diff --git a/imemo.c b/imemo.c
index 9154f6bc6ac280..3814fbd4538d85 100644
--- a/imemo.c
+++ b/imemo.c
@@ -645,11 +645,7 @@ rb_imemo_free(VALUE obj)
       case imemo_callinfo:{
         const struct rb_callinfo *ci = ((const struct rb_callinfo *)obj);
 
-        if (ci->kwarg) {
-            if (RUBY_ATOMIC_FETCH_SUB(((struct rb_callinfo_kwarg *)ci->kwarg)->references, 1) == 1) {
-                ruby_xfree_sized((void *)ci->kwarg, rb_callinfo_kwarg_bytes(ci->kwarg->keyword_len));
-            }
-        }
+        rb_callinfo_kwarg_release((struct rb_callinfo_kwarg *)ci->kwarg);
         RB_DEBUG_COUNTER_INC(obj_imemo_callinfo);
 
         break;
diff --git a/prism/prism.c b/prism/prism.c
index e3137d3167e7db..d997c63d166e06 100644
--- a/prism/prism.c
+++ b/prism/prism.c
@@ -15290,6 +15290,12 @@ parse_block(pm_parser_t *parser, uint16_t depth) {
             statements = UP(parse_statements(parser, PM_CONTEXT_BLOCK_BRACES, (uint16_t) (depth + 1)));
         }
 
+        /* Pop before consuming the closing `}` so the following token (e.g. a
+         * `do`) is lexed in the enclosing context rather than as a block
+         * belonging to this block's interior. Otherwise a `do` block would
+         * wrongly bind to a command whose argument ends in a brace block, as in
+         * `foo(m a { } do end)`. */
+        pm_accepts_block_stack_pop(parser);
         expect1_opening(parser, PM_TOKEN_BRACE_RIGHT, PM_ERR_BLOCK_TERM_BRACE, &opening);
     } else {
         if (!match1(parser, PM_TOKEN_KEYWORD_END)) {
@@ -15305,6 +15311,8 @@ parse_block(pm_parser_t *parser, uint16_t depth) {
             }
         }
 
+        /* As with the brace case above, pop before consuming `end`. */
+        pm_accepts_block_stack_pop(parser);
         expect1_opening(parser, PM_TOKEN_KEYWORD_END, PM_ERR_BLOCK_TERM_END, &opening);
     }
 
@@ -15313,7 +15321,6 @@ parse_block(pm_parser_t *parser, uint16_t depth) {
     pm_node_t *parameters = parse_blocklike_parameters(parser, UP(block_parameters), &opening, &parser->previous);
 
     pm_parser_scope_pop(parser);
-    pm_accepts_block_stack_pop(parser);
 
     return pm_block_node_create(parser, &locals, &opening, parameters, statements, &parser->previous);
 }
diff --git a/prism_compile.c b/prism_compile.c
index 353e018d878493..e70477a51c786e 100644
--- a/prism_compile.c
+++ b/prism_compile.c
@@ -3887,6 +3887,8 @@ pm_compile_call(rb_iseq_t *iseq, const pm_call_node_t *call_node, LINK_ANCHOR *c
             ELEM_INSERT_NEXT(opt_new_prelude, &new_insn_body(iseq, location.line, location.node_id, BIN(putnil), 0)->link);
         }
 
+        rb_callinfo_kwarg_retain(kw_arg);
+
         // Jump unless the receiver uses the "basic" implementation of "new"
         VALUE ci;
         if (flags & VM_CALL_FORWARDING) {
@@ -3909,6 +3911,8 @@ pm_compile_call(rb_iseq_t *iseq, const pm_call_node_t *call_node, LINK_ANCHOR *c
 
         PUSH_LABEL(ret, not_basic_new_finish);
         PUSH_INSN(ret, location, pop);
+
+        rb_callinfo_kwarg_release(kw_arg);
     }
     else {
         PUSH_SEND_R(ret, location, method_id, INT2FIX(orig_argc), block_iseq, INT2FIX(flags), kw_arg);
diff --git a/test/prism/errors/do_block_after_command_block.txt b/test/prism/errors/do_block_after_command_block.txt
new file mode 100644
index 00000000000000..0989695af0c130
--- /dev/null
+++ b/test/prism/errors/do_block_after_command_block.txt
@@ -0,0 +1,14 @@
+foo(m a { } do end)
+            ^~ unexpected 'do'; expected a `)` to close the arguments
+            ^~ unexpected 'do', expecting end-of-input
+            ^~ unexpected 'do', ignoring it
+               ^~~ unexpected 'end', ignoring it
+                  ^ unexpected ')', ignoring it
+
+foo(m a.b { } do end)
+              ^~ unexpected 'do'; expected a `)` to close the arguments
+              ^~ unexpected 'do', expecting end-of-input
+              ^~ unexpected 'do', ignoring it
+                 ^~~ unexpected 'end', ignoring it
+                    ^ unexpected ')', ignoring it
+
diff --git a/vm_callinfo.h b/vm_callinfo.h
index 9a6c69deaee35d..0ff0d89d1a5617 100644
--- a/vm_callinfo.h
+++ b/vm_callinfo.h
@@ -61,6 +61,20 @@ rb_callinfo_kwarg_bytes(int keyword_len)
         rb_eRuntimeError);
 }
 
+static inline void
+rb_callinfo_kwarg_retain(struct rb_callinfo_kwarg *kwarg)
+{
+    if (kwarg) RUBY_ATOMIC_INC(kwarg->references);
+}
+
+static inline void
+rb_callinfo_kwarg_release(struct rb_callinfo_kwarg *kwarg)
+{
+    if (kwarg && RUBY_ATOMIC_FETCH_SUB(kwarg->references, 1) == 1) {
+        ruby_xfree_sized(kwarg, rb_callinfo_kwarg_bytes(kwarg->keyword_len));
+    }
+}
+
 // imemo_callinfo
 struct rb_callinfo {
     VALUE flags;