diff --git a/racket/src/expander/namespace/module.rkt b/racket/src/expander/namespace/module.rkt
index 58c0063464..466a7afb75 100644
--- a/racket/src/expander/namespace/module.rkt
+++ b/racket/src/expander/namespace/module.rkt
@@ -205,7 +205,7 @@
     ;; Register this module's exports for use in resolving bulk
     ;; bindings, so that bulk bindings can be shared among other
     ;; modules when unmarshaling; we don't do this without
-    ;; `with-submodules?` to avoid loeaking submodules being
+    ;; `with-submodules?` to avoid leaking submodules being
     ;; expanded, but see also `bind-all-provides!`
     (register-bulk-provide! (namespace-bulk-binding-registry ns)
                             mod-name
@@ -223,7 +223,9 @@
 
     (define at-phase (hash-ref (namespace-module-instances ns) phase))
     (hash-set! at-phase mod-name (make-module-instance m-ns m))
-               
+
+    (set-module-instance-shifted-requires! prior-mi #f)
+
     (when visit?
       (namespace-module-visit! ns (namespace-mpi m-ns) phase))
     (when run?
@@ -369,7 +371,8 @@
 (define (namespace-module-instantiate! ns mpi instance-phase #:run-phase [run-phase (namespace-phase ns)]
                                        #:skip-run? [skip-run? #f]
                                        #:otherwise-available? [otherwise-available? #t]
-                                       #:seen [seen #hasheq()])
+                                       #:seen [seen #hasheq()]
+                                       #:seen-list [seen-list null])
   (unless (module-path-index? mpi)
     (error "not a module path index:" mpi))
   (define name (module-path-index-resolve mpi #t))
@@ -382,7 +385,8 @@
     (run-module-instance! mi ns #:run-phase run-phase
                           #:skip-run? skip-run?
                           #:otherwise-available? otherwise-available?
-                          #:seen seen))
+                          #:seen seen
+                          #:seen-list seen-list))
   ;; If the module is cross-phase persistent, make sure it's instantiated
   ;; at phase 0 and registered in `ns` as phaseless; otherwise
   (cond
@@ -408,7 +412,8 @@
 (define (run-module-instance! mi ns #:run-phase run-phase
                               #:skip-run? skip-run? 
                               #:otherwise-available? otherwise-available?
-                              #:seen [seen #hasheq()])
+                              #:seen [seen #hasheq()]
+                              #:seen-list [seen-list null])
   (performance-region
    ['eval 'requires]
    ;; Nothing to do if we've run this phase already and made the
@@ -429,7 +434,11 @@
      (define bulk-binding-registry (namespace-bulk-binding-registry m-ns))
      
      (when (hash-ref seen mi #f)
-       (error 'require "import cycle detected during module instantiation"))
+       (error 'require
+              (apply string-append
+                     "import cycle detected during module instantiation\n"
+                     "  dependency chain:"
+                     (module-instances->indented-module-names mi seen-list))))
 
      ;; If we haven't shifted required mpis already, do that
      (unless (module-instance-shifted-requires mi)
@@ -450,7 +459,8 @@
                                         #:run-phase run-phase
                                         #:skip-run? skip-run?
                                         #:otherwise-available? otherwise-available?
-                                        #:seen (hash-set seen mi #t))))
+                                        #:seen (hash-set seen mi #t)
+                                        #:seen-list (cons mi seen-list))))
      
      ;; Run or make available phases of the module body:
      (unless (label-phase? instance-phase)
@@ -558,3 +568,19 @@
                             'provided))))))
   (set-module-access! m access)
   access)
+
+;; ----------------------------------------
