diff --git a/release/c/wuffs-unsupported-snapshot.c b/release/c/wuffs-unsupported-snapshot.c
index 400895e72..5d9ca4a23 100644
--- a/release/c/wuffs-unsupported-snapshot.c
+++ b/release/c/wuffs-unsupported-snapshot.c
@@ -40795,14 +40795,12 @@ wuffs_png__decoder__do_decode_image_config(
       status = wuffs_base__make_status(wuffs_base__note__metadata_reported);
       goto ok;
     }
+    label__1__continue:;
     while (true) {
-      while (((uint64_t)(io2_a_src - iop_a_src)) < 8) {
-        if (a_src && a_src->meta.closed) {
-          status = wuffs_base__make_status(wuffs_png__error__bad_chunk);
-          goto exit;
-        }
+      if (((uint64_t)(io2_a_src - iop_a_src)) < 8) {
         status = wuffs_base__make_status(wuffs_base__suspension__short_read);
         WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(8);
+        goto label__1__continue;
       }
       self->private_impl.f_chunk_length = wuffs_base__peek_u32be__no_bounds_check(iop_a_src);
       self->private_impl.f_chunk_type = ((uint32_t)((wuffs_base__peek_u64le__no_bounds_check(iop_a_src) >> 32)));
@@ -43201,13 +43199,10 @@ wuffs_png__decoder__skip_frame(
     self->private_impl.f_chunk_type_array[3] = 0;
     label__0__continue:;
     while (true) {
-      while (((uint64_t)(io2_a_src - iop_a_src)) < 8) {
-        if (a_src && a_src->meta.closed) {
-          status = wuffs_base__make_status(wuffs_png__error__bad_chunk);
-          goto exit;
-        }
+      if (((uint64_t)(io2_a_src - iop_a_src)) < 8) {
         status = wuffs_base__make_status(wuffs_base__suspension__short_read);
         WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(1);
+        goto label__0__continue;
       }
       self->private_impl.f_chunk_length = wuffs_base__peek_u32be__no_bounds_check(iop_a_src);
       self->private_impl.f_chunk_type = ((uint32_t)((wuffs_base__peek_u64le__no_bounds_check(iop_a_src) >> 32)));
@@ -43446,14 +43441,12 @@ wuffs_png__decoder__do_decode_frame(
         goto suspend;
       }
     }
+    label__0__continue:;
     while (true) {
-      while (((uint64_t)(io2_a_src - iop_a_src)) < 8) {
-        if (a_src && a_src->meta.closed) {
-          status = wuffs_base__make_status(wuffs_png__error__bad_chunk);
-          goto exit;
-        }
+      if (((uint64_t)(io2_a_src - iop_a_src)) < 8) {
         status = wuffs_base__make_status(wuffs_base__suspension__short_read);
         WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(2);
+        goto label__0__continue;
       }
       self->private_impl.f_chunk_length = wuffs_base__peek_u32be__no_bounds_check(iop_a_src);
       self->private_impl.f_chunk_type = ((uint32_t)((wuffs_base__peek_u64le__no_bounds_check(iop_a_src) >> 32)));
@@ -43588,14 +43581,12 @@ wuffs_png__decoder__do_decode_frame(
               wuffs_png__decoder__filter_and_swizzle(self, a_dst, wuffs_base__slice_u8__subslice_j(a_workbuf, self->private_impl.f_workbuf_wi));
             }
             if (v_status.repr == wuffs_base__suspension__short_read) {
-              while (true) {
-                status = wuffs_base__make_status(wuffs_base__suspension__short_read);
-                WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(6);
-              }
+              status = wuffs_base__make_status(wuffs_png__error__truncated_input);
+              goto exit;
             }
           }
           status = v_status;
-          WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(7);
+          WUFFS_BASE__COROUTINE_SUSPENSION_POINT_MAYBE_SUSPEND(6);
         }
         label__1__break:;
         v_status = wuffs_png__decoder__filter_and_swizzle(self, a_dst, a_workbuf);
diff --git a/std/png/decode_png.wuffs b/std/png/decode_png.wuffs
index d330a44cb..33dd22791 100644
--- a/std/png/decode_png.wuffs
+++ b/std/png/decode_png.wuffs
@@ -241,14 +241,10 @@ pri func decoder.do_decode_image_config?(dst: nptr base.image_config, src: base.
 	// IDAT chunk breaks the loop. The only other possible critical chunk is a
 	// PLTE chunk. We verify PLTE checksums here but ignore other checksums.
 	while true {
-		while args.src.length() < 8,
-			post args.src.length() >= 8,
-		{
-			if args.src.is_closed() {
-				return "#bad chunk"
-			}
+		if args.src.length() < 8 {
 			yield? base."$short read"
-		} endwhile
+			continue
+		}
 
 		this.chunk_length = args.src.peek_u32be()
 		this.chunk_type = (args.src.peek_u64le() >> 32) as base.u32
@@ -1053,14 +1049,10 @@ pri func decoder.skip_frame?(src: base.io_reader) {
 	this.chunk_type_array[3] = 0
 
 	while true {
-		while args.src.length() < 8,
-			post args.src.length() >= 8,
-		{
-			if args.src.is_closed() {
-				return "#bad chunk"
-			}
+		if args.src.length() < 8 {
 			yield? base."$short read"
-		} endwhile
+			continue
+		}
 
 		this.chunk_length = args.src.peek_u32be()
 		this.chunk_type = (args.src.peek_u64le() >> 32) as base.u32
@@ -1141,14 +1133,10 @@ pri func decoder.do_decode_frame?(dst: ptr base.pixel_buffer, src: base.io_reade
 	}
 
 	while true {
-		while args.src.length() < 8,
-			post args.src.length() >= 8,
-		{
-			if args.src.is_closed() {
-				return "#bad chunk"
-			}
+		if args.src.length() < 8 {
 			yield? base."$short read"
-		} endwhile
+			continue
+		}
 
 		this.chunk_length = args.src.peek_u32be()
 		this.chunk_type = (args.src.peek_u64le() >> 32) as base.u32
@@ -1234,9 +1222,8 @@ pri func decoder.do_decode_frame?(dst: ptr base.pixel_buffer, src: base.io_reade
 					break
 				} else if status.is_error() or
 					((status == base."$short read") and args.src.is_closed()) {
-					// The input was truncated or invalid. Produce whatever
-					// pixels we can and then, if truncated, generate "$short
-					// read" forever.
+					// The input was invalid or truncated. Produce whatever
+					// pixels we can.
 					if this.workbuf_wi <= args.workbuf.length() {
 						// This might return "#internal error: inconsistent
 						// workbuf length" because of the ".. this.workbuf_wi".
@@ -1244,9 +1231,7 @@ pri func decoder.do_decode_frame?(dst: ptr base.pixel_buffer, src: base.io_reade
 						this.filter_and_swizzle!(dst: args.dst, workbuf: args.workbuf[.. this.workbuf_wi])
 					}
 					if status == base."$short read" {
-						while true {
-							yield? base."$short read"
-						} endwhile
+						return "#truncated input"
 					}
 				}
 				yield? status