diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/borrowed_from_one_path.exp b/third_party/move/move-compiler-v2/tests/ability-transform/borrowed_from_one_path.exp
index bf7ce3ca16be6d..ae4da36466455f 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/borrowed_from_one_path.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/borrowed_from_one_path.exp
@@ -71,6 +71,50 @@ fun m::f($t0: u8, $t1: &vector<u64>): u64 {
  14: return $t2
 }
 
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+fun m::f($t0: u8, $t1: &vector<u64>): u64 {
+     var $t2: u64
+     var $t3: &vector<u64>
+     var $t4: bool
+     var $t5: u8
+     var $t6: &m::R
+     var $t7: address
+     var $t8: &u64
+     var $t9: u64
+     # live vars: $t0, $t1
+  0: $t5 := 0
+     # live vars: $t0, $t1, $t5
+  1: $t4 := ==($t0, $t5)
+     # live vars: $t1, $t4
+  2: if ($t4) goto 3 else goto 8
+     # live vars: $t1
+  3: label L0
+     # live vars:
+  4: $t7 := 0x1
+     # live vars: $t7
+  5: $t6 := borrow_global<m::R>($t7)
+     # live vars: $t6
+  6: $t3 := borrow_field<m::R>.data($t6)
+     # live vars: $t3
+  7: goto 10
+     # live vars: $t1
+  8: label L1
+     # live vars: $t1
+  9: $t3 := infer($t1)
+     # live vars: $t3
+ 10: label L2
+     # live vars: $t3
+ 11: $t9 := 0
+     # live vars: $t3, $t9
+ 12: $t8 := vector::borrow<u64>($t3, $t9)
+     # live vars: $t8
+ 13: $t2 := read_ref($t8)
+     # live vars: $t2
+ 14: return $t2
+}
+
 ============ after ReferenceSafetyProcessor: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/by_reference.exp b/third_party/move/move-compiler-v2/tests/ability-transform/by_reference.exp
index 365b42d7f3f620..bff0906be42e10 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/by_reference.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/by_reference.exp
@@ -333,6 +333,216 @@ fun <SELF>_0::check() {
  84: return ()
 }
 
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+fun <SELF>_0::check() {
+     var $t0: bool
+     var $t1: u64
+     var $t2: bool
+     var $t3: u64
+     var $t4: bool
+     var $t5: u64
+     var $t6: &u64
+     var $t7: u64
+     var $t8: u64
+     var $t9: u64
+     var $t10: bool
+     var $t11: vector<u8>
+     var $t12: &vector<u8>
+     var $t13: vector<u8>
+     var $t14: vector<u8>
+     var $t15: u64
+     var $t16: &mut u64
+     var $t17: u64
+     var $t18: u64
+     var $t19: &mut vector<u8>
+     var $t20: vector<u8>
+     var $t21: vector<u8>
+     var $t22: bool
+     var $t23: u64
+     var $t24: u64
+     var $t25: u64
+     var $t26: bool
+     var $t27: vector<u8>
+     var $t28: vector<u8>
+     var $t29: u64
+     var $t30: bool
+     var $t31: u64
+     var $t32: bool
+     var $t33: u64
+     # live vars:
+  0: $t0 := true
+     # live vars: $t0
+  1: if ($t0) goto 2 else goto 4
+     # live vars:
+  2: label L0
+     # live vars:
+  3: goto 7
+     # live vars:
+  4: label L1
+     # live vars:
+  5: $t1 := 42
+     # live vars: $t1
+  6: abort($t1)
+     # live vars:
+  7: label L2
+     # live vars:
+  8: $t2 := true
+     # live vars: $t2
+  9: if ($t2) goto 10 else goto 12
+     # live vars:
+ 10: label L3
+     # live vars:
+ 11: goto 15
+     # live vars:
+ 12: label L4
+     # live vars:
+ 13: $t3 := 42
+     # live vars: $t3
+ 14: abort($t3)
+     # live vars:
+ 15: label L5
+     # live vars:
+ 16: $t7 := 0
+     # live vars: $t7
+ 17: $t6 := borrow_local($t7)
+     # live vars: $t6
+ 18: $t5 := read_ref($t6)
+     # live vars: $t5
+ 19: $t8 := 0
+     # live vars: $t5, $t8
+ 20: $t4 := ==($t5, $t8)
+     # live vars: $t4
+ 21: if ($t4) goto 22 else goto 24
+     # live vars:
+ 22: label L6
+     # live vars:
+ 23: goto 27
+     # live vars:
+ 24: label L7
+     # live vars:
+ 25: $t9 := 42
+     # live vars: $t9
+ 26: abort($t9)
+     # live vars:
+ 27: label L8
+     # live vars:
+ 28: $t13 := [104, 101, 108, 108, 111]
+     # live vars: $t13
+ 29: $t12 := borrow_local($t13)
+     # live vars: $t12
+ 30: $t11 := read_ref($t12)
+     # live vars: $t11
+ 31: $t14 := [104, 101, 108, 108, 111]
+     # live vars: $t11, $t14
+ 32: $t10 := ==($t11, $t14)
+     # live vars: $t10
+ 33: if ($t10) goto 34 else goto 36
+     # live vars:
+ 34: label L9
+     # live vars:
+ 35: goto 39
+     # live vars:
+ 36: label L10
+     # live vars:
+ 37: $t15 := 42
+     # live vars: $t15
+ 38: abort($t15)
+     # live vars:
+ 39: label L11
+     # live vars:
+ 40: $t17 := 0
+     # live vars: $t17
+ 41: $t16 := borrow_local($t17)
+     # live vars: $t16
+ 42: $t18 := 1
+     # live vars: $t16, $t18
+ 43: write_ref($t16, $t18)
+     # live vars: $t16
+ 44: $t20 := [104, 101, 108, 108, 111]
+     # live vars: $t16, $t20
+ 45: $t19 := borrow_local($t20)
+     # live vars: $t16, $t19
+ 46: $t21 := [98, 121, 101]
+     # live vars: $t16, $t19, $t21
+ 47: write_ref($t19, $t21)
+     # live vars: $t16, $t19
+ 48: $t23 := read_ref($t16)
+     # live vars: $t19, $t23
+ 49: $t24 := 1
+     # live vars: $t19, $t23, $t24
+ 50: $t22 := ==($t23, $t24)
+     # live vars: $t19, $t22
+ 51: if ($t22) goto 52 else goto 54
+     # live vars: $t19
+ 52: label L12
+     # live vars: $t19
+ 53: goto 57
+     # live vars: $t19
+ 54: label L13
+     # live vars:
+ 55: $t25 := 42
+     # live vars: $t25
+ 56: abort($t25)
+     # live vars: $t19
+ 57: label L14
+     # live vars: $t19
+ 58: $t27 := read_ref($t19)
+     # live vars: $t27
+ 59: $t28 := [98, 121, 101]
+     # live vars: $t27, $t28
+ 60: $t26 := ==($t27, $t28)
+     # live vars: $t26
+ 61: if ($t26) goto 62 else goto 64
+     # live vars:
+ 62: label L15
+     # live vars:
+ 63: goto 67
+     # live vars:
+ 64: label L16
+     # live vars:
+ 65: $t29 := 42
+     # live vars: $t29
+ 66: abort($t29)
+     # live vars:
+ 67: label L17
+     # live vars:
+ 68: $t30 := true
+     # live vars: $t30
+ 69: if ($t30) goto 70 else goto 72
+     # live vars:
+ 70: label L18
+     # live vars:
+ 71: goto 75
+     # live vars:
+ 72: label L19
+     # live vars:
+ 73: $t31 := 42
+     # live vars: $t31
+ 74: abort($t31)
+     # live vars:
+ 75: label L20
+     # live vars:
+ 76: $t32 := true
+     # live vars: $t32
+ 77: if ($t32) goto 78 else goto 80
+     # live vars:
+ 78: label L21
+     # live vars:
+ 79: goto 83
+     # live vars:
+ 80: label L22
+     # live vars:
+ 81: $t33 := 42
+     # live vars: $t33
+ 82: abort($t33)
+     # live vars:
+ 83: label L23
+     # live vars:
+ 84: return ()
+}
+
 ============ after ReferenceSafetyProcessor: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/copy_ability_tuple.exp b/third_party/move/move-compiler-v2/tests/ability-transform/copy_ability_tuple.exp
index 63346bfd6f41b1..739afae97ab0fd 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/copy_ability_tuple.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/copy_ability_tuple.exp
@@ -38,6 +38,40 @@ public fun M::f($t0: M::R): (M::R, u64) {
 }
 
