fixes #26158; incRef: interiorPtrTraceback/SIGSEGV with closure itera… (#26162)

…tor iterating over tuples in refc

fixes #26158

compiler/ccgexprs.nim

@@ -424,7 +424,15 @@ proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
       simpleAsgn(p.s(cpsStmts), dest, src)
   of tyArray:
     if containsGarbageCollectedRef(dest.t) and p.config.selectedGC notin {gcArc, gcAtomicArc, gcOrc, gcYrc, gcHooks}:
-      genGenericAsgn(p, dest, src, flags)
+      # Static array literals may contain GC-managed values (for example,
+      # strings). They must be copied deeply so that the destination does not
+      # attempt to adjust the reference count of the static literal's
+      # interior pointers. This mirrors the handling for tuples and objects
+      # above, where static sources force a real copy.
+      let newflags =
+        if src.storage == OnStatic: flags + {needToCopy}
+        else: flags
+      genGenericAsgn(p, dest, src, newflags)
     else:
       let rd = rdLoc(dest)
       let rs = rdLoc(src)

tests/iter/tclosureiters.nim

@@ -174,3 +174,19 @@ iterator pairs(): (int, int) {.closure.} =
 
 for pair in pairs():
   echo pair
+
+# issue #26158: static array literals containing strings must be copied safely
+# when a closure iterator stores them in its environment.
+iterator fromStatic(): int {.closure.} =
+  for _ in static([(" ",)]):
+    break
+
+for _ in fromStatic():
+  break
+
+iterator fromLiteral(): int {.closure.} =
+  for _ in [(" ",)]:
+    break
+
+for _ in fromLiteral():
+  break