1 files changed, 26 insertions, 5 deletions
diff --git a/compiler/semtypinst.nim b/compiler/semtypinst.nim
index 483db0bbb..759e8e6ab 100644
--- a/compiler/semtypinst.nim
+++ b/compiler/semtypinst.nim
@@ -118,7 +118,12 @@ proc replaceTypeVarsT*(cl: var TReplTypeVars, t: PType): PType =
   result = replaceTypeVarsTAux(cl, t)
   checkMetaInvariants(cl, result)
 
-proc prepareNode(cl: var TReplTypeVars, n: PNode): PNode =
+proc prepareNode*(cl: var TReplTypeVars, n: PNode): PNode =
+  ## instantiates a given generic expression, not a type node
+  if n.kind == nkSym and n.sym.kind == skType and
+      n.sym.typ != nil and n.sym.typ.kind == tyGenericBody:
+    # generic body types are allowed as user expressions, see #24090
+    return n
   let t = replaceTypeVarsT(cl, n.typ)
   if t != nil and t.kind == tyStatic and t.n != nil:
     return if tfUnresolved in t.flags: prepareNode(cl, t.n)
@@ -147,10 +152,14 @@ proc prepareNode(cl: var TReplTypeVars, n: PNode): PNode =
     # exception exists for the call name being a dot expression since
     # dot expressions need their LHS instantiated
     assert n.len != 0
-    let ignoreFirst = n[0].kind != nkDotExpr
+    # avoid instantiating generic proc symbols, refine condition if needed:
+    let ignoreFirst = n[0].kind notin {nkDotExpr, nkBracketExpr} + nkCallKinds
     let name = n[0].getPIdent
     let ignoreSecond = name != nil and name.s == "[]" and n.len > 1 and
-      (n[1].typ != nil and n[1].typ.kind == tyTypeDesc)
+      # generic type instantiation:
+      ((n[1].typ != nil and n[1].typ.kind == tyTypeDesc) or
+        # generic proc instantiation:
+        (n[1].kind == nkSym and n[1].sym.isGenericRoutineStrict))
     if ignoreFirst:
       result.add(n[0])
     else:
@@ -168,7 +177,10 @@ proc prepareNode(cl: var TReplTypeVars, n: PNode): PNode =
     # dot expressions need their LHS instantiated
     assert n.len != 0
     let ignoreFirst = n[0].kind != nkDotExpr and
-      n[0].typ != nil and n[0].typ.kind == tyTypeDesc
+      # generic type instantiation:
+      ((n[0].typ != nil and n[0].typ.kind == tyTypeDesc) or
+        # generic proc instantiation:
+        (n[0].kind == nkSym and n[0].sym.isGenericRoutineStrict))
     if ignoreFirst:
       result.add(n[0])
     else:
@@ -283,7 +295,8 @@ proc replaceTypeVarsN(cl: var TReplTypeVars, n: PNode; start=0; expectedType: PT
         replaceTypeVarsS(cl, n.sym, result.typ)
       else:
         replaceTypeVarsS(cl, n.sym, replaceTypeVarsT(cl, n.sym.typ))
-    if result.sym.typ.kind == tyVoid:
+    # sym type can be nil if was gensym created by macro, see #24048
+    if result.sym.typ != nil and result.sym.typ.kind == tyVoid:
       # don't add the 'void' field
       result = newNodeI(nkRecList, n.info)
   of nkRecWhen:
@@ -788,6 +801,14 @@ proc replaceTypesInBody*(p: PContext, pt: TypeMapping, n: PNode;
   result = replaceTypeVarsN(cl, n, expectedType = expectedType)
   popInfoContext(p.config)
 
+proc prepareTypesInBody*(p: PContext, pt: TypeMapping, n: PNode;
+                         owner: PSym = nil): PNode =
+  var typeMap = initLayeredTypeMap(pt)
+  var cl = initTypeVars(p, typeMap, n.info, owner)
+  pushInfoContext(p.config, n.info)
+  result = prepareNode(cl, n)
+  popInfoContext(p.config)
+
 when false:
   # deadcode
   proc replaceTypesForLambda*(p: PContext, pt: TIdTable, n: PNode;