 
+[variant baseline]
+public fun M::g($t0: &signer) {
+     var $t1: M::R
+     var $t2: u64
+     var $t3: u64
+     # live vars: $t0
+  0: $t2 := 1
+     # live vars: $t0, $t2
+  1: $t1 := pack M::R($t2)
+     # live vars: $t0, $t1
+  2: $t3 := 3
+     # live vars: $t0, $t1
+  3: ($t1, $t3) := M::f($t1)
+     # live vars: $t0, $t1
+  4: move_to<M::R>($t0, $t1)
+     # live vars:
+  5: return ()
+}
+
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+public fun M::f($t0: M::R): (M::R, u64) {
+     var $t1: M::R
+     var $t2: u64
+     # live vars: $t0
+  0: $t1 := infer($t0)
+     # live vars: $t1
+  1: $t2 := 0
+     # live vars: $t1, $t2
+  2: return ($t1, $t2)
+}
+
+
 [variant baseline]
 public fun M::g($t0: &signer) {
      var $t1: M::R
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/dead_but_borrowed.exp b/third_party/move/move-compiler-v2/tests/ability-transform/dead_but_borrowed.exp
index 66cf31cd5bc5cb..2f9cb7596ce671 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/dead_but_borrowed.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/dead_but_borrowed.exp
@@ -28,6 +28,23 @@ fun explicate_drop::test0(): u8 {
   3: return $t0
 }
 
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+fun explicate_drop::test0(): u8 {
+     var $t0: u8
+     var $t1: &u8
+     var $t2: u8
+     # live vars:
+  0: $t2 := 42
+     # live vars: $t2
+  1: $t1 := borrow_local($t2)
+     # live vars: $t1
+  2: $t0 := read_ref($t1)
+     # live vars: $t0
+  3: return $t0
+}
+
 ============ after ReferenceSafetyProcessor: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/destroy_after_call.exp b/third_party/move/move-compiler-v2/tests/ability-transform/destroy_after_call.exp
index e0c1d85b4cadef..20d836b2d2596a 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/destroy_after_call.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/destroy_after_call.exp
@@ -34,6 +34,46 @@ fun m::f($t0: &mut u64): &mut u64 {
 }
 