+
+(define (module-instances->indented-module-names mi seen-list)
+  (let ([mi->name (lambda (mi)
+                    (format "\n   ~a" (module-path-index-resolve
+                                       (namespace-mpi (module-instance-namespace mi)))))])
+    (cons
+     (mi->name mi)
+     (let loop ([seen-list seen-list])
+       (cond
+         [(null? seen-list) '()]
+         [(eq? mi (car seen-list))
+          (list (mi->name mi))]
+         [else
+          (cons (mi->name (car seen-list)) (loop (cdr seen-list)))])))))
diff --git a/racket/src/racket/src/startup.inc b/racket/src/racket/src/startup.inc
index c1375b2239..13194bb929 100644
--- a/racket/src/racket/src/startup.inc
+++ b/racket/src/racket/src/startup.inc
@@ -14034,38 +14034,38 @@ static const char *startup_source =
 "(let-values(((name_0)(1/module-path-index-resolve name-mpi_0)))"
 "(let-values(((m-ns_0)"
 "(let-values(((the-struct_0)"
-"(let-values(((ns134_0) ns_0)"
-"((root-expand-ctx135_0) root-expand-ctx_0)"
-"((temp136_0) #f))"
-"(new-namespace.1 temp136_0 root-expand-ctx135_0 ns134_0))))"
+"(let-values(((ns138_0) ns_0)"
+"((root-expand-ctx139_0) root-expand-ctx_0)"
+"((temp140_0) #f))"
+"(new-namespace.1 temp140_0 root-expand-ctx139_0 ns138_0))))"
 "(if(1/namespace? the-struct_0)"
-"(let-values(((mpi126_0) name-mpi_0)"
-"((source-name127_0)(resolved-module-path-root-name name_0))"
-"((phase128_0) phase_0)"
-"((0-phase129_0) phase_0)"
-"((submodule-declarations130_0)"
+"(let-values(((mpi130_0) name-mpi_0)"
+"((source-name131_0)(resolved-module-path-root-name name_0))"
+"((phase132_0) phase_0)"
+"((0-phase133_0) phase_0)"
+"((submodule-declarations134_0)"
 "(if for-submodule?_0"
 "(namespace-submodule-declarations ns_0)"
 "(make-small-hasheq)))"
-"((available-module-instances131_0)(make-hasheqv))"
-"((module-instances132_0)(make-hasheqv))"
-"((declaration-inspector133_0)(current-code-inspector)))"
+"((available-module-instances135_0)(make-hasheqv))"
+"((module-instances136_0)(make-hasheqv))"
+"((declaration-inspector137_0)(current-code-inspector)))"
 "(namespace1.1"
-" mpi126_0"
-" source-name127_0"
+" mpi130_0"
+" source-name131_0"
 "(namespace-root-expand-ctx the-struct_0)"
-" phase128_0"
-" 0-phase129_0"
+" phase132_0"
+" 0-phase133_0"
 "(namespace-phase-to-namespace the-struct_0)"
 "(namespace-phase-level-to-definitions the-struct_0)"
 "(namespace-module-registry$1 the-struct_0)"
 "(namespace-bulk-binding-registry the-struct_0)"
-" submodule-declarations130_0"
+" submodule-declarations134_0"
 "(namespace-root-namespace the-struct_0)"
-" declaration-inspector133_0"
+" declaration-inspector137_0"
 "(namespace-inspector the-struct_0)"
-" available-module-instances131_0"
-" module-instances132_0))"
+" available-module-instances135_0"
+" module-instances136_0))"
 "                                      (raise-argument-error 'struct-copy \"namespace?\" the-struct_0)))))"
 "(let-values((()"
 "(begin"
@@ -14096,10 +14096,10 @@ static const char *startup_source =
 "(let-values(((prior-mi_0)"
 "(if prior-m_0"
 "(if(not(eq? m_0 prior-m_0))"
-"(let-values(((ns137_0) ns_0)"
-"((mod-name138_0) mod-name_0)"
-"((temp139_0)(namespace-phase ns_0)))"
-"(namespace->module-instance.1 #f #f void ns137_0 mod-name138_0 temp139_0))"
+"(let-values(((ns141_0) ns_0)"
+"((mod-name142_0) mod-name_0)"
+"((temp143_0)(namespace-phase ns_0)))"
+"(namespace->module-instance.1 #f #f void ns141_0 mod-name142_0 temp143_0))"
 " #f)"
 " #f)))"
 "(begin"
@@ -14129,30 +14129,32 @@ static const char *startup_source =
 "(let-values(((at-phase_0)(hash-ref(namespace-module-instances ns_0) phase_0)))"
 "(begin"
 "(hash-set! at-phase_0 mod-name_0(make-module-instance m-ns_0 m_0))"
+"(set-module-instance-shifted-requires! prior-mi_0 #f)"
 "(if visit?_0"
 "(let-values()"
-"(let-values(((ns140_0) ns_0)"
-"((temp141_0)(namespace-mpi m-ns_0))"
-"((phase142_0) phase_0))"
+"(let-values(((ns144_0) ns_0)"
+"((temp145_0)(namespace-mpi m-ns_0))"
