diff --git a/mps/code/apss.c b/mps/code/apss.c
index 04818600510..6e4c7f3a71b 100644
--- a/mps/code/apss.c
+++ b/mps/code/apss.c
@@ -122,16 +122,9 @@ static size_t randomSizeAligned(size_t i)
 }
 
 
-static mps_pool_debug_option_s bothOptions8 = {
-  /* .fence_template = */   (const void *)"postpost",
-  /* .fence_size = */       8,
-  /* .free_template = */    (const void *)"DEAD",
-  /* .free_size = */        4
-};
-
-static mps_pool_debug_option_s bothOptions16 = {
+static mps_pool_debug_option_s bothOptions = {
   /* .fence_template = */   (const void *)"postpostpostpost",
-  /* .fence_size = */       16,
+  /* .fence_size = */       MPS_PF_ALIGN,
   /* .free_template = */    (const void *)"DEAD",
   /* .free_size = */        4
 };
@@ -181,9 +174,6 @@ static void testInArena(mps_arena_t arena, mps_pool_debug_option_s *options)
 int main(int argc, char *argv[])
 {
   mps_arena_t arena;
-  mps_pool_debug_option_s *bothOptions;
-  
-  bothOptions = MPS_PF_ALIGN == 8 ? &bothOptions8 : &bothOptions16;
 
   testlib_init(argc, argv);
 
@@ -200,7 +190,7 @@ int main(int argc, char *argv[])
     die(mps_arena_create_k(&arena, mps_arena_class_vm(), args),
         "mps_arena_create");
   } MPS_ARGS_END(args);
-  testInArena(arena, bothOptions);
+  testInArena(arena, &bothOptions);
   mps_arena_destroy(arena);
 
   MPS_ARGS_BEGIN(args) {
@@ -210,7 +200,7 @@ int main(int argc, char *argv[])
     die(mps_arena_create_k(&arena, mps_arena_class_cl(), args),
         "mps_arena_create");
   } MPS_ARGS_END(args);
-  testInArena(arena, bothOptions);
+  testInArena(arena, &bothOptions);
   mps_arena_destroy(arena);
 
   printf("%s: Conclusion: Failed to find any defects.\n", argv[0]);
diff --git a/mps/code/gc.gmk b/mps/code/gc.gmk
index 8ff258c9cf3..e6bd343f11b 100644
--- a/mps/code/gc.gmk
+++ b/mps/code/gc.gmk
@@ -3,7 +3,7 @@
 # gc.gmk: GNUMAKEFILE FRAGMENT FOR GNU CC
 #
 # $Id$
-# Copyright (c) 2001-2013 Ravenbrook Limited.  See end of file for license.
+# Copyright (c) 2001-2014 Ravenbrook Limited.  See end of file for license.
 #
 # This file is included by platform makefiles that use the GNU CC
 # compiler.  It defines the compiler-specific variables that the
@@ -12,11 +12,23 @@
 CC = gcc
 CFLAGSDEBUG = -O -g3
 CFLAGSOPT = -O2 -g3
-CFLAGSCOMPILER :=  -Wall -Wextra -Werror -Wpointer-arith \
-	-Wstrict-prototypes -Wmissing-prototypes \
-	-Winline -Waggregate-return -Wnested-externs \
-	-Wcast-qual -Wshadow -Wwrite-strings # -Wstrict-aliasing=2
-CFLAGSCOMPILERSTRICT := -ansi -pedantic -Wshadow
+CFLAGSCOMPILER := \
+	-pedantic \
+	-Waggregate-return \
+	-Wall \
+	-Wcast-qual \
+	-Werror \
+	-Wextra \
+	-Winline \
+	-Wmissing-prototypes \
+	-Wnested-externs \
+	-Wpointer-arith \
+	-Wshadow \
+	-Wstrict-aliasing=2 \
+	-Wstrict-prototypes \
+	-Wunreachable-code \
+	-Wwrite-strings
+CFLAGSCOMPILERSTRICT := -ansi
 
