diff --git a/selfhost/cmd/w6c/main.combined.ww b/selfhost/cmd/w6c/main.combined.ww
index 774b9e84..b9d1ba84 100644
--- a/selfhost/cmd/w6c/main.combined.ww
+++ b/selfhost/cmd/w6c/main.combined.ww
@@ -7346,6 +7346,27 @@ fn resolvewalk(c: *checker, n: *node) void = {
 		return;
 	};
 
+	// #53: lexical block. Push a child scope so locals introduced by
+	// inner-block lets (and the `let` install at the tail of this fn) go
+	// out of scope at block exit. Without this, a deeply nested
+	// `let i: u64 = 0u64;` survived to shadow a same-named outer
+	// `let i: i32 = 1;` for the whole fn body, and exprtype handed
+	// stale primitive types to checkletassign — silent miscompile
+	// becomes a false-positive on the next driver (`wwdump_ww -r`
+	// flagged the u64→i32 pair in selfhost/cmd/ww/enumeratedir).
+	// Mirrors cstage cstmt N_BLOCK at cmd/wcc/check.c:1559-1566.
+	if (k == nkind.N_BLOCK) {
+		let outer: *scope = c.cur;
+		c.cur = newscope(c.a, outer);
+		let m: *node = n.list;
+		for (m != nil) {
+			resolvewalk(c, m);
+			m = m.next;
+		};
+		c.cur = outer;
+		return;
+	};
+
 	if (k == nkind.N_DOT) {
 		// Walk only the base; the .field name is a member, not a
 		// free identifier.
@@ -7383,14 +7404,12 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	// are installed in installdecl, so this duplicate install at
 	// the file scope just no-ops (scopedefine returns nil on dup).
 	//
-	// TODO(#11): cstage check.c (post-#32) errors `let '%s' redeclared
-	// in same scope` here. Wwstage resolvewalk has no per-block scope
-	// (see resolvefnbody's docstring) so a same-fn-body
-	// `let a=1; { let a=2; };` would falsely trip if we guarded
-	// scopedefine's nil return today. Silent-accept matches the
-	// deferred-check design until #11 adds per-block scoping; see
-	// test/wcc/708 and test/wcc/696 for the same cstage-only neg-case
-	// precedent.
+	// Cross-block `let a; { let a; };` no longer trips dup-silence
+	// since #53 added N_BLOCK push/pop above — the inner `a` lands in
+	// the inner block's scope. Same-scope dup `let a=1; let a=2;`
+	// still silent-accepts here; promoting that to an error stays
+	// queued behind #11 (test/wcc/708 + test/wcc/696 are the cstage-
+	// only neg-case precedent).
 	if (k == nkind.N_LET) {
 		let nm: str = n.str;
 		if (nm.len > 0) {
diff --git a/selfhost/cmd/wcc/check.ww b/selfhost/cmd/wcc/check.ww
index 38465d5b..4005fe75 100644
--- a/selfhost/cmd/wcc/check.ww
+++ b/selfhost/cmd/wcc/check.ww
@@ -352,6 +352,27 @@ fn resolvewalk(c: *checker, n: *node) void = {
 		return;
 	};
 