+"((phase146_0) phase_0))"
 "(namespace-module-visit!.1"
 " unsafe-undefined"
-" ns140_0"
-" temp141_0"
-" phase142_0)))"
+" ns144_0"
+" temp145_0"
+" phase146_0)))"
 "(void))"
 "(if run?_0"
 "(let-values()"
-"(let-values(((ns143_0) ns_0)"
-"((temp144_0)(namespace-mpi m-ns_0))"
-"((phase145_0) phase_0))"
+"(let-values(((ns147_0) ns_0)"
+"((temp148_0)(namespace-mpi m-ns_0))"
+"((phase149_0) phase_0))"
 "(namespace-module-instantiate!.1"
 " #t"
 " unsafe-undefined"
 " '#hasheq()"
+" null"
 " #f"
-" ns143_0"
-" temp144_0"
-" phase145_0)))"
+" ns147_0"
+" temp148_0"
+" phase149_0)))"
 "(void))))))))))"
 "(void)))))))))))))"
 "(define-values"
@@ -14231,32 +14233,32 @@ static const char *startup_source =
 "(let-values(((m-ns_0)"
 "(let-values(((the-struct_0) ns_0))"
 "(if(1/namespace? the-struct_0)"
-"(let-values(((mpi146_0)(namespace-mpi existing-m-ns_0))"
-"((source-name147_0)(namespace-source-name existing-m-ns_0))"
-"((root-expand-ctx148_0)(box(unbox(namespace-root-expand-ctx existing-m-ns_0))))"
-"((phase149_0)(namespace-phase existing-m-ns_0))"
-"((0-phase150_0)(namespace-0-phase existing-m-ns_0))"
-"((phase-to-namespace151_0)(make-small-hasheqv))"
-"((phase-level-to-definitions152_0)"
+"(let-values(((mpi150_0)(namespace-mpi existing-m-ns_0))"
+"((source-name151_0)(namespace-source-name existing-m-ns_0))"
+"((root-expand-ctx152_0)(box(unbox(namespace-root-expand-ctx existing-m-ns_0))))"
+"((phase153_0)(namespace-phase existing-m-ns_0))"
+"((0-phase154_0)(namespace-0-phase existing-m-ns_0))"
+"((phase-to-namespace155_0)(make-small-hasheqv))"
+"((phase-level-to-definitions156_0)"
 "(if(module-cross-phase-persistent? m_0)"
 "(namespace-phase-level-to-definitions existing-m-ns_0)"
 "(make-small-hasheqv)))"
-"((declaration-inspector153_0)(module-inspector m_0))"
-"((inspector154_0)(namespace-inspector existing-m-ns_0)))"
+"((declaration-inspector157_0)(module-inspector m_0))"
+"((inspector158_0)(namespace-inspector existing-m-ns_0)))"
 "(namespace1.1"
-" mpi146_0"
-" source-name147_0"
-" root-expand-ctx148_0"
-" phase149_0"
-" 0-phase150_0"
-" phase-to-namespace151_0"
-" phase-level-to-definitions152_0"
+" mpi150_0"
+" source-name151_0"
+" root-expand-ctx152_0"
+" phase153_0"
+" 0-phase154_0"
+" phase-to-namespace155_0"
+" phase-level-to-definitions156_0"
 "(namespace-module-registry$1 the-struct_0)"
 "(namespace-bulk-binding-registry the-struct_0)"
 "(namespace-submodule-declarations the-struct_0)"
 "(namespace-root-namespace the-struct_0)"
-" declaration-inspector153_0"
-" inspector154_0"
+" declaration-inspector157_0"
+" inspector158_0"
 "(namespace-available-module-instances the-struct_0)"
 "(namespace-module-instances the-struct_0)))"
 "                        (raise-argument-error 'struct-copy \"namespace?\" the-struct_0)))))"
@@ -14310,33 +14312,33 @@ static const char *startup_source =
 "(let-values(((m-ns_0)"
 "(let-values(((the-struct_0) ns_0))"
 "(if(1/namespace? the-struct_0)"
-"(let-values(((mpi155_0) mpi_0)"
-"((source-name156_0)"
+"(let-values(((mpi159_0) mpi_0)"
+"((source-name160_0)"
 "(let-values(((or-part_0)(module-source-name m_0)))"
 "(if or-part_0"
 " or-part_0"
 "(resolved-module-path-root-name(1/module-path-index-resolve mpi_0)))))"
-"((root-expand-ctx157_0)(box #f))"
-"((phase158_0) 0-phase_0)"
-"((0-phase159_0) 0-phase_0)"
-"((phase-to-namespace160_0)(make-small-hasheqv))"
-"((phase-level-to-definitions161_0)(make-small-hasheqv))"
-"((declaration-inspector162_0)(module-inspector m_0))"
-"((inspector163_0)(make-inspector(module-inspector m_0))))"
+"((root-expand-ctx161_0)(box #f))"
+"((phase162_0) 0-phase_0)"
+"((0-phase163_0) 0-phase_0)"
+"((phase-to-namespace164_0)(make-small-hasheqv))"
+"((phase-level-to-definitions165_0)(make-small-hasheqv))"
+"((declaration-inspector166_0)(module-inspector m_0))"
+"((inspector167_0)(make-inspector(module-inspector m_0))))"
 "(namespace1.1"
-" mpi155_0"
-" source-name156_0"
-" root-expand-ctx157_0"
