diff --git a/cabal-install/src/Distribution/Client/ProjectPlanning.hs b/cabal-install/src/Distribution/Client/ProjectPlanning.hs
index c04bca730d7..3e567892d58 100644
--- a/cabal-install/src/Distribution/Client/ProjectPlanning.hs
+++ b/cabal-install/src/Distribution/Client/ProjectPlanning.hs
@@ -2319,13 +2319,13 @@ elaborateInstallPlan
                 ]
                 <> perPkgOptionMapLast pkgid packageConfigProgramPaths
             elabProgramArgs =
-              Map.fromList
+              Map.unionWith (++) (Map.fromList
                 [ (programId prog, args)
                 | prog <- configuredPrograms compilerprogdb
                 , let args = programOverrideArgs $ addHaddockIfDocumentationEnabled prog
                 , not (null args)
-                ]
-                <> perPkgOptionMapMappend pkgid packageConfigProgramArgs
+                ])
+                (perPkgOptionMapMappend pkgid packageConfigProgramArgs)
             elabProgramPathExtra = perPkgOptionNubList pkgid packageConfigProgramPathExtra
             elabConfigureScriptArgs = perPkgOptionList pkgid packageConfigConfigureArgs
             elabExtraLibDirs = perPkgOptionList pkgid packageConfigExtraLibDirs