From a90452142e1e4d28a4ea5701747382f98f3e245e Mon Sep 17 00:00:00 2001
From: Don Syme <dsyme@users.noreply.github.com>
Date: Wed, 20 Apr 2022 15:56:40 +1000
Subject: [PATCH 1/2] try to fix analysis of conjunctive patterns

---
 src/fsharp/PatternMatchCompilation.fs | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/src/fsharp/PatternMatchCompilation.fs b/src/fsharp/PatternMatchCompilation.fs
index 94d930751f6..387b39c8cf9 100644
--- a/src/fsharp/PatternMatchCompilation.fs
+++ b/src/fsharp/PatternMatchCompilation.fs
@@ -143,7 +143,6 @@ let GetSubExprOfInput g (gtps, tyargs, tinst) (SubExpr(accessf, (ve2, v2))) =
 // The ints record which choices taken, e.g. tuple/record fields.
 type Path =
     | PathQuery of Path * Unique
-    | PathConj of Path * int
     | PathTuple of Path * TypeInst * int
     | PathRecd of Path * TyconRef * TypeInst * int
     | PathUnionConstr of Path * UnionCaseRef * TypeInst * int
@@ -154,7 +153,6 @@ type Path =
 let rec pathEq p1 p2 =
     match p1, p2 with
     | PathQuery(p1, n1), PathQuery(p2, n2) -> (n1 = n2) && pathEq p1 p2
-    | PathConj(p1, n1), PathConj(p2, n2) -> (n1 = n2) && pathEq p1 p2
     | PathTuple(p1, _, n1), PathTuple(p2, _, n2) -> (n1 = n2) && pathEq p1 p2
     | PathRecd(p1, _, _, n1), PathRecd(p2, _, _, n2) -> (n1 = n2) && pathEq p1 p2
     | PathUnionConstr(p1, _, _, n1), PathUnionConstr(p2, _, _, n2) -> (n1 = n2) && pathEq p1 p2
@@ -203,8 +201,6 @@ let RefuteDiscrimSet g m path discrims =
     let rec go path tm =
         match path with
         | PathQuery _ -> raise CannotRefute
-        | PathConj (p, _j) ->
-            go p tm
         | PathTuple (p, tys, j) ->
             let k, eCoversVals = mkOneKnown tm j tys
             go p (fun _ -> mkRefTupled g m k tys, eCoversVals)
@@ -393,8 +389,6 @@ type Frontier = Frontier of ClauseNumber * Actives * ValMap<Expr>
 type InvestigationPoint = Investigation of ClauseNumber * DecisionTreeTest * Path
 
 // Note: actives must be a SortedDictionary
-// REVIEW: improve these data structures, though surprisingly these functions don't tend to show up
-// on profiling runs
 let rec isMemOfActives p1 actives =
     match actives with
     | [] -> false
@@ -1611,7 +1605,7 @@ let CompilePatternBasic
             subPats |> List.collect (fun subPat -> BindProjectionPattern (Active(inpPath, inpExpr, subPat)) activeState)
 
         | TPat_conjs(subPats, _m) ->
-            let newActives = List.mapi (mkSubActive (fun path j -> PathConj(path, j)) (fun _j -> inpAccess)) subPats
+            let newActives = List.mapi (mkSubActive (fun path _j -> path) (fun _j -> inpAccess)) subPats
             BindProjectionPatterns newActives activeState
 
         | TPat_range (c1, c2, m) ->

From 27c38ca36fbcea8b6613b6e08069ab184225faf3 Mon Sep 17 00:00:00 2001
From: Don Syme <dsyme@users.noreply.github.com>
Date: Thu, 22 Sep 2022 15:54:52 +0100
Subject: [PATCH 2/2] add test cases

---
 tests/fsharp/tests.fs                  | 15 +++++++++++++++
 tests/fsharp/typecheck/sigs/pos1281.fs | 17 +++++++++++++++++
 tests/fsharp/typecheck/sigs/pos3294.fs |  8 ++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 tests/fsharp/typecheck/sigs/pos1281.fs
 create mode 100644 tests/fsharp/typecheck/sigs/pos3294.fs

diff --git a/tests/fsharp/tests.fs b/tests/fsharp/tests.fs
index c40d9f756e6..97575c2f6b5 100644
--- a/tests/fsharp/tests.fs
+++ b/tests/fsharp/tests.fs
@@ -2583,6 +2583,21 @@ module TypecheckTests =
         peverify cfg "pos40.exe"
         exec cfg ("." ++ "pos40.exe") ""
 
+    [<Test>]
+    let ``sigs pos1281`` () =
+        let cfg = testConfig "typecheck/sigs"
+        // This checks that warning 25 "incomplete matches" is not triggered
+        fsc cfg "%s --target:exe -o:pos1281.exe --warnaserror --nowarn:26" cfg.fsc_flags ["pos1281.fs"]
+        peverify cfg "pos1281.exe"
+        exec cfg ("." ++ "pos1281.exe") ""
+
+    [<Test>]
+    let ``sigs pos3294`` () =
+        let cfg = testConfig "typecheck/sigs"
+        fsc cfg "%s --target:exe -o:pos3294.exe --warnaserror" cfg.fsc_flags ["pos3294.fs"]
+        peverify cfg "pos3294.exe"
+        exec cfg ("." ++ "pos3294.exe") ""
+
     [<Test>]
     let ``sigs pos23`` () =
         let cfg = testConfig "typecheck/sigs"
diff --git a/tests/fsharp/typecheck/sigs/pos1281.fs b/tests/fsharp/typecheck/sigs/pos1281.fs
new file mode 100644
index 00000000000..f2a73c07c3d
--- /dev/null
+++ b/tests/fsharp/typecheck/sigs/pos1281.fs
@@ -0,0 +1,17 @@
+module Pos1281
+
+type Cond = Foo | Bar | Baz
+let (|SetV|) x _ = x
+
+let c = Cond.Foo
+
+match c with
+| Baz -> 
+    printfn "Baz"
+| Foo & SetV "and" kwd
+| Bar & SetV "or" kwd ->
+    printfn "Keyword: %s" kwd
+| Baz -> failwith "wat"
+
+printfn "test completed"
+exit 0
diff --git a/tests/fsharp/typecheck/sigs/pos3294.fs b/tests/fsharp/typecheck/sigs/pos3294.fs
new file mode 100644
index 00000000000..55fc5f2631b
--- /dev/null
+++ b/tests/fsharp/typecheck/sigs/pos3294.fs
@@ -0,0 +1,8 @@
+module Pos40
+
+let f = function
+    | [] -> 0
+    | (_ :: _) & _ -> 0
+
+printfn "test completed"
+exit 0