-" phase158_0"
-" 0-phase159_0"
-" phase-to-namespace160_0"
-" phase-level-to-definitions161_0"
+" mpi159_0"
+" source-name160_0"
+" root-expand-ctx161_0"
+" phase162_0"
+" 0-phase163_0"
+" phase-to-namespace164_0"
+" phase-level-to-definitions165_0"
 "(namespace-module-registry$1 the-struct_0)"
 "(namespace-bulk-binding-registry the-struct_0)"
 "(namespace-submodule-declarations the-struct_0)"
 "(namespace-root-namespace the-struct_0)"
-" declaration-inspector162_0"
-" inspector163_0"
+" declaration-inspector166_0"
+" inspector167_0"
 "(namespace-available-module-instances the-struct_0)"
 "(namespace-module-instances the-struct_0)))"
 "                        (raise-argument-error 'struct-copy \"namespace?\" the-struct_0)))))"
@@ -14389,49 +14391,57 @@ static const char *startup_source =
 "(let-values(((unavailable-callback_0) unavailable-callback67_0))"
 "(let-values()"
 "(let-values(((mi_0)"
-"(let-values(((ns164_0) ns_0)"
-"((name165_0) name_0)"
-"((0-phase166_0) 0-phase_0)"
-"((complain-on-failure?167_0) complain-on-failure?_0)"
-"((check-available-at-phase-level168_0) check-available-at-phase-level_0)"
-"((unavailable-callback169_0) unavailable-callback_0))"
+"(let-values(((ns168_0) ns_0)"
+"((name169_0) name_0)"
+"((0-phase170_0) 0-phase_0)"
+"((complain-on-failure?171_0) complain-on-failure?_0)"
+"((check-available-at-phase-level172_0) check-available-at-phase-level_0)"
+"((unavailable-callback173_0) unavailable-callback_0))"
 "(namespace->module-instance.1"
-" check-available-at-phase-level168_0"
-" complain-on-failure?167_0"
-" unavailable-callback169_0"
-" ns164_0"
-" name165_0"
-" 0-phase166_0))))"
+" check-available-at-phase-level172_0"
+" complain-on-failure?171_0"
+" unavailable-callback173_0"
+" ns168_0"
+" name169_0"
+" 0-phase170_0))))"
 "(if mi_0(module-instance-namespace mi_0) #f))))))))))))"
 "(define-values"
 "(namespace-record-module-instance-attached!)"
 "(lambda(ns_0 mod-name_0 phase_0)"
 "(begin"
 "(let-values(((mi_0)"
-"(let-values(((ns170_0) ns_0)((mod-name171_0) mod-name_0)((phase172_0) phase_0))"
-"(namespace->module-instance.1 #f #f void ns170_0 mod-name171_0 phase172_0))))"
+"(let-values(((ns174_0) ns_0)((mod-name175_0) mod-name_0)((phase176_0) phase_0))"
+"(namespace->module-instance.1 #f #f void ns174_0 mod-name175_0 phase176_0))))"
 "(set-module-instance-attached?! mi_0 #t)))))"
 "(define-values"
 "(module-force-bulk-binding!)"
 "(lambda(m_0 ns_0)(begin((module-force-bulk-binding m_0)(namespace-bulk-binding-registry ns_0)))))"
 "(define-values"
 "(namespace-module-instantiate!.1)"
-"(lambda(otherwise-available?77_0 run-phase75_0 seen78_0 skip-run?76_0 ns83_0 mpi84_0 instance-phase85_0)"
+"(lambda(otherwise-available?77_0"
+" run-phase75_0"
+" seen78_0"
+" seen-list79_0"
+" skip-run?76_0"
+" ns85_0"
+" mpi86_0"
+" instance-phase87_0)"
 "(begin"
 " 'namespace-module-instantiate!"
-"(let-values(((ns_0) ns83_0))"
-"(let-values(((mpi_0) mpi84_0))"
-"(let-values(((instance-phase_0) instance-phase85_0))"
+"(let-values(((ns_0) ns85_0))"
+"(let-values(((mpi_0) mpi86_0))"
+"(let-values(((instance-phase_0) instance-phase87_0))"
 "(let-values(((run-phase_0)(if(eq? run-phase75_0 unsafe-undefined)(namespace-phase ns_0) run-phase75_0)))"
 "(let-values(((skip-run?_0) skip-run?76_0))"
 "(let-values(((otherwise-available?_0) otherwise-available?77_0))"
 "(let-values(((seen_0) seen78_0))"
+"(let-values(((seen-list_0) seen-list79_0))"
 "(let-values()"
 "(let-values((()"
 "(begin"
 "(if(1/module-path-index? mpi_0)"
 "(void)"
-"                                        (let-values () (error \"not a module path index:\" mpi_0)))"
+"                                          (let-values () (error \"not a module path index:\" mpi_0)))"
 "(values))))"
 "(let-values(((name_0)(1/module-path-index-resolve mpi_0 #t)))"
 "(let-values(((m_0)(namespace->module ns_0 name_0)))"
@@ -14447,17 +14457,17 @@ static const char *startup_source =
 " 'instantiate!"
