From a5342e4d319c80cafbdae975af57cbba53cbd7b3 Mon Sep 17 00:00:00 2001
From: Simon Jakobi <simon.jakobi@gmail.com>
Date: Fri, 5 Dec 2025 11:18:17 +0100
Subject: [PATCH 1/2] Add performance test for #205

When the timeout limit is raised, the test finishes after ~8s on my
laptop.
---
 prettyprinter/test/Testsuite/Main.hs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/prettyprinter/test/Testsuite/Main.hs b/prettyprinter/test/Testsuite/Main.hs
index 956dc829..6b18f400 100644
--- a/prettyprinter/test/Testsuite/Main.hs
+++ b/prettyprinter/test/Testsuite/Main.hs
@@ -53,6 +53,8 @@ tests = testGroup "Tests"
                    groupingPerformance
         , testCase "fillSep performance"
                    fillSepPerformance
+        , testCase "Issue 205"
+                   issue205
         ]
     , testGroup "Regression tests"
         [ testCase "layoutSmart: softline behaves like a newline (#49)"
@@ -285,6 +287,14 @@ fillSepPerformance = docPerformanceTest (pathological 1000)
     pathological :: Int -> Doc ann
     pathological n = iterate (\x -> fillSep ["a", x <+> "b"] ) "foobar" !! n
 
+issue205 :: Assertion
+issue205 = do
+    let doc = fillSep (replicate 30 (sep ["abc", "xyz" :: Doc ()]))
+        t = renderStrict (layoutSmart defaultLayoutOptions doc)
+    timeout 1000000 (evaluate t) >>= \t' -> case t' of
+      Nothing -> assertFailure "Timeout!"
+      Just _success -> pure ()
+
 regressionLayoutSmartSoftline :: Assertion
 regressionLayoutSmartSoftline
   = let doc = "a" <> softline <> "b"

From 8cb05e34c4139c7d2ad47cc54fd4bc5bfcb8c19a Mon Sep 17 00:00:00 2001
From: Simon Jakobi <simon.jakobi@gmail.com>
Date: Fri, 5 Dec 2025 11:34:15 +0100
Subject: [PATCH 2/2] Revert "layoutWL: Don't let indentation result in
 trailing whitespace (#139)"

This reverts commit 9635a5d694b934e8cac6abe158614ac17a8a89b8.

Fixes #205.
---
 prettyprinter/src/Prettyprinter/Internal.hs | 10 +---------
 prettyprinter/test/Testsuite/Main.hs        | 10 ----------
 2 files changed, 1 insertion(+), 19 deletions(-)

diff --git a/prettyprinter/src/Prettyprinter/Internal.hs b/prettyprinter/src/Prettyprinter/Internal.hs
index 25cd6afe..596742cf 100755
--- a/prettyprinter/src/Prettyprinter/Internal.hs
+++ b/prettyprinter/src/Prettyprinter/Internal.hs
@@ -2073,15 +2073,7 @@ layoutWadlerLeijen
         Empty           -> best nl cc ds
         Char c          -> let !cc' = cc+1 in SChar c (best nl cc' ds)
         Text l t        -> let !cc' = cc+l in SText l t (best nl cc' ds)
-        Line            -> let x = best i i ds
-                               -- Don't produce indentation if there's no
-                               -- following text on the same line.
-                               -- This prevents trailing whitespace.
-                               i' = case x of
-                                   SEmpty  -> 0
-                                   SLine{} -> 0
-                                   _       -> i
-                           in SLine i' x
+        Line            -> SLine i (best i i ds)
         FlatAlt x _     -> best nl cc (Cons i x ds)
         Cat x y         -> best nl cc (Cons i x (Cons i y ds))
         Nest j x        -> let !ij = i+j in best nl cc (Cons ij x ds)
diff --git a/prettyprinter/test/Testsuite/Main.hs b/prettyprinter/test/Testsuite/Main.hs
index 6b18f400..7af3f815 100644
--- a/prettyprinter/test/Testsuite/Main.hs
+++ b/prettyprinter/test/Testsuite/Main.hs
@@ -90,8 +90,6 @@ tests = testGroup "Tests"
             [ testCase "Line" regressionUnboundedGroupedLine
             , testCase "Line within align" regressionUnboundedGroupedLineWithinAlign
             ]
-        , testCase "Indentation on otherwise empty lines results in trailing whitespace (#139)"
-                   indentationShouldntCauseTrailingWhitespaceOnOtherwiseEmptyLines
         , testCase "Ribbon width should be computed with `floor` instead of `round` (#157)"
                    computeRibbonWidthWithFloor
         ]
@@ -395,14 +393,6 @@ regressionUnboundedGroupedLineWithinAlign
         expected = SChar 'x' (SLine 0 (SChar 'y' SEmpty))
     in assertEqual "" expected sdoc
 
-indentationShouldntCauseTrailingWhitespaceOnOtherwiseEmptyLines :: Assertion
-indentationShouldntCauseTrailingWhitespaceOnOtherwiseEmptyLines
-  = let doc :: Doc ()
-        doc = indent 1 ("x" <> hardline <> hardline <> "y" <> hardline)
-        sdoc = layoutPretty (LayoutOptions Unbounded) doc
-        expected = SChar ' ' (SChar 'x' (SLine 0 (SLine 1 (SChar 'y' (SLine 0 SEmpty)))))
-    in assertEqual "" expected sdoc
-
 computeRibbonWidthWithFloor :: Assertion
 computeRibbonWidthWithFloor
   = let doc :: Doc ()