fixes #13519

7 files changed, 37 insertions, 7 deletions

diff --git a/changelog.md b/changelog.md
index 44c654fd3..b76946464 100644
--- a/changelog.md
+++ b/changelog.md
@@ -40,6 +40,10 @@
 - The `{.dynlib.}` pragma is now required for exporting symbols when making
   shared objects on POSIX and macOS, which make it consistent with the behavior
   on Windows.
+- The compiler is now more strict about type conversions concerning proc
+  types: Type conversions cannot be used to hide `.raise` effects or side
+  effects, instead a `cast` must be used. With the flag `--useVersion:1.0` the
+  old behaviour is emulated.
 
 
 ## Library additions
diff --git a/compiler/ast.nim b/compiler/ast.nim
index b82002b06..62c301a43 100644
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@@ -592,8 +592,11 @@ const
   tfReturnsNew* = tfInheritable
   skError* = skUnknown
 
-  # type flags that are essential for type equality:
-  eqTypeFlags* = {tfIterator, tfNotNil, tfVarIsPtr}
+var
+  eqTypeFlags* = {tfIterator, tfNotNil, tfVarIsPtr, tfGcSafe, tfNoSideEffect}
+    ## type flags that are essential for type equality.
+    ## This is now a variable because for emulation of version:1.0 we
+    ## might exclude {tfGcSafe, tfNoSideEffect}.
 
 type
   TMagic* = enum # symbols that require compiler magic:
diff --git a/compiler/commands.nim b/compiler/commands.nim
index 935d7e2be..0c93654da 100644
--- a/compiler/commands.nim
+++ b/compiler/commands.nim
@@ -32,6 +32,7 @@ import
   pathutils, strtabs
 
 from incremental import nimIncremental
+from ast import eqTypeFlags, tfGcSafe, tfNoSideEffect
 
 # but some have deps to imported modules. Yay.
 bootSwitch(usedTinyC, hasTinyCBackend, "-d:tinyc")
@@ -869,10 +870,11 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
     of "1.0":
       defineSymbol(conf.symbols, "NimMajor", "1")
       defineSymbol(conf.symbols, "NimMinor", "0")
-      # always be compatible with 1.0.2 for now:
-      defineSymbol(conf.symbols, "NimPatch", "2")
+      # always be compatible with 1.0.100:
+      defineSymbol(conf.symbols, "NimPatch", "100")
       # old behaviors go here:
       defineSymbol(conf.symbols, "nimOldRelativePathBehavior")
+      ast.eqTypeFlags.excl {tfGcSafe, tfNoSideEffect}
     else:
       localError(conf, info, "unknown Nim version; currently supported values are: {1.0}")
   of "benchmarkvm":
diff --git a/lib/pure/asyncdispatch.nim b/lib/pure/asyncdispatch.nim
index d724242d7..732381ccb 100644
--- a/lib/pure/asyncdispatch.nim
+++ b/lib/pure/asyncdispatch.nim
@@ -278,7 +278,7 @@ when defined(windows) or defined(nimdoc):
     result.ioPort = createIoCompletionPort(INVALID_HANDLE_VALUE, 0, 0, 1)
     result.handles = initSet[AsyncFD]()
     result.timers.newHeapQueue()
-    result.callbacks = initDeque[proc ()](64)
+    result.callbacks = initDeque[proc () {.closure, gcsafe.}](64)
 
   var gDisp{.threadvar.}: owned PDispatcher ## Global dispatcher
 
diff --git a/lib/pure/asyncmacro.nim b/lib/pure/asyncmacro.nim
index 11eba427b..ce84491eb 100644
--- a/lib/pure/asyncmacro.nim
+++ b/lib/pure/asyncmacro.nim
@@ -46,7 +46,7 @@ template createCb(retFutureSym, iteratorNameSym,
         else:
           {.gcsafe.}:
             {.push hint[ConvFromXtoItselfNotNeeded]: off.}
-            next.callback = (proc() {.closure, gcsafe.})(identName)
+            next.callback = cast[proc() {.closure, gcsafe.}](identName)
             {.pop.}
     except:
       futureVarCompletions
diff --git a/lib/system/assertions.nim b/lib/system/assertions.nim
index b918729dc..5eb700f4c 100644
--- a/lib/system/assertions.nim
+++ b/lib/system/assertions.nim
@@ -26,7 +26,7 @@ proc failedAssertImpl*(msg: string) {.raises: [], tags: [].} =
   # by ``assert``.
   type Hide = proc (msg: string) {.noinline, raises: [], noSideEffect,
                                     tags: [].}
-  Hide(raiseAssert)(msg)
+  cast[Hide](raiseAssert)(msg)
 
 template assertImpl(cond: bool, msg: string, expr: string, enabled: static[bool]) =
   when enabled:
diff --git a/tests/generics/tarc_misc.nim b/tests/generics/tarc_misc.nim
new file mode 100644
index 000000000..3e7762556
--- /dev/null
+++ b/tests/generics/tarc_misc.nim
@@ -0,0 +1,21 @@
+discard """
+  output: ''''''
+  cmd: "nim c --gc:arc $file"
+"""
+
+# bug #13519
+
+var unrelated: seq[proc() {.closure, gcsafe.}]
+
+unrelated.add proc () =
+  echo "gcsafe"
+
+import tables, sequtils
+let t = newTable[int, proc()]()
+
+type
+  MyProc = proc() {.closure.}
+
+var result: seq[MyProc] = @[]
+for x in t.values:
+  result.add(x)