 # A different set of compiler flags for less strict compilation, for
 # instance when we need to #include a third-party header file that
@@ -38,7 +50,7 @@ endef
 
 # C. COPYRIGHT AND LICENSE
 #
-# Copyright (C) 2001-2013 Ravenbrook Limited <http://www.ravenbrook.com/>.
+# Copyright (C) 2001-2014 Ravenbrook Limited <http://www.ravenbrook.com/>.
 # All rights reserved.  This is an open source license.  Contact
 # Ravenbrook for commercial licensing options.
 # 
diff --git a/mps/code/ll.gmk b/mps/code/ll.gmk
index fd91e62fe42..dc2595c511f 100644
--- a/mps/code/ll.gmk
+++ b/mps/code/ll.gmk
@@ -3,7 +3,7 @@
 # ll.gmk: GNUMAKEFILE FRAGMENT FOR CLANG/LLVM
 #
 # $Id$
-# Copyright (c) 2001-2013 Ravenbrook Limited.  See end of file for license.
+# Copyright (c) 2001-2014 Ravenbrook Limited.  See end of file for license.
 #
 # This file is included by platform makefiles that use the Clang/LLVM
 # compiler.  It defines the compiler-specific variables that the
@@ -12,11 +12,24 @@
 CC = clang
 CFLAGSDEBUG = -O -g3
 CFLAGSOPT = -O2 -g3
-CFLAGSCOMPILER :=  -Wall -Werror -Wpointer-arith \
-	-Wstrict-prototypes -Wmissing-prototypes \
-	-Winline -Waggregate-return -Wnested-externs \
-	-Wcast-qual -Wshadow # -Wstrict-aliasing=2
-CFLAGSCOMPILERSTRICT := -pedantic -Wno-extended-offsetof
+CFLAGSCOMPILER := \
+	-pedantic \
+	-Waggregate-return \
+	-Wall \
+	-Wcast-qual \
+	-Werror \
+	-Wextra \
+	-Winline \
+	-Wmissing-prototypes \
+	-Wnested-externs \
+	-Wno-extended-offsetof \
+	-Wpointer-arith \
+	-Wshadow \
+	-Wstrict-aliasing=2 \
+	-Wstrict-prototypes \
+	-Wunreachable-code \
+	-Wwrite-strings
+CFLAGSCOMPILERSTRICT :=
 
 # A different set of compiler flags for less strict compilation, for
 # instance when we need to #include a third-party header file that
@@ -38,7 +51,7 @@ endef
 
 # C. COPYRIGHT AND LICENSE
 #
-# Copyright (C) 2001-2013 Ravenbrook Limited <http://www.ravenbrook.com/>.
+# Copyright (C) 2001-2014 Ravenbrook Limited <http://www.ravenbrook.com/>.
 # All rights reserved.  This is an open source license.  Contact
 # Ravenbrook for commercial licensing options.
 # 
diff --git a/mps/code/mpm.h b/mps/code/mpm.h
index 46dcd74b880..da45d9aedd2 100644
--- a/mps/code/mpm.h
+++ b/mps/code/mpm.h
@@ -1008,9 +1008,6 @@ extern void StackProbe(Size depth);
  * STATISTIC_WRITE is inserted in WriteF arguments to output the values
  * of statistic fields.
  *
- * STATISTIC_BEGIN and STATISTIC_END can be used around a block of
- * statements.
- *
  * .statistic.whitehot: The implementation of STATISTIC for
  * non-statistical varieties passes the parameter to DISCARD to ensure
  * the parameter is syntactically an expression.  The parameter is
@@ -1022,16 +1019,12 @@ extern void StackProbe(Size depth);
 #define STATISTIC(gather) BEGIN (gather); END
 #define STATISTIC_STAT(gather) BEGIN gather; END
 #define STATISTIC_WRITE(format, arg) (format), (arg),
-#define STATISTIC_BEGIN BEGIN
-#define STATISTIC_END END
 