 
+[variant baseline]
+fun m::g() {
+     var $t0: u64
+     var $t1: &mut u64
+     var $t2: &mut u64
+     var $t3: &u64
+     # live vars:
+  0: $t0 := 22
+     # live vars: $t0
+  1: $t1 := borrow_local($t0)
+     # live vars: $t0, $t1
+  2: $t2 := m::f($t1)
+     # live vars: $t0, $t2
+  3: $t1 := infer($t2)
+     # live vars: $t0
+  4: $t3 := borrow_local($t0)
+     # live vars:
+  5: return ()
+}
+
+
+Diagnostics:
+warning: Unused assignment to r. Consider removing or prefixing with an underscore: `_r`
+  ┌─ tests/ability-transform/destroy_after_call.move:8:9
+  │
+8 │         r = f(r);
+  │         ^^^^^^^^
+
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+fun m::f($t0: &mut u64): &mut u64 {
+     var $t1: &mut u64
+     # live vars: $t0
+  0: $t1 := infer($t0)
+     # live vars: $t1
+  1: return $t1
+}
+
+
 [variant baseline]
 fun m::g() {
      var $t0: u64
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/drop_after_loop.exp b/third_party/move/move-compiler-v2/tests/ability-transform/drop_after_loop.exp
index 257b1bae0d6cd1..77edac67936f6b 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/drop_after_loop.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/drop_after_loop.exp
@@ -104,6 +104,72 @@ fun m::drop_after_loop() {
  25: return ()
 }
 
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+fun m::drop_after_loop() {
+     var $t0: u64
+     var $t1: &mut u64
+     var $t2: bool
+     var $t3: u64
+     var $t4: bool
+     var $t5: bool
+     var $t6: u64
+     var $t7: u64
+     # live vars:
+  0: $t0 := 1
+     # live vars: $t0
+  1: $t1 := borrow_local($t0)
+     # live vars: $t0, $t1
+  2: $t2 := true
+     # live vars: $t0, $t1, $t2
+  3: label L0
+     # live vars: $t0, $t1, $t2
+  4: if ($t2) goto 5 else goto 11
+     # live vars: $t0, $t1
+  5: label L2
+     # live vars: $t0, $t1
+  6: $t3 := 2
+     # live vars: $t0, $t1, $t3
+  7: write_ref($t1, $t3)
+     # live vars: $t0, $t1
+  8: $t4 := false
+     # live vars: $t0, $t1, $t4
+  9: $t2 := infer($t4)
+     # live vars: $t0, $t1, $t2
+ 10: goto 13
+     # live vars: $t0, $t1
+ 11: label L3
+     # live vars: $t0
+ 12: goto 15
+     # live vars: $t0, $t1, $t2
+ 13: label L4
+     # live vars: $t0, $t1, $t2
+ 14: goto 3
+     # live vars: $t0
+ 15: label L1
+     # live vars: $t0
+ 16: $t6 := 2
+     # live vars: $t0, $t6
+ 17: $t5 := ==($t0, $t6)
+     # live vars: $t5
+ 18: if ($t5) goto 19 else goto 21
+     # live vars:
+ 19: label L5
+     # live vars:
+ 20: goto 24
+     # live vars:
+ 21: label L6
+     # live vars:
+ 22: $t7 := 0
+     # live vars: $t7
+ 23: abort($t7)
+     # live vars:
+ 24: label L7
+     # live vars:
+ 25: return ()
+}
+
 ============ after ReferenceSafetyProcessor: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/drop_at_branch.exp b/third_party/move/move-compiler-v2/tests/ability-transform/drop_at_branch.exp
index 7b5153dffd6dd0..baaa593bf4a384 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/drop_at_branch.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/drop_at_branch.exp
@@ -36,6 +36,29 @@ fun explicate_drop::drop_at_branch($t0: bool): u8 {
   7: return $t1
 }
 
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+fun explicate_drop::drop_at_branch($t0: bool): u8 {
+     var $t1: u8
+     # live vars: $t0
+  0: if ($t0) goto 1 else goto 4
+     # live vars:
+  1: label L0
+     # live vars:
+  2: $t1 := 1
+     # live vars: $t1
+  3: goto 6
+     # live vars:
+  4: label L1
+     # live vars:
+  5: $t1 := 0
+     # live vars: $t1
+  6: label L2
+     # live vars: $t1
+  7: return $t1
+}
+
 ============ after ReferenceSafetyProcessor: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/foreach_mut_expanded.exp b/third_party/move/move-compiler-v2/tests/ability-transform/foreach_mut_expanded.exp
index f696ee52a0ffbf..57cddffaf1f901 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/foreach_mut_expanded.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/foreach_mut_expanded.exp
@@ -129,6 +129,87 @@ fun m::test_for_each_mut() {
  30: return ()
 }
 
