Check expressions: safer init properties check (dotnet#13892)

auduchinok · web-flow · commit cdc596316c61 · 2022-09-13T18:09:06.000+02:00
diff --git a/src/Compiler/Checking/CheckExpressions.fs b/src/Compiler/Checking/CheckExpressions.fs
@@ -8921,8 +8921,11 @@ and TcLookupItemThen cenv overallTy env tpenv mObjExpr objExpr objExprTy delayed
         // To get better warnings we special case some of the few known mutate-a-struct method names
         let mutates = (if methodName = "MoveNext" || methodName = "GetNextArg" then DefinitelyMutates else PossiblyMutates)
 
-        // Check if we have properties with "init-only" setters, which we try to call after init is done.
-        CheckInitProperties g (List.head minfos) methodName mItem
+        match minfos with
+        | minfo :: _ ->
+            // Check if we have properties with "init-only" setters, which we try to call after init is done.
+            CheckInitProperties g minfo methodName mItem
+        | _ -> ()
 
 #if !NO_TYPEPROVIDERS
         match TryTcMethodAppToStaticConstantArgs cenv env tpenv (minfos, tyArgsOpt, mExprAndItem, mItem) with