+	// #53: lexical block. Push a child scope so locals introduced by
+	// inner-block lets (and the `let` install at the tail of this fn) go
+	// out of scope at block exit. Without this, a deeply nested
+	// `let i: u64 = 0u64;` survived to shadow a same-named outer
+	// `let i: i32 = 1;` for the whole fn body, and exprtype handed
+	// stale primitive types to checkletassign — silent miscompile
+	// becomes a false-positive on the next driver (`wwdump_ww -r`
+	// flagged the u64→i32 pair in selfhost/cmd/ww/enumeratedir).
+	// Mirrors cstage cstmt N_BLOCK at cmd/wcc/check.c:1559-1566.
+	if (k == nkind.N_BLOCK) {
+		let outer: *scope = c.cur;
+		c.cur = newscope(c.a, outer);
+		let m: *node = n.list;
+		for (m != nil) {
+			resolvewalk(c, m);
+			m = m.next;
+		};
+		c.cur = outer;
+		return;
+	};
+
 	if (k == nkind.N_DOT) {
 		// Walk only the base; the .field name is a member, not a
 		// free identifier.
@@ -389,14 +410,12 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	// are installed in installdecl, so this duplicate install at
 	// the file scope just no-ops (scopedefine returns nil on dup).
 	//
-	// TODO(#11): cstage check.c (post-#32) errors `let '%s' redeclared
-	// in same scope` here. Wwstage resolvewalk has no per-block scope
-	// (see resolvefnbody's docstring) so a same-fn-body
-	// `let a=1; { let a=2; };` would falsely trip if we guarded
-	// scopedefine's nil return today. Silent-accept matches the
-	// deferred-check design until #11 adds per-block scoping; see
-	// test/wcc/708 and test/wcc/696 for the same cstage-only neg-case
-	// precedent.
+	// Cross-block `let a; { let a; };` no longer trips dup-silence
+	// since #53 added N_BLOCK push/pop above — the inner `a` lands in
+	// the inner block's scope. Same-scope dup `let a=1; let a=2;`
+	// still silent-accepts here; promoting that to an error stays
+	// queued behind #11 (test/wcc/708 + test/wcc/696 are the cstage-
+	// only neg-case precedent).
 	if (k == nkind.N_LET) {
 		let nm: str = n.str;
 		if (nm.len > 0) {
diff --git a/selfhost/cmd/wwdump/main.combined.ww b/selfhost/cmd/wwdump/main.combined.ww
index 7b36abb0..28d502c3 100644
--- a/selfhost/cmd/wwdump/main.combined.ww
+++ b/selfhost/cmd/wwdump/main.combined.ww
@@ -7346,6 +7346,27 @@ fn resolvewalk(c: *checker, n: *node) void = {
 		return;
 	};
 
+	// #53: lexical block. Push a child scope so locals introduced by
+	// inner-block lets (and the `let` install at the tail of this fn) go
+	// out of scope at block exit. Without this, a deeply nested
+	// `let i: u64 = 0u64;` survived to shadow a same-named outer
+	// `let i: i32 = 1;` for the whole fn body, and exprtype handed
+	// stale primitive types to checkletassign — silent miscompile
+	// becomes a false-positive on the next driver (`wwdump_ww -r`
+	// flagged the u64→i32 pair in selfhost/cmd/ww/enumeratedir).
+	// Mirrors cstage cstmt N_BLOCK at cmd/wcc/check.c:1559-1566.
+	if (k == nkind.N_BLOCK) {
+		let outer: *scope = c.cur;
+		c.cur = newscope(c.a, outer);
+		let m: *node = n.list;
+		for (m != nil) {
+			resolvewalk(c, m);
+			m = m.next;
+		};
+		c.cur = outer;
+		return;
+	};
+
 	if (k == nkind.N_DOT) {
 		// Walk only the base; the .field name is a member, not a
 		// free identifier.
@@ -7383,14 +7404,12 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	// are installed in installdecl, so this duplicate install at
 	// the file scope just no-ops (scopedefine returns nil on dup).
 	//
-	// TODO(#11): cstage check.c (post-#32) errors `let '%s' redeclared
-	// in same scope` here. Wwstage resolvewalk has no per-block scope
-	// (see resolvefnbody's docstring) so a same-fn-body
-	// `let a=1; { let a=2; };` would falsely trip if we guarded
-	// scopedefine's nil return today. Silent-accept matches the
-	// deferred-check design until #11 adds per-block scoping; see
-	// test/wcc/708 and test/wcc/696 for the same cstage-only neg-case
-	// precedent.
+	// Cross-block `let a; { let a; };` no longer trips dup-silence
+	// since #53 added N_BLOCK push/pop above — the inner `a` lands in
+	// the inner block's scope. Same-scope dup `let a=1; let a=2;`
+	// still silent-accepts here; promoting that to an error stays
+	// queued behind #11 (test/wcc/708 + test/wcc/696 are the cstage-
+	// only neg-case precedent).
 	if (k == nkind.N_LET) {
 		let nm: str = n.str;
 		if (nm.len > 0) {