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+fun m::test_for_each_mut() {
+     var $t0: vector<u64>
+     var $t1: u64
+     var $t2: u64
+     var $t3: &vector<u64>
+     var $t4: &mut vector<u64>
+     var $t5: bool
+     var $t6: &mut u64
+     var $t7: u64
+     var $t8: u64
+     var $t9: u64
+     var $t10: bool
+     var $t11: vector<u64>
+     var $t12: u64
+     # live vars:
+  0: $t0 := ["1", "2", "3"]
+     # live vars: $t0
+  1: $t1 := 0
+     # live vars: $t0, $t1
+  2: $t3 := borrow_local($t0)
+     # live vars: $t0, $t1, $t3
+  3: $t2 := vector::length<u64>($t3)
+     # live vars: $t0, $t1, $t2
+  4: $t4 := borrow_local($t0)
+     # live vars: $t0, $t1, $t2, $t4
+  5: label L0
+     # live vars: $t0, $t1, $t2, $t4
+  6: $t5 := <($t1, $t2)
+     # live vars: $t0, $t1, $t2, $t4, $t5
+  7: if ($t5) goto 8 else goto 16
+     # live vars: $t0, $t1, $t2, $t4
+  8: label L2
+     # live vars: $t0, $t1, $t2, $t4
+  9: $t6 := vector::borrow_mut<u64>($t4, $t1)
+     # live vars: $t0, $t1, $t2, $t4, $t6
+ 10: $t7 := 2
+     # live vars: $t0, $t1, $t2, $t4, $t6, $t7
+ 11: write_ref($t6, $t7)
+     # live vars: $t0, $t1, $t2, $t4
+ 12: $t9 := 1
+     # live vars: $t0, $t1, $t2, $t4, $t9
+ 13: $t8 := +($t1, $t9)
+     # live vars: $t0, $t2, $t4, $t8
+ 14: $t1 := infer($t8)
+     # live vars: $t0, $t1, $t2, $t4
+ 15: goto 18
+     # live vars: $t0, $t1, $t2, $t4
+ 16: label L3
+     # live vars: $t0
+ 17: goto 20
+     # live vars: $t0, $t1, $t2, $t4
+ 18: label L4
+     # live vars: $t0, $t1, $t2, $t4
+ 19: goto 5
+     # live vars: $t0
+ 20: label L1
+     # live vars: $t0
+ 21: $t11 := ["2", "3", "4"]
+     # live vars: $t0, $t11
+ 22: $t10 := ==($t0, $t11)
+     # live vars: $t10
+ 23: if ($t10) goto 24 else goto 26
+     # live vars:
+ 24: label L5
+     # live vars:
+ 25: goto 29
+     # live vars:
+ 26: label L6
+     # live vars:
+ 27: $t12 := 0
+     # live vars: $t12
+ 28: abort($t12)
+     # live vars:
+ 29: label L7
+     # live vars:
+ 30: return ()
+}
+
 ============ after ReferenceSafetyProcessor: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/mutate_return.exp b/third_party/move/move-compiler-v2/tests/ability-transform/mutate_return.exp
index e83571eda35db5..f7f2e990167a20 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/mutate_return.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/mutate_return.exp
@@ -38,6 +38,32 @@ public fun m::singleton<#0>($t0: #0): vector<#0> {
 }
 
 
+[variant baseline]
+fun m::g<#0>($t0: &mut vector<#0>) {
+     # live vars: $t0
+  0: return ()
+}
+
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+public fun m::singleton<#0>($t0: #0): vector<#0> {
+     var $t1: vector<#0>
+     var $t2: vector<#0>
+     var $t3: &mut vector<#0>
+     # live vars: $t0
+  0: $t2 := vector($t0)
+     # live vars: $t2
+  1: $t3 := borrow_local($t2)
+     # live vars: $t2, $t3
+  2: m::g<#0>($t3)
+     # live vars: $t2
+  3: $t1 := infer($t2)
+     # live vars: $t1
+  4: return $t1
+}
+
+
 [variant baseline]
 fun m::g<#0>($t0: &mut vector<#0>) {
      # live vars: $t0
diff --git a/third_party/move/move-compiler-v2/tests/ability-transform/mutate_vector.exp b/third_party/move/move-compiler-v2/tests/ability-transform/mutate_vector.exp
index dcfea63e6ee362..c9b8e8c2e45745 100644
--- a/third_party/move/move-compiler-v2/tests/ability-transform/mutate_vector.exp
+++ b/third_party/move/move-compiler-v2/tests/ability-transform/mutate_vector.exp
@@ -57,6 +57,47 @@ public fun m::new_scalar_from_u8($t0: u8): m::Scalar {
 }
 
 
+[variant baseline]
+public fun m::scalar_zero(): m::Scalar {
+     var $t0: m::Scalar
+     var $t1: vector<u8>
+     # live vars:
+  0: $t1 := [0]
+     # live vars: $t1
+  1: $t0 := pack m::Scalar($t1)
+     # live vars: $t0
+  2: return $t0
+}
+
+============ after LiveVarAnalysisProcessor: ================
+
+[variant baseline]
+public fun m::new_scalar_from_u8($t0: u8): m::Scalar {
+     var $t1: m::Scalar
+     var $t2: m::Scalar
+     var $t3: &mut u8
+     var $t4: &mut vector<u8>
+     var $t5: &mut m::Scalar
+     var $t6: u64
+     # live vars: $t0
+  0: $t2 := m::scalar_zero()
+     # live vars: $t0, $t2
+  1: $t5 := borrow_local($t2)
+     # live vars: $t0, $t2, $t5
+  2: $t4 := borrow_field<m::Scalar>.data($t5)
+     # live vars: $t0, $t2, $t4
+  3: $t6 := 0
+     # live vars: $t0, $t2, $t4, $t6
+  4: $t3 := vector::borrow_mut<u8>($t4, $t6)
+     # live vars: $t0, $t2, $t3
+  5: write_ref($t3, $t0)
+     # live vars: $t2
+  6: $t1 := infer($t2)
+     # live vars: $t1
+  7: return $t1
+}
+
+
 [variant baseline]
 public fun m::scalar_zero(): m::Scalar {
      var $t0: m::Scalar
diff --git a/third_party/move/move-compiler-v2/tests/bytecode-generator/freeze_mut_ref.exp b/third_party/move/move-compiler-v2/tests/bytecode-generator/freeze_mut_ref.exp
index ab3905586b4a9f..cfb3f2f89629fa 100644
--- a/third_party/move/move-compiler-v2/tests/bytecode-generator/freeze_mut_ref.exp
+++ b/third_party/move/move-compiler-v2/tests/bytecode-generator/freeze_mut_ref.exp
@@ -294,6 +294,44 @@ fun freeze_mut_ref::t8($t0: bool, $t1: &mut freeze_mut_ref::S, $t2: &freeze_mut_
 }
 
