diff --git a/compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala b/compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala
index 6c6348e80a03..243499d382e9 100644
--- a/compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala
+++ b/compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala
@@ -54,7 +54,7 @@ object SyntaxHighlighting {
     @forceInline def keywordStart =
       prev == 0    || prev == ' ' || prev == '{' || prev == '(' ||
       prev == '\n' || prev == '[' || prev == ',' || prev == ':' ||
-      prev == '|'  || prev == '&'
+      prev == '|'  || prev == '&' || prev.isDigit
 
     @forceInline def numberStart(c: Char) =
       c.isDigit && (!prev.isLetter || prev == '.' || prev == ' ' || prev == '(' || prev == '\u0000')
diff --git a/compiler/test/dotty/tools/dotc/printing/SyntaxHighlightingTests.scala b/compiler/test/dotty/tools/dotc/printing/SyntaxHighlightingTests.scala
index 2b8d66d84424..d02fd1d0b4cd 100644
--- a/compiler/test/dotty/tools/dotc/printing/SyntaxHighlightingTests.scala
+++ b/compiler/test/dotty/tools/dotc/printing/SyntaxHighlightingTests.scala
@@ -64,6 +64,7 @@ class SyntaxHighlightingTests {
   @Test
   def expressions = {
     test("val x = 1 + 2 + 3", "<K|val> <V|x> = <L|1> + <L|2> + <L|3>")
+    test("if (true) 3 else 1", "<K|if> (<K|true>) <L|3> <K|else> <L|1>")
   }
 
   @Test