 #elif defined(STATISTICS_NONE)
 
 #define STATISTIC(gather) DISCARD(((gather), 0))
 #define STATISTIC_STAT DISCARD_STAT
 #define STATISTIC_WRITE(format, arg)
-#define STATISTIC_BEGIN BEGIN if (0) {
-#define STATISTIC_END } END
 
 #else /* !defined(STATISTICS) && !defined(STATISTICS_NONE) */
 
diff --git a/mps/code/mpmss.c b/mps/code/mpmss.c
index 547f3d746b6..9dd25574417 100644
--- a/mps/code/mpmss.c
+++ b/mps/code/mpmss.c
@@ -125,16 +125,9 @@ static size_t fixedSize(size_t i)
 }
 
 
-static mps_pool_debug_option_s bothOptions8 = {
-  /* .fence_template = */   (const void *)"postpost",
-  /* .fence_size = */       8,
-  /* .free_template = */    (const void *)"DEAD",
-  /* .free_size = */        4
-};
-
-static mps_pool_debug_option_s bothOptions16 = {
+static mps_pool_debug_option_s bothOptions = {
   /* .fence_template = */   (const void *)"postpostpostpost",
-  /* .fence_size = */       16,
+  /* .fence_size = */       MPS_PF_ALIGN,
   /* .free_template = */    (const void *)"DEAD",
   /* .free_size = */        4
 };
@@ -177,15 +170,12 @@ static void testInArena(mps_arena_t arena, mps_pool_debug_option_s *options)
 int main(int argc, char *argv[])
 {
   mps_arena_t arena;
-  mps_pool_debug_option_s *bothOptions;
-  
-  bothOptions = MPS_PF_ALIGN == 8 ? &bothOptions8 : &bothOptions16;
 
   testlib_init(argc, argv);
 
   die(mps_arena_create(&arena, mps_arena_class_vm(), testArenaSIZE),
       "mps_arena_create");
-  testInArena(arena, bothOptions);
+  testInArena(arena, &bothOptions);
   mps_arena_destroy(arena);
 