 
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+   ┌─ tests/bytecode-generator/freeze_mut_ref.move:58:9
+   │
+58 │         (x, y) = (&mut 0, &mut 0);
+   │         ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+   ┌─ tests/bytecode-generator/freeze_mut_ref.move:58:9
+   │
+58 │         (x, y) = (&mut 0, &mut 0);
+   │         ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+   ┌─ tests/bytecode-generator/freeze_mut_ref.move:66:24
+   │
+66 │         let g = &mut ({x = x + 1; s}).f;
+   │                        ^^^^^^^^^
+
+warning: Unused assignment to z. Consider removing or prefixing with an underscore: `_z`
+   ┌─ tests/bytecode-generator/freeze_mut_ref.move:69:20
+   │
+69 │         *({*f = 0; z = y; g}) = 2;
+   │                    ^^^^^
+
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+   ┌─ tests/bytecode-generator/freeze_mut_ref.move:74:19
+   │
+74 │         if (cond) x = copy s else x = other;
+   │                   ^^^^^^^^^^
+
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+   ┌─ tests/bytecode-generator/freeze_mut_ref.move:74:35
+   │
+74 │         if (cond) x = copy s else x = other;
+   │                                   ^^^^^^^^^
+
+
 Diagnostics:
 error: mutable reference in local `s` requires exclusive access but is borrowed
    ┌─ tests/bytecode-generator/freeze_mut_ref.move:66:35
diff --git a/third_party/move/move-compiler-v2/tests/bytecode-generator/wildcard7.exp b/third_party/move/move-compiler-v2/tests/bytecode-generator/wildcard7.exp
index 1e6874b74166b3..52ecc2e51d1041 100644
--- a/third_party/move/move-compiler-v2/tests/bytecode-generator/wildcard7.exp
+++ b/third_party/move/move-compiler-v2/tests/bytecode-generator/wildcard7.exp
@@ -42,6 +42,14 @@ public fun m::test(): u8 {
 }
 
 
+Diagnostics:
+warning: Unused assignment to q. Consider removing or prefixing with an underscore: `_q`
+  ┌─ tests/bytecode-generator/wildcard7.move:6:13
+  │
+6 │         let (_, q) = (x, z);
+  │             ^^^^^^
+
+
 Diagnostics:
 error: cannot move local `x` since it is still in use
   ┌─ tests/bytecode-generator/wildcard7.move:5:17
diff --git a/third_party/move/move-compiler-v2/tests/copy-propagation/call_1.exp b/third_party/move/move-compiler-v2/tests/copy-propagation/call_1.exp
index 1d261d0a9ea43e..94b096bdb1f9ce 100644
--- a/third_party/move/move-compiler-v2/tests/copy-propagation/call_1.exp
+++ b/third_party/move/move-compiler-v2/tests/copy-propagation/call_1.exp
@@ -33,6 +33,14 @@ fun m::test($t0: u64): u64 {
   6: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/copy-propagation/call_1.move:7:17
+  │
+7 │         let a = p;
+  │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/copy-propagation/seq_kills_1.exp b/third_party/move/move-compiler-v2/tests/copy-propagation/seq_kills_1.exp
index 55bc0e2c25d3d0..0a8c2152af74dc 100644
--- a/third_party/move/move-compiler-v2/tests/copy-propagation/seq_kills_1.exp
+++ b/third_party/move/move-compiler-v2/tests/copy-propagation/seq_kills_1.exp
@@ -18,6 +18,14 @@ fun m::test($t0: u64): bool {
   7: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to b. Consider removing or prefixing with an underscore: `_b`
+  ┌─ tests/copy-propagation/seq_kills_1.move:7:9
+  │
+7 │         b = p + 1; // kill b := a, which removes the whole copy chain
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/copy-propagation/seq_kills_2.exp b/third_party/move/move-compiler-v2/tests/copy-propagation/seq_kills_2.exp
index 3680de01d0e30d..e7fe96349524a2 100644
--- a/third_party/move/move-compiler-v2/tests/copy-propagation/seq_kills_2.exp
+++ b/third_party/move/move-compiler-v2/tests/copy-propagation/seq_kills_2.exp
@@ -18,6 +18,14 @@ fun m::test($t0: u64): bool {
   7: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/copy-propagation/seq_kills_2.move:7:9
+  │
+7 │         a = p + 1; // kill b := a
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/copy-propagation/straight_line_kills.exp b/third_party/move/move-compiler-v2/tests/copy-propagation/straight_line_kills.exp
index aeb8910c1d774f..06c4d6fa894541 100644
--- a/third_party/move/move-compiler-v2/tests/copy-propagation/straight_line_kills.exp
+++ b/third_party/move/move-compiler-v2/tests/copy-propagation/straight_line_kills.exp
@@ -16,6 +16,14 @@ fun m::copy_kill($t0: u64): u64 {
   6: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to p. Consider removing or prefixing with an underscore: `_p`
+  ┌─ tests/copy-propagation/straight_line_kills.move:5:9
+  │
+5 │         p = p + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/reference-safety/write_ref_dest.exp b/third_party/move/move-compiler-v2/tests/reference-safety/write_ref_dest.exp
index 90b32906711cc7..fe1cfaa36d8e69 100644
--- a/third_party/move/move-compiler-v2/tests/reference-safety/write_ref_dest.exp
+++ b/third_party/move/move-compiler-v2/tests/reference-safety/write_ref_dest.exp
@@ -1,2 +1,10 @@
 
