Avoid vanity alignment in long pattern match

Fixes https://github.com/fsprojects/fantomas/issues/1926 Co-authored-by: ijanus <[email protected]>
nblockchain · Apr 15, 2022 · 2a36ace · 2a36ace
1 parent a1e4e4b
commit 2a36ace
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Showing 2 changed files with 61 additions and 7 deletions.
diff --git a/src/Fantomas.Tests/PatternMatchingTests.fs b/src/Fantomas.Tests/PatternMatchingTests.fs
@@ -1217,8 +1217,10 @@ type Thing =
     | Foo of msg: string
     override this.ToString() =
         match this with
-        | Foo (ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff) ->
-            ""
+        | Foo
+            (
+                ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+            ) -> ""
 """
 
 [<Test>]
@@ -1248,8 +1250,10 @@ type Thing =
     | Foo of msg : string
     override this.ToString() : string =
         match this with
-        | Foo (ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff) ->
-            ""
+        | Foo
+            (
+                ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+            ) -> ""
 """
 
 [<Test>]
@@ -2165,6 +2169,37 @@ match! a with // foo
 | B b -> ()
 """
 
+[<Test>]
+let ``vanity alignment used when using long case in match block, 1926`` () =
+    formatSourceString
+        false
+        """
+match foo with
+| SomeVeryLongMatchCase(1234567890, 1234567890, 1234567890, 1234567890, 1234567890, 1234567890, 1234567890, 1234567890, 1234567890, 1234567890) ->
+    bar()
+| _ -> () """
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+match foo with
+| SomeVeryLongMatchCase
+    (
+        1234567890,
+        1234567890,
+        1234567890,
+        1234567890,
+        1234567890,
+        1234567890,
+        1234567890,
+        1234567890,
+        1234567890,
+        1234567890
+    ) -> bar ()
+| _ -> ()
+"""
+
 [<Test>]
 let ``comment after match keyword, 1851`` () =
     formatSourceString

diff --git a/src/Fantomas/CodePrinter.fs b/src/Fantomas/CodePrinter.fs
@@ -5026,9 +5026,28 @@ and genPat astContext pat =
 
     | PatParen (_, PatUnitConst, _) -> !- "()"
     | PatParen (lpr, p, rpr) ->
-        genTriviaFor SynPat_Paren_OpeningParenthesis lpr sepOpenT
-        +> genPat astContext p
-        +> genTriviaFor SynPat_Paren_ClosingParenthesis rpr sepCloseT
+        let shortExpr =
+            genTriviaFor SynPat_Paren_OpeningParenthesis lpr sepOpenT
+            +> genPat astContext p
+            +> genTriviaFor SynPat_Paren_ClosingParenthesis rpr sepCloseT
+
+        let longExpr =
+            ifElse
+                astContext.IsInsideMatchClausePattern
+                (indent
+                 +> sepNln
+                 +> genTriviaFor SynPat_Paren_OpeningParenthesis lpr sepOpenT
+                 +> sepNln
+                 +> (fun ctx -> (rep ctx.Config.IndentSize (!- " ")) ctx)
+                 +> genPat astContext p
+                 +> sepNln
+                 +> genTriviaFor SynPat_Paren_ClosingParenthesis rpr sepCloseT
+                 +> unindent)
+                (genTriviaFor SynPat_Paren_OpeningParenthesis lpr sepOpenT
+                 +> genPat astContext p
+                 +> genTriviaFor SynPat_Paren_ClosingParenthesis rpr sepCloseT)
+
+        expressionFitsOnRestOfLine shortExpr longExpr
     | PatTuple ps ->
         expressionFitsOnRestOfLine
             (col sepComma ps (genPat astContext))