   die(mps_arena_create(&arena, mps_arena_class_vm(), smallArenaSIZE),
diff --git a/mps/code/mps.xcodeproj/project.pbxproj b/mps/code/mps.xcodeproj/project.pbxproj
index d7865d3d4a6..d9ce4fdd401 100644
--- a/mps/code/mps.xcodeproj/project.pbxproj
+++ b/mps/code/mps.xcodeproj/project.pbxproj
@@ -4609,29 +4609,24 @@
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				MACOSX_DEPLOYMENT_TARGET = 10.4;
-				OTHER_CFLAGS = (
-					"-pedantic",
-					"-Wall",
-					"-Wextra",
-					"-Wwrite-strings",
-					"-Wno-extended-offsetof",
-				);
 				SDKROOT = macosx;
 				SYMROOT = xc;
 				WARNING_CFLAGS = (
 					"-pedantic",
-					"-Wpointer-arith",
-					"-Wstrict-prototypes",
-					"-Wmissing-prototypes",
-					"-Winline",
 					"-Waggregate-return",
-					"-Wnested-externs",
-					"-Wcast-qual",
-					"-Wshadow",
 					"-Wall",
+					"-Wcast-qual",
 					"-Wextra",
-					"-Wwrite-strings",
+					"-Winline",
+					"-Wmissing-prototypes",
+					"-Wnested-externs",
 					"-Wno-extended-offsetof",
+					"-Wpointer-arith",
+					"-Wshadow",
+					"-Wstrict-aliasing=2",
+					"-Wstrict-prototypes",
+					"-Wunreachable-code",
+					"-Wwrite-strings",
 				);
 			};
 			name = RASH;
@@ -5053,29 +5048,24 @@
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				MACOSX_DEPLOYMENT_TARGET = 10.4;
 				ONLY_ACTIVE_ARCH = YES;
-				OTHER_CFLAGS = (
-					"-pedantic",
-					"-Wall",
-					"-Wextra",
-					"-Wwrite-strings",
-					"-Wno-extended-offsetof",
-				);
 				SDKROOT = macosx;
 				SYMROOT = xc;
 				WARNING_CFLAGS = (
 					"-pedantic",
-					"-Wpointer-arith",
-					"-Wstrict-prototypes",
-					"-Wmissing-prototypes",
-					"-Winline",
 					"-Waggregate-return",
-					"-Wnested-externs",
-					"-Wcast-qual",
-					"-Wshadow",
 					"-Wall",
+					"-Wcast-qual",
 					"-Wextra",
-					"-Wwrite-strings",
+					"-Winline",
+					"-Wmissing-prototypes",
+					"-Wnested-externs",
 					"-Wno-extended-offsetof",
+					"-Wpointer-arith",
+					"-Wshadow",
+					"-Wstrict-aliasing=2",
+					"-Wstrict-prototypes",
+					"-Wunreachable-code",
+					"-Wwrite-strings",
 				);
 			};
 			name = Debug;
@@ -5111,29 +5101,24 @@
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				MACOSX_DEPLOYMENT_TARGET = 10.4;
-				OTHER_CFLAGS = (
-					"-pedantic",
-					"-Wall",
-					"-Wextra",
-					"-Wwrite-strings",
-					"-Wno-extended-offsetof",
-				);
 				SDKROOT = macosx;
 				SYMROOT = xc;
 				WARNING_CFLAGS = (
 					"-pedantic",
-					"-Wpointer-arith",
-					"-Wstrict-prototypes",
-					"-Wmissing-prototypes",
-					"-Winline",
 					"-Waggregate-return",
-					"-Wnested-externs",
-					"-Wcast-qual",
-					"-Wshadow",
 					"-Wall",
+					"-Wcast-qual",
 					"-Wextra",
-					"-Wwrite-strings",
+					"-Winline",
+					"-Wmissing-prototypes",
+					"-Wnested-externs",
 					"-Wno-extended-offsetof",
+					"-Wpointer-arith",
+					"-Wshadow",
+					"-Wstrict-aliasing=2",
+					"-Wstrict-prototypes",
+					"-Wunreachable-code",
+					"-Wwrite-strings",
 				);
 			};
 			name = Release;
diff --git a/mps/code/poolamc.c b/mps/code/poolamc.c
index d7d8e0cbfd1..4e479266b7d 100644
--- a/mps/code/poolamc.c
+++ b/mps/code/poolamc.c
@@ -2242,18 +2242,18 @@ static void AMCTraceEnd(Pool pool, Trace trace)
   ti = trace->ti;
   AVER(TraceIdCheck(ti));
 
-  STATISTIC_BEGIN {
-      Count pRetMin = 100;
-      PageRetStruct *pr = &amc->pageretstruct[ti];
-      if(pr->pRet >= pRetMin) {
-        EVENT21(AMCTraceEnd, ArenaEpoch(pool->arena), (EventFU)trace->why,
-                ArenaAlign(pool->arena), AMCLargeSegPAGES, pRetMin, pr->pCond,
-                pr->pRet, pr->pCS, pr->pRS, pr->sCM, pr->pCM, pr->sRM, pr->pRM,
-                pr->pRM1, pr->pRMrr, pr->pRMr1, pr->sCL, pr->pCL, pr->sRL,
-                pr->pRL, pr->pRLr);
-      }
-      *pr = pageretstruct_Zero;
-  } STATISTIC_END;
+  STATISTIC_STAT ({
+    Count pRetMin = 100;
+    PageRetStruct *pr = &amc->pageretstruct[ti];
+    if(pr->pRet >= pRetMin) {
+      EVENT21(AMCTraceEnd, ArenaEpoch(pool->arena), (EventFU)trace->why,
+              ArenaAlign(pool->arena), AMCLargeSegPAGES, pRetMin, pr->pCond,
+              pr->pRet, pr->pCS, pr->pRS, pr->sCM, pr->pCM, pr->sRM, pr->pRM,
+              pr->pRM1, pr->pRMrr, pr->pRMr1, pr->sCL, pr->pCL, pr->sRL,
+              pr->pRL, pr->pRLr);
+    }
+    *pr = pageretstruct_Zero;
+  });
 }
 