+Diagnostics:
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+   ┌─ tests/reference-safety/write_ref_dest.move:16:9
+   │
+16 │         (y, _) = (*&y, 1);
+   │         ^^^^^^^^^^^^^^^^^
+
+
 ============ bytecode verification succeeded ========
diff --git a/third_party/move/move-compiler-v2/tests/reference-safety/write_ref_dest.no-opt.exp b/third_party/move/move-compiler-v2/tests/reference-safety/write_ref_dest.no-opt.exp
index 90b32906711cc7..fe1cfaa36d8e69 100644
--- a/third_party/move/move-compiler-v2/tests/reference-safety/write_ref_dest.no-opt.exp
+++ b/third_party/move/move-compiler-v2/tests/reference-safety/write_ref_dest.no-opt.exp
@@ -1,2 +1,10 @@
 
+Diagnostics:
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+   ┌─ tests/reference-safety/write_ref_dest.move:16:9
+   │
+16 │         (y, _) = (*&y, 1);
+   │         ^^^^^^^^^^^^^^^^^
+
+
 ============ bytecode verification succeeded ========
diff --git a/third_party/move/move-compiler-v2/tests/simplifier-elimination/bind_with_type_annot.exp b/third_party/move/move-compiler-v2/tests/simplifier-elimination/bind_with_type_annot.exp
index bd47ab1047bbe1..3aae1dd3118547 100644
--- a/third_party/move/move-compiler-v2/tests/simplifier-elimination/bind_with_type_annot.exp
+++ b/third_party/move/move-compiler-v2/tests/simplifier-elimination/bind_with_type_annot.exp
@@ -38,4 +38,18 @@ module 0x8675309::M {
 } // end 0x8675309::M
 
 
+Diagnostics:
+warning: Unused assignment to b. Consider removing or prefixing with an underscore: `_b`
+  ┌─ tests/simplifier-elimination/bind_with_type_annot.move:7:13
+  │
+7 │         let (x, b, R{f}): (u64, bool, R) = (0, false, R { f: 0 }); x; b; f;
+  │             ^^^^^^^^^^^^
+
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/simplifier-elimination/bind_with_type_annot.move:7:13
+  │
+7 │         let (x, b, R{f}): (u64, bool, R) = (0, false, R { f: 0 }); x; b; f;
+  │             ^^^^^^^^^^^^
+
+
 ============ bytecode verification succeeded ========
diff --git a/third_party/move/move-compiler-v2/tests/simplifier-elimination/use_before_assign.exp b/third_party/move/move-compiler-v2/tests/simplifier-elimination/use_before_assign.exp
index ac63e9d86f699f..b9a8559d1141cd 100644
--- a/third_party/move/move-compiler-v2/tests/simplifier-elimination/use_before_assign.exp
+++ b/third_party/move/move-compiler-v2/tests/simplifier-elimination/use_before_assign.exp
@@ -26,3 +26,11 @@ error: use of unassigned local `x`
   │
 4 │     let y = x;
   │             ^
+
+
+Diagnostics:
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+  ┌─ tests/simplifier-elimination/use_before_assign.move:4:13
+  │
+4 │     let y = x;
+  │             ^
diff --git a/third_party/move/move-compiler-v2/tests/simplifier-elimination/use_before_assign_while.exp b/third_party/move/move-compiler-v2/tests/simplifier-elimination/use_before_assign_while.exp
index 223526a98870c4..257f8e5a68f598 100644
--- a/third_party/move/move-compiler-v2/tests/simplifier-elimination/use_before_assign_while.exp
+++ b/third_party/move/move-compiler-v2/tests/simplifier-elimination/use_before_assign_while.exp
@@ -105,6 +105,14 @@ error: use of unassigned local `x`
    │                                ^^
 
 
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+   ┌─ tests/simplifier-elimination/use_before_assign_while.move:19:60
+   │
+19 │         while (cond) { let y = &x; _ = move y; if (cond) { x = 0 }; break }
+   │                                                            ^^^^^
+
+
 Diagnostics:
 error: cannot move local `x` since it is still in use
   ┌─ tests/simplifier-elimination/use_before_assign_while.move:9:32
diff --git a/third_party/move/move-compiler-v2/tests/simplifier/random.exp b/third_party/move/move-compiler-v2/tests/simplifier/random.exp
index c476659b15e236..3fb15975714b42 100644
--- a/third_party/move/move-compiler-v2/tests/simplifier/random.exp
+++ b/third_party/move/move-compiler-v2/tests/simplifier/random.exp
@@ -144,6 +144,14 @@ module 0x8675::M {
 } // end 0x8675::M
 