 "(let-values(((mi_0)"
 "(let-values(((or-part_0)"
-"(let-values(((ns179_0) ns_1)"
-"((name180_0) name_0)"
-"((instance-phase181_0)"
+"(let-values(((ns184_0) ns_1)"
+"((name185_0) name_0)"
+"((instance-phase186_0)"
 " instance-phase_1))"
 "(namespace->module-instance.1"
 " #f"
 " #f"
 " void"
-" ns179_0"
-" name180_0"
-" instance-phase181_0))))"
+" ns184_0"
+" name185_0"
+" instance-phase186_0))))"
 "(if or-part_0"
 " or-part_0"
 "(namespace-create-module-instance!"
@@ -14466,19 +14476,21 @@ static const char *startup_source =
 " instance-phase_1"
 " m_0"
 " mpi_0)))))"
-"(let-values(((mi173_0) mi_0)"
-"((ns174_0) ns_1)"
-"((run-phase175_0) run-phase_1)"
-"((skip-run?176_0) skip-run?_0)"
-"((otherwise-available?177_0) otherwise-available?_0)"
-"((seen178_0) seen_0))"
+"(let-values(((mi177_0) mi_0)"
+"((ns178_0) ns_1)"
+"((run-phase179_0) run-phase_1)"
+"((skip-run?180_0) skip-run?_0)"
+"((otherwise-available?181_0) otherwise-available?_0)"
+"((seen182_0) seen_0)"
+"((seen-list183_0) seen-list_0))"
 "(run-module-instance!.1"
-" otherwise-available?177_0"
-" run-phase175_0"
-" seen178_0"
-" skip-run?176_0"
-" mi173_0"
-" ns174_0)))))))"
+" otherwise-available?181_0"
+" run-phase179_0"
+" seen182_0"
+" seen-list183_0"
+" skip-run?180_0"
+" mi177_0"
+" ns178_0)))))))"
 "(if(module-cross-phase-persistent? m_0)"
 "(let-values()"
 "(instantiate!_0"
@@ -14486,65 +14498,68 @@ static const char *startup_source =
 " 0"
 "(let-values(((or-part_0)(namespace-root-namespace ns_0)))"
 "(if or-part_0 or-part_0 ns_0))))"
-"(let-values()(instantiate!_0 instance-phase_0 run-phase_0 ns_0)))))))))))))))))))"
+"(let-values()(instantiate!_0 instance-phase_0 run-phase_0 ns_0))))))))))))))))))))"
 "(define-values"
 "(namespace-module-visit!.1)"
-"(lambda(visit-phase87_0 ns89_0 mpi90_0 instance-phase91_0)"
+"(lambda(visit-phase89_0 ns91_0 mpi92_0 instance-phase93_0)"
 "(begin"
 " 'namespace-module-visit!"
-"(let-values(((ns_0) ns89_0))"
-"(let-values(((mpi_0) mpi90_0))"
-"(let-values(((instance-phase_0) instance-phase91_0))"
+"(let-values(((ns_0) ns91_0))"
+"(let-values(((mpi_0) mpi92_0))"
+"(let-values(((instance-phase_0) instance-phase93_0))"
 "(let-values(((visit-phase_0)"
-"(if(eq? visit-phase87_0 unsafe-undefined)(namespace-phase ns_0) visit-phase87_0)))"
+"(if(eq? visit-phase89_0 unsafe-undefined)(namespace-phase ns_0) visit-phase89_0)))"
 "(let-values()"
-"(let-values(((ns182_0) ns_0)"
-"((mpi183_0) mpi_0)"
-"((instance-phase184_0) instance-phase_0)"
-"((temp185_0)(add1 visit-phase_0)))"
+"(let-values(((ns187_0) ns_0)"
+"((mpi188_0) mpi_0)"
+"((instance-phase189_0) instance-phase_0)"
+"((temp190_0)(add1 visit-phase_0)))"
 "(namespace-module-instantiate!.1"
 " #t"
-" temp185_0"
+" temp190_0"
 " '#hasheq()"
+" null"
 " #f"
-" ns182_0"
-" mpi183_0"
-" instance-phase184_0))))))))))"
+" ns187_0"
+" mpi188_0"
+" instance-phase189_0))))))))))"
 "(define-values"
 "(namespace-module-make-available!.1)"
-"(lambda(visit-phase93_0 ns95_0 mpi96_0 instance-phase97_0)"
+"(lambda(visit-phase95_0 ns97_0 mpi98_0 instance-phase99_0)"
 "(begin"
 " 'namespace-module-make-available!"