 
diff --git a/mps/code/sacss.c b/mps/code/sacss.c
index bfb0725ed47..d2300de1898 100644
--- a/mps/code/sacss.c
+++ b/mps/code/sacss.c
@@ -140,41 +140,29 @@ static size_t randomSize8(size_t i)
 
 /* testInArena -- test all the pool classes in the given arena */
 
-static mps_pool_debug_option_s debugOptions8 = {
-  /* .fence_template = */   (const void *)"postpost",
-  /* .fence_size = */       8,
-  /* .free_template = */    (const void *)"DEAD",
-  /* .free_size = */        4
-};
-
-static mps_pool_debug_option_s debugOptions16 = {
+static mps_pool_debug_option_s debugOptions = {
   /* .fence_template = */   (const void *)"postpostpostpost",
-  /* .fence_size = */       16,
+  /* .fence_size = */       MPS_PF_ALIGN,
   /* .free_template = */    (const void *)"DEAD",
   /* .free_size = */        4
 };
 
-static mps_sac_classes_s classes8[4] = { {8, 1, 1}, {16, 1, 2}, {136, 9, 5},
-                                        {topClassSIZE, 9, 4} };
-
-static mps_sac_classes_s classes16[4] = { {16, 1, 1}, {32, 1, 2}, {144, 9, 5},
-                                        {topClassSIZE, 9, 4} };
+static mps_sac_classes_s classes[4] = {
+  {MPS_PF_ALIGN, 1, 1}, 
+  {MPS_PF_ALIGN * 2, 1, 2},
+  {128 + MPS_PF_ALIGN, 9, 5},
+  {topClassSIZE, 9, 4} 
+};
 
 static void testInArena(mps_arena_t arena)
 {
-  mps_pool_debug_option_s *debugOptions;
-  mps_sac_classes_s *classes;
-  
-  debugOptions = MPS_PF_ALIGN == 8 ? &debugOptions8 : &debugOptions16;
-  classes = MPS_PF_ALIGN == 8 ? classes8 : classes16;
-
   printf("MVFF\n\n");
   die(stress(mps_class_mvff(), classCOUNT, classes, randomSize8, arena,
              (size_t)65536, (size_t)32, (mps_align_t)MPS_PF_ALIGN, TRUE, TRUE, TRUE),
       "stress MVFF");
   printf("MV debug\n\n");
   die(stress(mps_class_mv_debug(), classCOUNT, classes, randomSize8, arena,
-             debugOptions, (size_t)65536, (size_t)32, (size_t)65536),
+             &debugOptions, (size_t)65536, (size_t)32, (size_t)65536),
       "stress MV debug");
   printf("MV\n\n");
   die(stress(mps_class_mv(), classCOUNT, classes, randomSize8, arena,
diff --git a/mps/code/trace.c b/mps/code/trace.c
index e77f93cd483..b394ed95e80 100644
--- a/mps/code/trace.c
+++ b/mps/code/trace.c
@@ -1,7 +1,7 @@
 /* trace.c: GENERIC TRACER IMPLEMENTATION
  *
  * $Id$
- * Copyright (c) 2001-2013 Ravenbrook Limited.
+ * Copyright (c) 2001-2014 Ravenbrook Limited.
  * See end of file for license.
  * Portions copyright (C) 2002 Global Graphics Software.
  *
@@ -1641,11 +1641,12 @@ Res TraceStart(Trace trace, double mortality, double finishingTime)
     } while (SegNext(&seg, arena, seg));
   }
 
