diff --git a/src/go/scanner/scanner.go b/src/go/scanner/scanner.go
index 0cd9f5901d..75f835d310 100644
--- a/src/go/scanner/scanner.go
+++ b/src/go/scanner/scanner.go
@@ -255,7 +255,8 @@ func (s *Scanner) updateLineInfo(next, offs int, text []byte) {
 
 	// Put a cap on the maximum size of line and column numbers.
 	// 30 bits allows for some additional space before wrapping an int32.
-	const maxLineCol = 1<<30 - 1
+	// Keep this consistent with cmd/compile/internal/syntax.PosMax.
+	const maxLineCol = 1 << 30
 	var line, col int
 	i2, n2, ok2 := trailingDigits(text[:i-1])
 	if ok2 {