-"(let-values(((ns_0) ns95_0))"
-"(let-values(((mpi_0) mpi96_0))"
-"(let-values(((instance-phase_0) instance-phase97_0))"
+"(let-values(((ns_0) ns97_0))"
+"(let-values(((mpi_0) mpi98_0))"
+"(let-values(((instance-phase_0) instance-phase99_0))"
 "(let-values(((visit-phase_0)"
-"(if(eq? visit-phase93_0 unsafe-undefined)(namespace-phase ns_0) visit-phase93_0)))"
+"(if(eq? visit-phase95_0 unsafe-undefined)(namespace-phase ns_0) visit-phase95_0)))"
 "(let-values()"
-"(let-values(((ns186_0) ns_0)"
-"((mpi187_0) mpi_0)"
-"((instance-phase188_0) instance-phase_0)"
-"((temp189_0)(add1 visit-phase_0))"
-"((temp190_0) #t))"
+"(let-values(((ns191_0) ns_0)"
+"((mpi192_0) mpi_0)"
+"((instance-phase193_0) instance-phase_0)"
+"((temp194_0)(add1 visit-phase_0))"
+"((temp195_0) #t))"
 "(namespace-module-instantiate!.1"
 " #t"
-" temp189_0"
+" temp194_0"
 " '#hasheq()"
-" temp190_0"
-" ns186_0"
-" mpi187_0"
-" instance-phase188_0))))))))))"
+" null"
+" temp195_0"
+" ns191_0"
+" mpi192_0"
+" instance-phase193_0))))))))))"
 "(define-values"
 "(run-module-instance!.1)"
-"(lambda(otherwise-available?101_0 run-phase99_0 seen102_0 skip-run?100_0 mi107_0 ns108_0)"
+"(lambda(otherwise-available?103_0 run-phase101_0 seen104_0 seen-list105_0 skip-run?102_0 mi111_0 ns112_0)"
 "(begin"
 " 'run-module-instance!"
-"(let-values(((mi_0) mi107_0))"
-"(let-values(((ns_0) ns108_0))"
-"(let-values(((run-phase_0) run-phase99_0))"
-"(let-values(((skip-run?_0) skip-run?100_0))"
-"(let-values(((otherwise-available?_0) otherwise-available?101_0))"
-"(let-values(((seen_0) seen102_0))"
+"(let-values(((mi_0) mi111_0))"
+"(let-values(((ns_0) ns112_0))"
+"(let-values(((run-phase_0) run-phase101_0))"
+"(let-values(((skip-run?_0) skip-run?102_0))"
+"(let-values(((otherwise-available?_0) otherwise-available?103_0))"
+"(let-values(((seen_0) seen104_0))"
+"(let-values(((seen-list_0) seen-list105_0))"
 "(let-values()"
 "(begin"
 "(if log-performance?(let-values()(start-performance-region 'eval 'requires))(void))"
@@ -14575,7 +14590,7 @@ static const char *startup_source =
 "(let-values()"
 "(error"
 " 'require"
-"                                                           \"import cycle detected; trying to run module being expanded\")))"
+"                                                             \"import cycle detected; trying to run module being expanded\")))"
 "(values))))"
 "(let-values(((mpi_0)(namespace-mpi m-ns_0)))"
 "(let-values(((phase-shift_0) instance-phase_0))"
@@ -14586,7 +14601,11 @@ static const char *startup_source =
 "(let-values()"
 "(error"
 " 'require"
-"                                                     \"import cycle detected during module instantiation\"))"
+"(apply"
+" string-append"
+"                                                        \"import cycle detected during module instantiation\\n\""
+"                                                        \"  dependency chain:\""
+"(module-instances->indented-module-names mi_0 seen-list_0))))"
 "(void))"
 "(if(module-instance-shifted-requires mi_0)"
 "(void)"
@@ -14689,7 +14708,8 @@ static const char *startup_source =
 "(if(pair? lst_1)"
 "(let-values(((phase+mpis_0)"
 "(unsafe-car lst_1))"
-"((rest_0)(unsafe-cdr lst_1)))"
+"((rest_0)"
+"(unsafe-cdr lst_1)))"
 "(let-values((()"
 "(let-values()"
 "(let-values((()"
@@ -14728,33 +14748,38 @@ static const char *startup_source =
 "(let-values()"
 "(begin"
 "(let-values()"
-"(let-values(((ns191_0)"
+"(let-values(((ns196_0)"
 " ns_0)"
-"((req-mpi192_0)"
+"((req-mpi197_0)"
 " req-mpi_0)"
-"((temp193_0)"
+"((temp198_0)"
 "(phase+"
 " instance-phase_0"
 " req-phase_0))"
-"((run-phase194_0)"
+"((run-phase199_0)"
 " run-phase_0)"
-"((skip-run?195_0)"
+"((skip-run?200_0)"
 " skip-run?_0)"
-"((otherwise-available?196_0)"
+"((otherwise-available?201_0)"
 " otherwise-available?_0)"
-"((temp197_0)"
+"((temp202_0)"
 "(hash-set"
 " seen_0"
 " mi_0"
-" #t)))"
+" #t))"
+"((temp203_0)"
+"(cons"
+" mi_0"
+" seen-list_0)))"
 "(namespace-module-instantiate!.1"
-" otherwise-available?196_0"
-" run-phase194_0"
-" temp197_0"
-" skip-run?195_0"
-" ns191_0"
-" req-mpi192_0"
-" temp193_0)))"
+" otherwise-available?201_0"
+" run-phase199_0"
+" temp202_0"
+" temp203_0"
+" skip-run?200_0"
+" ns196_0"
+" req-mpi197_0"
+" temp198_0)))"
 "(values)))))"
 "(values)))))"
 "(if(not"
@@ -14791,7 +14816,8 @@ static const char *startup_source =
 "(begin"
 " 'for-loop"
 "(if(> pos_0 end_0)"
-"(let-values(((phase-level_0) pos_0))"
+"(let-values(((phase-level_0)"
+" pos_0))"
 "(let-values((()"
 "(let-values()"
 "(let-values((()"
@@ -14913,29 +14939,29 @@ static const char *startup_source =
 "(module-instance-phase-level-to-state mi_0)"
 " run-phase-level_0"
 " 'started)))))))))))))))"
-"(if log-performance?(let-values()(end-performance-region))(void))))))))))))))"
+"(if log-performance?(let-values()(end-performance-region))(void)))))))))))))))"
 "(define-values"
 "(namespace-visit-available-modules!)"
