From 08afa030756cd3209520f6db596605116bc246ac Mon Sep 17 00:00:00 2001
From: Zahary Karadjov <zahary@gmail.com>
Date: Wed, 1 Apr 2020 04:01:25 +0300
Subject: [PATCH] The raises list can now use expressions referencing the
 generic params

---
 compiler/pragmas.nim  | 11 +++++++----
 compiler/sem.nim      |  1 +
 compiler/semdata.nim  |  2 ++
 compiler/sempass2.nim |  7 ++++++-
 4 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/compiler/pragmas.nim b/compiler/pragmas.nim
index 100ce15602..6816a1705d 100644
--- a/compiler/pragmas.nim
+++ b/compiler/pragmas.nim
@@ -637,10 +637,13 @@ proc processPragma(c: PContext, n: PNode, i: int) =
 
 proc pragmaRaisesOrTags(c: PContext, n: PNode) =
   proc processExc(c: PContext, x: PNode) =
-    var t = skipTypes(c.semTypeNode(c, x, nil), skipPtrs)
-    if t.kind != tyObject:
-      localError(c.config, x.info, errGenerated, "invalid type for raises/tags list")
-    x.typ = t
+    if c.hasUnresolvedArgs(c, x):
+      x.typ = makeTypeFromExpr(c, x)
+    else:
+      var t = skipTypes(c.semTypeNode(c, x, nil), skipPtrs)
+      if t.kind != tyObject and not t.isMetaType:
+        localError(c.config, x.info, errGenerated, "invalid type for raises/tags list")
+      x.typ = t
 
   if n.kind in nkPragmaCallKinds and n.len == 2:
     let it = n[1]
diff --git a/compiler/sem.nim b/compiler/sem.nim
index 471a300995..1ced234f57 100644
--- a/compiler/sem.nim
+++ b/compiler/sem.nim
@@ -521,6 +521,7 @@ proc myOpen(graph: ModuleGraph; module: PSym): PPassContext =
   c.semGenerateInstance = generateInstance
   c.semTypeNode = semTypeNode
   c.instTypeBoundOp = sigmatch.instTypeBoundOp
+  c.hasUnresolvedArgs = hasUnresolvedArgs
 
   pushProcCon(c, module)
   pushOwner(c, c.module)
diff --git a/compiler/semdata.nim b/compiler/semdata.nim
index fbc9762f3b..7ec4c423f9 100644
--- a/compiler/semdata.nim
+++ b/compiler/semdata.nim
@@ -104,6 +104,8 @@ type
     semTryExpr*: proc (c: PContext, n: PNode, flags: TExprFlags = {}): PNode {.nimcall.}
     semTryConstExpr*: proc (c: PContext, n: PNode): PNode {.nimcall.}
     computeRequiresInit*: proc (c: PContext, t: PType): bool {.nimcall.}
+    hasUnresolvedArgs*: proc (c: PContext, n: PNode): bool
+
     semOperand*: proc (c: PContext, n: PNode, flags: TExprFlags = {}): PNode {.nimcall.}
     semConstBoolExpr*: proc (c: PContext, n: PNode): PNode {.nimcall.} # XXX bite the bullet
     semOverloadedCall*: proc (c: PContext, n, nOrig: PNode,
diff --git a/compiler/sempass2.nim b/compiler/sempass2.nim
index a4e1dcf007..86149330e5 100644
--- a/compiler/sempass2.nim
+++ b/compiler/sempass2.nim
@@ -1083,7 +1083,12 @@ proc track(tracked: PEffects, n: PNode) =
     for i in 0..<n.safeLen: track(tracked, n[i])
 
 proc subtypeRelation(g: ModuleGraph; spec, real: PNode): bool =
-  result = safeInheritanceDiff(g.excType(real), spec.typ) <= 0
+  if spec.typ.kind == tyOr:
+    for t in spec.typ.sons:
+      if safeInheritanceDiff(g.excType(real), t) <= 0:
+        return true
+  else:
+    return safeInheritanceDiff(g.excType(real), spec.typ) <= 0
 
 proc checkRaisesSpec(g: ModuleGraph; spec, real: PNode, msg: string, hints: bool;
                      effectPredicate: proc (g: ModuleGraph; a, b: PNode): bool {.nimcall.}) =