diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 594283168c9..8e66083a390 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -817,7 +817,6 @@ fn test_unstable_options_tracking_hash() {
     tracked!(split_lto_unit, Some(true));
     tracked!(src_hash_algorithm, Some(SourceFileHashAlgorithm::Sha1));
     tracked!(stack_protector, StackProtector::All);
-    tracked!(symbol_mangling_version, Some(SymbolManglingVersion::V0));
     tracked!(teach, true);
     tracked!(thinlto, Some(true));
     tracked!(thir_unsafeck, true);
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index a8ebab4ae33..715a7f9cb63 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -2674,28 +2674,19 @@ pub fn build_session_options(
         );
     }
 
-    // Handle both `-Z symbol-mangling-version` and `-C symbol-mangling-version`; the latter takes
-    // precedence.
-    match (cg.symbol_mangling_version, unstable_opts.symbol_mangling_version) {
-        (Some(smv_c), Some(smv_z)) if smv_c != smv_z => {
-            handler.early_error(
-                "incompatible values passed for `-C symbol-mangling-version` \
-                and `-Z symbol-mangling-version`",
-            );
+    // Check for unstable values of `-C symbol-mangling-version`.
+    // This is what prevents them from being used on stable compilers.
+    match cg.symbol_mangling_version {
+        // Stable values:
+        None | Some(SymbolManglingVersion::V0) => {}
+        // Unstable values:
+        Some(SymbolManglingVersion::Legacy) => {
+            if !unstable_opts.unstable_options {
+                handler.early_error(
+                    "`-C symbol-mangling-version=legacy` requires `-Z unstable-options`",
+                );
+            }
         }
-        (Some(SymbolManglingVersion::V0), _) => {}
-        (Some(_), _) if !unstable_opts.unstable_options => {
-            handler
-                .early_error("`-C symbol-mangling-version=legacy` requires `-Z unstable-options`");
-        }
-        (None, None) => {}
-        (None, smv) => {
-            handler.early_warn(
-                "`-Z symbol-mangling-version` is deprecated; use `-C symbol-mangling-version`",
-            );
-            cg.symbol_mangling_version = smv;
-        }
-        _ => {}
     }
 
     // Check for unstable values of `-C instrument-coverage`.
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 25a4547362c..7510a41485a 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1821,9 +1821,6 @@ written to standard error output)"),
         "control if mem::uninitialized and mem::zeroed panic on more UB"),
     strip: Strip = (Strip::None, parse_strip, [UNTRACKED],
         "tell the linker which information to strip (`none` (default), `debuginfo` or `symbols`)"),
-    symbol_mangling_version: Option<SymbolManglingVersion> = (None,
-        parse_symbol_mangling_version, [TRACKED],
-        "which mangling version to use for symbol names ('legacy' (default) or 'v0')"),
     #[rustc_lint_opt_deny_field_access("use `Session::teach` instead of this field")]
     teach: bool = (false, parse_bool, [TRACKED],
         "show extended diagnostic help (default: no)"),
diff --git a/src/tools/tidy/src/ui_tests.rs b/src/tools/tidy/src/ui_tests.rs
index dcf218bc189..7e24793adee 100644
--- a/src/tools/tidy/src/ui_tests.rs
+++ b/src/tools/tidy/src/ui_tests.rs
@@ -11,7 +11,7 @@ use std::path::{Path, PathBuf};
 const ENTRY_LIMIT: usize = 900;
 // FIXME: The following limits should be reduced eventually.
 const ISSUES_ENTRY_LIMIT: usize = 1854;
-const ROOT_ENTRY_LIMIT: usize = 866;
+const ROOT_ENTRY_LIMIT: usize = 867;
 
 const EXPECTED_TEST_FILE_EXTENSIONS: &[&str] = &[
     "rs",     // test source files
diff --git a/tests/run-make/crate-hash-rustc-version/Makefile b/tests/run-make/crate-hash-rustc-version/Makefile
index f1d2a360410..6bf504bf01b 100644
--- a/tests/run-make/crate-hash-rustc-version/Makefile
+++ b/tests/run-make/crate-hash-rustc-version/Makefile
@@ -4,7 +4,7 @@ include ../tools.mk
 # Ensure that crates compiled with different rustc versions cannot
 # be dynamically linked.
 