 "(let-values(((namespace-visit-available-modules!_0)"
-"(lambda(ns111_0 run-phase110_0)"
+"(lambda(ns115_0 run-phase114_0)"
 "(begin"
 " 'namespace-visit-available-modules!"
-"(let-values(((ns_0) ns111_0))"
+"(let-values(((ns_0) ns115_0))"
 "(let-values(((run-phase_0)"
-"(if(eq? run-phase110_0 unsafe-undefined)(namespace-phase ns_0) run-phase110_0)))"
+"(if(eq? run-phase114_0 unsafe-undefined)(namespace-phase ns_0) run-phase114_0)))"
 "(let-values()(namespace-run-available-modules! ns_0(add1 run-phase_0)))))))))"
 "(case-lambda"
 "((ns_0)(begin(namespace-visit-available-modules!_0 ns_0 unsafe-undefined)))"
-"((ns_0 run-phase110_0)(namespace-visit-available-modules!_0 ns_0 run-phase110_0)))))"
+"((ns_0 run-phase114_0)(namespace-visit-available-modules!_0 ns_0 run-phase114_0)))))"
 "(define-values"
 "(namespace-run-available-modules!)"
 "(let-values(((namespace-run-available-modules!_0)"
-"(lambda(ns113_0 run-phase112_0)"
+"(lambda(ns117_0 run-phase116_0)"
 "(begin"
 " 'namespace-run-available-modules!"
-"(let-values(((ns_0) ns113_0))"
+"(let-values(((ns_0) ns117_0))"
 "(let-values(((run-phase_0)"
-"(if(eq? run-phase112_0 unsafe-undefined)(namespace-phase ns_0) run-phase112_0)))"
+"(if(eq? run-phase116_0 unsafe-undefined)(namespace-phase ns_0) run-phase116_0)))"
 "(let-values()"
 "(registry-call-with-lock"
 "(namespace-module-registry$1 ns_0)"
@@ -14979,23 +15005,24 @@ static const char *startup_source =
 "(let-values()"
 "(begin"
 "(let-values()"
-"(let-values(((mi198_0)"
+"(let-values(((mi204_0)"
 " mi_0)"
-"((ns199_0)"
+"((ns205_0)"
 " ns_0)"
-"((run-phase200_0)"
+"((run-phase206_0)"
 " run-phase_0)"
-"((temp201_0)"
+"((temp207_0)"
 " #f)"
-"((temp202_0)"
+"((temp208_0)"
 " #f))"
 "(run-module-instance!.1"
-" temp202_0"
-" run-phase200_0"
+" temp208_0"
+" run-phase206_0"
 " '#hasheq()"
-" temp201_0"
-" mi198_0"
-" ns199_0)))"
+" null"
+" temp207_0"
+" mi204_0"
+" ns205_0)))"
 "(values)))))"
 "(values)))))"
 "(if(not #f)"
@@ -15009,42 +15036,42 @@ static const char *startup_source =
 " loop_0)))))))))))"
 "(case-lambda"
 "((ns_0)(begin(namespace-run-available-modules!_0 ns_0 unsafe-undefined)))"
-"((ns_0 run-phase112_0)(namespace-run-available-modules!_0 ns_0 run-phase112_0)))))"
+"((ns_0 run-phase116_0)(namespace-run-available-modules!_0 ns_0 run-phase116_0)))))"
 "(define-values"
 "(namespace-primitive-module-visit!)"