-  STATISTIC_BEGIN {
+  STATISTIC_STAT ({
     /* @@ */
     /* Iterate over all chains, all GenDescs within a chain, */
     /* (and all PoolGens within a GenDesc).  */
-    Ring node, nextNode;
+    Ring node;
+    Ring nextNode;
     Index i;
     
     RING_FOR(node, &arena->chainRing, nextNode) {
@@ -1658,7 +1659,7 @@ Res TraceStart(Trace trace, double mortality, double finishingTime)
     
     /* Now do topgen GenDesc (and all PoolGens within it). */
     TraceStartPoolGen(NULL, &arena->topGen, TRUE, 0);
-  } STATISTIC_END;
+  });
 
   res = RootsIterate(ArenaGlobals(arena), rootGrey, (void *)trace);
   AVER(res == ResOK);
@@ -1900,7 +1901,7 @@ failStart:
 
 /* C. COPYRIGHT AND LICENSE
  *
- * Copyright (C) 2001-2013 Ravenbrook Limited
+ * Copyright (C) 2001-2014 Ravenbrook Limited
  * <http://www.ravenbrook.com/>.
  * All rights reserved.  This is an open source license.  Contact
  * Ravenbrook for commercial licensing options.
diff --git a/mps/code/zmess.c b/mps/code/zmess.c
index 2b6d533dfde..a97c10ea8f1 100644
--- a/mps/code/zmess.c
+++ b/mps/code/zmess.c
@@ -442,6 +442,9 @@ static void testscriptA(const char *script)
  *
  * TIMCA_remote returns a Bool, true for let "ControlAlloc succeed".
  */
+
+#ifdef TEST_CONTROLALLOC_FAILURE
+
 static const char *TIMCA_str = "";
 static int TIMCA_done = 0;
 static void TIMCA_setup(const char *string)
@@ -481,6 +484,8 @@ Bool TIMCA_remote(void)
   return succeed;
 }
 
+#endif  /* TEST_CONTROLALLOC_FAILURE */
+
 
 /* main -- runs various test scripts
  *
@@ -535,7 +540,8 @@ int main(int argc, char *argv[])
    *
    * See <design/message-gc#lifecycle>.
    */
-  if(0) {
+#if TEST_CONTROLALLOC_FAILURE
+  {
     /* ArenaCreate unable to pre-allocate: THESE SHOULD FAIL */
     /* manually edit if(0) -> if(1) to test these */
     if(0) {
@@ -562,6 +568,7 @@ int main(int argc, char *argv[])
     
     TIMCA_setup("");  /* must reset it! */
   }
+#endif
 
   printf("%s: Conclusion: Failed to find any defects.\n", argv[0]);
   return 0;
diff --git a/mps/example/scheme/scheme-advanced.c b/mps/example/scheme/scheme-advanced.c
index 22009cf2323..476b790f0a4 100644
--- a/mps/example/scheme/scheme-advanced.c
+++ b/mps/example/scheme/scheme-advanced.c
@@ -2011,8 +2011,6 @@ static obj_t entry_do(obj_t env, obj_t op_env, obj_t operator, obj_t operands)
       return result;
     }
   }
-  error("%s: unimplemented", operator->operator.name);
-  return obj_error;
 }
 