-FLAGS := -Cprefer-dynamic -Zsymbol-mangling-version=v0
+FLAGS := -Cprefer-dynamic -Csymbol-mangling-version=v0
 UNAME := $(shell uname)
 ifeq ($(UNAME),Linux)
   EXT=".so"
diff --git a/tests/ui/symbol-mangling-version/bad-value.bad.stderr b/tests/ui/symbol-mangling-version/bad-value.bad.stderr
new file mode 100644
index 00000000000..c36c73c6069
--- /dev/null
+++ b/tests/ui/symbol-mangling-version/bad-value.bad.stderr
@@ -0,0 +1,2 @@
+error: incorrect value `bad-value` for codegen option `symbol-mangling-version` - either `legacy` or `v0` (RFC 2603) was expected
+
diff --git a/tests/ui/symbol-mangling-version/bad-value.blank.stderr b/tests/ui/symbol-mangling-version/bad-value.blank.stderr
new file mode 100644
index 00000000000..0e70af5b8ff
--- /dev/null
+++ b/tests/ui/symbol-mangling-version/bad-value.blank.stderr
@@ -0,0 +1,2 @@
+error: incorrect value `` for codegen option `symbol-mangling-version` - either `legacy` or `v0` (RFC 2603) was expected
+
diff --git a/tests/ui/symbol-mangling-version/bad-value.no-value.stderr b/tests/ui/symbol-mangling-version/bad-value.no-value.stderr
new file mode 100644
index 00000000000..77013b72b6c
--- /dev/null
+++ b/tests/ui/symbol-mangling-version/bad-value.no-value.stderr
@@ -0,0 +1,2 @@
+error: codegen option `symbol-mangling-version` requires either `legacy` or `v0` (RFC 2603) (C symbol-mangling-version=<value>)
+
diff --git a/tests/ui/symbol-mangling-version/bad-value.rs b/tests/ui/symbol-mangling-version/bad-value.rs
new file mode 100644
index 00000000000..7623857d49e
--- /dev/null
+++ b/tests/ui/symbol-mangling-version/bad-value.rs
@@ -0,0 +1,6 @@
+// revisions: no-value blank bad
+// [no-value] compile-flags: -Csymbol-mangling-version
+// [blank] compile-flags: -Csymbol-mangling-version=
+// [bad] compile-flags: -Csymbol-mangling-version=bad-value
+
+fn main() {}
diff --git a/tests/ui/symbol-mangling-version/stable.rs b/tests/ui/symbol-mangling-version/stable.rs
new file mode 100644
index 00000000000..dac9bb18d1c
--- /dev/null
+++ b/tests/ui/symbol-mangling-version/stable.rs
@@ -0,0 +1,5 @@
+// check-pass
+// revisions: v0
+// [v0] compile-flags: -Csymbol-mangling-version=v0
+
+fn main() {}
diff --git a/tests/ui/symbol-mangling-version/unstable.legacy.stderr b/tests/ui/symbol-mangling-version/unstable.legacy.stderr
new file mode 100644
index 00000000000..c5b359b41bd
--- /dev/null
+++ b/tests/ui/symbol-mangling-version/unstable.legacy.stderr
@@ -0,0 +1,2 @@
+error: `-C symbol-mangling-version=legacy` requires `-Z unstable-options`
+
diff --git a/tests/ui/symbol-mangling-version/unstable.rs b/tests/ui/symbol-mangling-version/unstable.rs
new file mode 100644
index 00000000000..df87a39cdfb
--- /dev/null
+++ b/tests/ui/symbol-mangling-version/unstable.rs
@@ -0,0 +1,6 @@
+// revisions: legacy legacy-ok
+// [legacy] compile-flags: -Csymbol-mangling-version=legacy
+// [legacy-ok] check-pass
+// [legacy-ok] compile-flags: -Zunstable-options -Csymbol-mangling-version=legacy
+
+fn main() {}