diff --git a/compiler/semcall.nim b/compiler/semcall.nim
index fb2f9e97a78e..d0ccb17b1fa1 100644
--- a/compiler/semcall.nim
+++ b/compiler/semcall.nim
@@ -973,8 +973,14 @@ proc explicitGenericInstantiation(c: PContext, n: PNode, s: PSym, doError: bool)
     # common case; check the only candidate has the right
     # number of generic type parameters:
     result = explicitGenericSym(c, n, s, errors, doError)
-    if doError and result == nil:
-      notFoundError(c, n, errors)
+    if result == nil:
+      if c.inGenericContext > 0:
+        # same as in semOverloadedCall, make expression untyped,
+        # may have failed match due to unresolved types
+        result = semGenericStmt(c, n)
+        result.typ() = makeTypeFromExpr(c, result.copyTree)
+      elif doError:
+        notFoundError(c, n, errors)
   elif a.kind in {nkClosedSymChoice, nkOpenSymChoice}:
     # choose the generic proc with the proper number of type parameters.
     result = newNodeI(a.kind, getCallLineInfo(n))
@@ -984,6 +990,14 @@ proc explicitGenericInstantiation(c: PContext, n: PNode, s: PSym, doError: bool)
                             skFunc, skIterator}:
         let x = explicitGenericSym(c, n, candidate, errors, doError)
         if x != nil: result.add(x)
+        elif c.inGenericContext > 0:
+          # same as in semOverloadedCall, make expression untyped,
+          # may have failed match due to unresolved types
+          # any failing match stops building the symchoice for correctness,
+          # can also make it untyped from the start
+          result = semGenericStmt(c, n)
+          result.typ() = makeTypeFromExpr(c, result.copyTree)
+          return
     # get rid of nkClosedSymChoice if not ambiguous:
     if result.len == 0:
       result = nil
diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 6cc4afd6e008..e4c585e0130d 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -1816,7 +1816,9 @@ proc semSubscript(c: PContext, n: PNode, flags: TExprFlags, afterOverloading = f
         # type parameters: partial generic specialization
         n[0] = semSymGenericInstantiation(c, n[0], s)
         result = maybeInstantiateGeneric(c, n, s, doError = afterOverloading)
-        if result != nil:
+        if result != nil and
+            # leave untyped generic expression alone:
+            (result.typ == nil or result.typ.kind != tyFromExpr):
           # check newly created sym/symchoice
           result = semExpr(c, result, flags)
       of skMacro, skTemplate:
diff --git a/tests/proc/texplicitgenerics.nim b/tests/proc/texplicitgenerics.nim
index 833d77b3b790..131a31458d5c 100644
--- a/tests/proc/texplicitgenerics.nim
+++ b/tests/proc/texplicitgenerics.nim
@@ -53,3 +53,11 @@ block: # issue #21346
   b1(false)     # Error: cannot instantiate K; got: <T> but expected: <T>
   b2(false)     # Builds, on its own
   b3(false)
+
+block: # explicit generic with unresolved generic param, https://forum.nim-lang.org/t/12579
+  var s: seq[string] = @[]
+  proc MyMedian[T](A: var openArray[T],myCmp : proc(x,y:T):int {.nimcall.} = cmp[T]) : T =
+    if myCmp(A[0], A[1]) == 0: s.add("1")
+  var x = [1, 1]
+  discard MyMedian(x) # emits "1\n"
+  doAssert s == @["1"]