fixes #7937 (#11244)

compiler/semmagic.nim

@@ -93,9 +93,10 @@ proc semInstantiationInfo(c: PContext, n: PNode): PNode =
   line.intVal = toLinenumber(info)
   var column = newNodeIT(nkIntLit, n.info, getSysType(c.graph, n.info, tyInt))
   column.intVal = toColumn(info)
-  result.add(filename)
+  # filename: string, line: int, column: int
-  result.add(line)
+  result.add(newTree(nkExprColonExpr, n.typ.n[0], filename))
-  result.add(column)
+  result.add(newTree(nkExprColonExpr, n.typ.n[1], line))
+  result.add(newTree(nkExprColonExpr, n.typ.n[2], column))
 
 proc toNode(t: PType, i: TLineInfo): PNode =
   result = newNodeIT(nkType, i, t)

tests/template/tgensym_instantiationinfo.nim

@@ -0,0 +1,24 @@
+discard """
+  action: "compile"
+"""
+
+# bug #7937
+
+template printError(error: typed) =
+  # Error: inconsistent typing for reintroduced symbol 'instInfo': previous type was: tuple[filename: string, line: int, column: int]; new type is: tuple of (string, int, int)
+  let instInfo {.gensym.} = instantiationInfo()
+  echo "Error at ", instInfo.filename, ':', instInfo.line, ": ", error
+
+# Removing this overload fixes the error
+template someTemplate(someBool: bool, body) =
+  discard
+
+template someTemplate(body) =
+  body
+
+proc main() =
+  someTemplate:
+    printError("ERROR 1")
+    printError("ERROR 2")
+
+main()