 
+Diagnostics:
+warning: Unused assignment to q. Consider removing or prefixing with an underscore: `_q`
+   ┌─ tests/simplifier/random.move:48:17
+   │
+48 │         let q = v;
+   │                 ^
+
+
 Diagnostics:
 error: cannot mutably borrow since immutable references exist
    ┌─ tests/simplifier/random.move:56:17
diff --git a/third_party/move/move-compiler-v2/tests/unreachable-code-remover/conditional_loop_unreachable.exp b/third_party/move/move-compiler-v2/tests/unreachable-code-remover/conditional_loop_unreachable.exp
index 189a01e97ca647..90f944ba87f6fd 100644
--- a/third_party/move/move-compiler-v2/tests/unreachable-code-remover/conditional_loop_unreachable.exp
+++ b/third_party/move/move-compiler-v2/tests/unreachable-code-remover/conditional_loop_unreachable.exp
@@ -37,6 +37,20 @@ fun m::test($t0: bool, $t1: bool) {
  26: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to i. Consider removing or prefixing with an underscore: `_i`
+  ┌─ tests/unreachable-code-remover/conditional_loop_unreachable.move:7:17
+  │
+7 │                 i = i + 1;
+  │                 ^^^^^^^^^
+
+warning: Unused assignment to i. Consider removing or prefixing with an underscore: `_i`
+   ┌─ tests/unreachable-code-remover/conditional_loop_unreachable.move:12:13
+   │
+12 │             i = i + 1;
+   │             ^^^^^^^^^
+
 ============ after UnreachableCodeProcessor: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/call_1.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/call_1.exp
index 8cb6654d0e5633..8c6a6af8b1aaa5 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/call_1.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/call_1.exp
@@ -33,6 +33,14 @@ fun m::test($t0: u64): u64 {
   6: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/variable-coalescing/call_1.move:7:17
+  │
+7 │         let a = p;
+  │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/call_1.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/call_1.opt.exp
index 8cb6654d0e5633..8c6a6af8b1aaa5 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/call_1.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/call_1.opt.exp
@@ -33,6 +33,14 @@ fun m::test($t0: u64): u64 {
   6: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/variable-coalescing/call_1.move:7:17
+  │
+7 │         let a = p;
+  │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/cant_copy_propagate.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/cant_copy_propagate.exp
index 714466fd830f4b..4b0d42e60dde33 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/cant_copy_propagate.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/cant_copy_propagate.exp
@@ -31,6 +31,20 @@ fun m::test($t0: u64, $t1: bool) {
  13: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+   ┌─ tests/variable-coalescing/cant_copy_propagate.move:11:13
+   │
+11 │             a = 99;
+   │             ^^^^^^
+
+warning: Unused assignment to c. Consider removing or prefixing with an underscore: `_c`
+   ┌─ tests/variable-coalescing/cant_copy_propagate.move:13:13
+   │
+13 │             c = c + 1;
+   │             ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/cant_copy_propagate.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/cant_copy_propagate.opt.exp
index 714466fd830f4b..4b0d42e60dde33 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/cant_copy_propagate.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/cant_copy_propagate.opt.exp
@@ -31,6 +31,20 @@ fun m::test($t0: u64, $t1: bool) {
  13: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+   ┌─ tests/variable-coalescing/cant_copy_propagate.move:11:13
+   │
+11 │             a = 99;
+   │             ^^^^^^
+
+warning: Unused assignment to c. Consider removing or prefixing with an underscore: `_c`
+   ┌─ tests/variable-coalescing/cant_copy_propagate.move:13:13
+   │
+13 │             c = c + 1;
+   │             ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/cyclic_assignment_without_use.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/cyclic_assignment_without_use.exp
index 1be5d8b6fc8ed1..61cab7e1a35942 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/cyclic_assignment_without_use.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/cyclic_assignment_without_use.exp
@@ -12,6 +12,14 @@ public fun m::test($t0: u64) {
   4: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/variable-coalescing/cyclic_assignment_without_use.move:6:9
+  │
+6 │         a = c;
+  │         ^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/cyclic_assignment_without_use.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/cyclic_assignment_without_use.opt.exp
index 1be5d8b6fc8ed1..61cab7e1a35942 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/cyclic_assignment_without_use.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/cyclic_assignment_without_use.opt.exp
@@ -12,6 +12,14 @@ public fun m::test($t0: u64) {
   4: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/variable-coalescing/cyclic_assignment_without_use.move:6:9
+  │
+6 │         a = c;
+  │         ^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_3.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_3.exp
index 2ab2fd8b365f92..a7a488752275b5 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_3.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_3.exp
@@ -20,6 +20,14 @@ public fun m::test($t0: bool): u32 {
  12: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+   ┌─ tests/variable-coalescing/dead_assignment_3.move:10:13
+   │
+10 │             y = y;
+   │             ^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_3.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_3.opt.exp
index 10501d30e99430..78fe916a30c793 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_3.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_3.opt.exp
@@ -18,6 +18,14 @@ public fun m::test($t0: bool): u32 {
  11: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+   ┌─ tests/variable-coalescing/dead_assignment_3.move:10:13
+   │
+10 │             y = y;
+   │             ^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_4.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_4.exp
index 4dac3143233377..412603b8179550 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_4.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_4.exp
@@ -67,6 +67,26 @@ public fun m::test4($t0: u64): u64 {
   2: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/dead_assignment_4.move:3:17
+  │
+3 │         let x = 1;
+  │                 ^
+
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/dead_assignment_4.move:9:17
+  │
+9 │         let x = y;
+  │                 ^
+
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+   ┌─ tests/variable-coalescing/dead_assignment_4.move:14:17
+   │
+14 │         let x = y;
+   │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_4.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_4.opt.exp
index 6a523fee558e21..0222b7b9f8e9db 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_4.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/dead_assignment_4.opt.exp
@@ -61,6 +61,20 @@ public fun m::test4($t0: u64): u64 {
   1: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/dead_assignment_4.move:9:17
+  │
+9 │         let x = y;
+  │                 ^
+
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+   ┌─ tests/variable-coalescing/dead_assignment_4.move:14:17
+   │
+14 │         let x = y;
+   │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_1.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_1.exp
index 8ad92bf6813751..c6306637c13e6f 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_1.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_1.exp
@@ -16,6 +16,14 @@ fun m::test(): u64 {
   6: return $t0
 }
 