 
@@ -4007,7 +4005,6 @@ static mps_res_t obj_scan(mps_ss_t ss, mps_addr_t base, mps_addr_t limit)
         assert(0);
         fprintf(stderr, "Unexpected object on the heap\n");
         abort();
-        return MPS_RES_FAIL;
       }
     }
   } MPS_SCAN_END(ss);
@@ -4078,7 +4075,6 @@ static mps_addr_t obj_skip(mps_addr_t base)
     assert(0);
     fprintf(stderr, "Unexpected object on the heap\n");
     abort();
-    return NULL;
   }
   return base;
 }
diff --git a/mps/example/scheme/scheme-boehm.c b/mps/example/scheme/scheme-boehm.c
index 839f1a56fd3..8d039433bb4 100644
--- a/mps/example/scheme/scheme-boehm.c
+++ b/mps/example/scheme/scheme-boehm.c
@@ -1,6 +1,6 @@
 /* scheme.c -- SCHEME INTERPRETER EXAMPLE FOR THE MEMORY POOL SYSTEM
  *
- * Copyright (c) 2001-2013 Ravenbrook Limited.  See end of file for license.
+ * Copyright (c) 2001-2014 Ravenbrook Limited.  See end of file for license.
  * 
  * TO DO
  * - unbounded integers, other number types.
@@ -1728,8 +1728,6 @@ static obj_t entry_do(obj_t env, obj_t op_env, obj_t operator, obj_t operands)
       return result;
     }
   }
-  error("%s: unimplemented", operator->operator.name);
-  return obj_error;
 }
 
 
@@ -3638,7 +3636,7 @@ int main(int argc, char *argv[])
 
 /* C. COPYRIGHT AND LICENSE
  *
- * Copyright (C) 2001-2013 Ravenbrook Limited <http://www.ravenbrook.com/>.
+ * Copyright (C) 2001-2014 Ravenbrook Limited <http://www.ravenbrook.com/>.
  * All rights reserved.  This is an open source license.  Contact
  * Ravenbrook for commercial licensing options.
  * 
diff --git a/mps/example/scheme/scheme-malloc.c b/mps/example/scheme/scheme-malloc.c
index 799e7db66cf..1333ce73aef 100644
--- a/mps/example/scheme/scheme-malloc.c
+++ b/mps/example/scheme/scheme-malloc.c
@@ -1,6 +1,6 @@
 /* scheme.c -- SCHEME INTERPRETER EXAMPLE FOR THE MEMORY POOL SYSTEM
  *
- * Copyright (c) 2001-2013 Ravenbrook Limited.  See end of file for license.
+ * Copyright (c) 2001-2014 Ravenbrook Limited.  See end of file for license.
  * 
  * TO DO
  * - unbounded integers, other number types.
@@ -1728,8 +1728,6 @@ static obj_t entry_do(obj_t env, obj_t op_env, obj_t operator, obj_t operands)
       return result;
     }
   }
-  error("%s: unimplemented", operator->operator.name);
-  return obj_error;
 }
 
 
@@ -3635,7 +3633,7 @@ int main(int argc, char *argv[])
 
 /* C. COPYRIGHT AND LICENSE
  *
- * Copyright (C) 2001-2013 Ravenbrook Limited <http://www.ravenbrook.com/>.
+ * Copyright (C) 2001-2014 Ravenbrook Limited <http://www.ravenbrook.com/>.
  * All rights reserved.  This is an open source license.  Contact
  * Ravenbrook for commercial licensing options.
  * 
diff --git a/mps/example/scheme/scheme.c b/mps/example/scheme/scheme.c
index 4b2b36797c5..8a8dcf48ed7 100644
--- a/mps/example/scheme/scheme.c
+++ b/mps/example/scheme/scheme.c
@@ -2037,8 +2037,6 @@ static obj_t entry_do(obj_t env, obj_t op_env, obj_t operator, obj_t operands)
       return result;
     }
   }
-  error("%s: unimplemented", operator->operator.name);
-  return obj_error;
 }
 
 
@@ -3994,7 +3992,6 @@ static mps_res_t obj_scan(mps_ss_t ss, mps_addr_t base, mps_addr_t limit)
         assert(0);
         fprintf(stderr, "Unexpected object on the heap\n");
         abort();
-        return MPS_RES_FAIL;
       }
     }
   } MPS_SCAN_END(ss);
@@ -4071,7 +4068,6 @@ static mps_addr_t obj_skip(mps_addr_t base)
     assert(0);
     fprintf(stderr, "Unexpected object on the heap\n");
     abort();
-    return NULL;
   }
   return base;
 }