 "(lambda(ns_0 name_0)"
 "(begin"
 "(let-values(((mi_0)(hash-ref(namespace-module-instances ns_0)(1/make-resolved-module-path name_0))))"
-"(let-values(((mi203_0) mi_0)((ns204_0) ns_0)((temp205_0) 1)((temp206_0) #f)((temp207_0) #t))"
-"(run-module-instance!.1 temp207_0 temp205_0 '#hasheq() temp206_0 mi203_0 ns204_0))))))"
+"(let-values(((mi209_0) mi_0)((ns210_0) ns_0)((temp211_0) 1)((temp212_0) #f)((temp213_0) #t))"
+"(run-module-instance!.1 temp213_0 temp211_0 '#hasheq() null temp212_0 mi209_0 ns210_0))))))"
 "(define-values"
 "(namespace-module-use->module+linklet-instances.1)"
-"(lambda(phase-shift116_0 shift-from114_0 shift-to115_0 ns120_0 mu121_0)"
+"(lambda(phase-shift120_0 shift-from118_0 shift-to119_0 ns124_0 mu125_0)"
 "(begin"
 " 'namespace-module-use->module+linklet-instances"
-"(let-values(((ns_0) ns120_0))"
-"(let-values(((mu_0) mu121_0))"
-"(let-values(((shift-from_0) shift-from114_0))"
-"(let-values(((shift-to_0) shift-to115_0))"
-"(let-values(((phase-shift_0) phase-shift116_0))"
+"(let-values(((ns_0) ns124_0))"
+"(let-values(((mu_0) mu125_0))"
+"(let-values(((shift-from_0) shift-from118_0))"
+"(let-values(((shift-to_0) shift-to119_0))"
+"(let-values(((phase-shift_0) phase-shift120_0))"
 "(let-values()"
 "(let-values(((mod_0)(module-use-module mu_0)))"
 "(let-values(((mi_0)"
-"(let-values(((ns208_0) ns_0)"
-"((temp209_0)"
+"(let-values(((ns214_0) ns_0)"
+"((temp215_0)"
 "(1/module-path-index-resolve"
 "(if shift-from_0"
 "(module-path-index-shift mod_0 shift-from_0 shift-to_0)"
 " mod_0)))"
-"((phase-shift210_0) phase-shift_0)"
-"((temp211_0) #t))"
+"((phase-shift216_0) phase-shift_0)"
+"((temp217_0) #t))"
 "(namespace->module-instance.1"
 " #f"
-" temp211_0"
+" temp217_0"
 " void"
-" ns208_0"
-" temp209_0"
-" phase-shift210_0))))"
+" ns214_0"
+" temp215_0"
+" phase-shift216_0))))"
 "(let-values(((m-ns_0)(module-instance-namespace mi_0)))"
 "(let-values(((d_0)"
 "(small-hash-ref"
@@ -15222,6 +15249,31 @@ static const char *startup_source =
 "(hash-iterate-first ht_0))))))"
 "(begin(set-module-access! m_0 access_0) access_0)))))"
 "(define-values"
+"(module-instances->indented-module-names)"
+"(lambda(mi_0 seen-list_0)"
+"(begin"
+"(let-values(((mi->name_0)"
+"(lambda(mi_1)"
+"(begin"
+" 'mi->name"
+"(format"
+"                         \"\\n   ~a\""
+"(1/module-path-index-resolve(namespace-mpi(module-instance-namespace mi_1))))))))"
+"(cons"
+"(mi->name_0 mi_0)"
+"((letrec-values(((loop_0)"
+"(lambda(seen-list_1)"
+"(begin"
+" 'loop"
+"(if(null? seen-list_1)"
+"(let-values() '())"
+"(if(eq? mi_0(car seen-list_1))"
+"(let-values()(list(mi->name_0 mi_0)))"
+"(let-values()"
+"(cons(mi->name_0(car seen-list_1))(loop_0(cdr seen-list_1))))))))))"
+" loop_0)"
+" seen-list_0))))))"
+"(define-values"
 "(binding->module-instance)"
 "(lambda(b_0 ns_0 phase_0 id_0)"
 "(begin"
@@ -28232,6 +28284,7 @@ static const char *startup_source =
 " #t"
 " run-phase248_0"
 " '#hasheq()"
+" null"
 " #f"
 " m-ns245_0"
 " interned-mpi246_0"
@@ -49034,6 +49087,7 @@ static const char *startup_source =
 " #t"
 " unsafe-undefined"
 " '#hasheq()"
+" null"
 " #f"
 " src-namespace35_0"
 " mpi36_0"
@@ -51891,6 +51945,7 @@ static const char *startup_source =
 " temp15_0"
 " phase14_0"
 " '#hasheq()"
+" null"
 " #f"
 " ns11_0"
 " mpi12_0"
@@ -51905,6 +51960,7 @@ static const char *startup_source =
 " #t"
 " phase19_0"
 " '#hasheq()"
+" null"
 " #f"
 " ns16_0"
 " mpi17_0"
@@ -51967,6 +52023,7 @@ static const char *startup_source =
 " temp28_0"
 " phase27_0"
 " '#hasheq()"
+" null"
 " #f"
 " ns24_0"
 " mpi25_0"