+
+Diagnostics:
+warning: Unused assignment to t. Consider removing or prefixing with an underscore: `_t`
+  ┌─ tests/variable-coalescing/intermingled_1.move:5:9
+  │
+5 │         t = t + u;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_1.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_1.opt.exp
index c8d8e9c9ea66be..0da5fe2264ad2b 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_1.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_1.opt.exp
@@ -14,6 +14,14 @@ fun m::test(): u64 {
   5: return $t0
 }
 
+
+Diagnostics:
+warning: Unused assignment to t. Consider removing or prefixing with an underscore: `_t`
+  ┌─ tests/variable-coalescing/intermingled_1.move:5:9
+  │
+5 │         t = t + u;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_3.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_3.exp
index 5d50b3f39fdac3..777aaaf3b6c421 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_3.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_3.exp
@@ -18,6 +18,14 @@ fun m::test(): u64 {
   7: return $t0
 }
 
+
+Diagnostics:
+warning: Unused assignment to t. Consider removing or prefixing with an underscore: `_t`
+  ┌─ tests/variable-coalescing/intermingled_3.move:5:9
+  │
+5 │         t = t + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_3.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_3.opt.exp
index dd35312daf6a4e..422b8bb6b5b2ea 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_3.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/intermingled_3.opt.exp
@@ -14,6 +14,14 @@ fun m::test(): u64 {
   5: return $t0
 }
 
+
+Diagnostics:
+warning: Unused assignment to t. Consider removing or prefixing with an underscore: `_t`
+  ┌─ tests/variable-coalescing/intermingled_3.move:5:9
+  │
+5 │         t = t + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/multi_assigns.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/multi_assigns.exp
index 487f77be960ef3..c1cc7a4b6ac492 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/multi_assigns.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/multi_assigns.exp
@@ -12,6 +12,14 @@ fun m::test(): u64 {
   4: return $t0
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/multi_assigns.move:3:17
+  │
+3 │         let x = 1;
+  │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/multi_assigns.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/multi_assigns.opt.exp
index 487f77be960ef3..c1cc7a4b6ac492 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/multi_assigns.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/multi_assigns.opt.exp
@@ -12,6 +12,14 @@ fun m::test(): u64 {
   4: return $t0
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/multi_assigns.move:3:17
+  │
+3 │         let x = 1;
+  │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars1.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars1.exp
index 754941c7088808..d43250bd173d11 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars1.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars1.exp
@@ -19,6 +19,20 @@ fun m::test() {
   8: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/non_overlapping_vars1.move:4:9
+  │
+4 │         x = x + 1;
+  │         ^^^^^^^^^
+
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+  ┌─ tests/variable-coalescing/non_overlapping_vars1.move:6:9
+  │
+6 │         y = y + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars1.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars1.opt.exp
index 754941c7088808..d43250bd173d11 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars1.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars1.opt.exp
@@ -19,6 +19,20 @@ fun m::test() {
   8: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/non_overlapping_vars1.move:4:9
+  │
+4 │         x = x + 1;
+  │         ^^^^^^^^^
+
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+  ┌─ tests/variable-coalescing/non_overlapping_vars1.move:6:9
+  │
+6 │         y = y + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars_diff_type.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars_diff_type.exp
index b7f839ff0a1948..9f824872b31b9a 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars_diff_type.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars_diff_type.exp
@@ -19,6 +19,20 @@ fun m::test() {
   8: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/non_overlapping_vars_diff_type.move:4:9
+  │
+4 │         x = x + 1;
+  │         ^^^^^^^^^
+
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+  ┌─ tests/variable-coalescing/non_overlapping_vars_diff_type.move:6:9
+  │
+6 │         y = y + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars_diff_type.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars_diff_type.opt.exp
index b7f839ff0a1948..9f824872b31b9a 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars_diff_type.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/non_overlapping_vars_diff_type.opt.exp
@@ -19,6 +19,20 @@ fun m::test() {
   8: return ()
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/non_overlapping_vars_diff_type.move:4:9
+  │
+4 │         x = x + 1;
+  │         ^^^^^^^^^
+
+warning: Unused assignment to y. Consider removing or prefixing with an underscore: `_y`
+  ┌─ tests/variable-coalescing/non_overlapping_vars_diff_type.move:6:9
+  │
+6 │         y = y + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/reassigned_var.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/reassigned_var.exp
index 5a165b49ca4cad..9d63663210e102 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/reassigned_var.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/reassigned_var.exp
@@ -14,6 +14,14 @@ fun m::test(): u64 {
   5: return $t0
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/variable-coalescing/reassigned_var.move:3:17
+  │
+3 │         let a = 1;
+  │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/reassigned_var.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/reassigned_var.opt.exp
index 23428eb311af1e..14b6c39de5a2b2 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/reassigned_var.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/reassigned_var.opt.exp
@@ -14,6 +14,14 @@ fun m::test(): u64 {
   5: return $t0
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/variable-coalescing/reassigned_var.move:3:17
+  │
+3 │         let a = 1;
+  │                 ^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/self_assigns.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/self_assigns.exp
index 22650ed85bc01e..caa8ce9392fd3b 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/self_assigns.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/self_assigns.exp
@@ -75,6 +75,14 @@ public fun m::test4($t0: u64): u64 {
  17: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/self_assigns.move:3:9
+  │
+3 │         x = x;
+  │         ^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/self_assigns.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/self_assigns.opt.exp
index 22650ed85bc01e..caa8ce9392fd3b 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/self_assigns.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/self_assigns.opt.exp
@@ -75,6 +75,14 @@ public fun m::test4($t0: u64): u64 {
  17: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to x. Consider removing or prefixing with an underscore: `_x`
+  ┌─ tests/variable-coalescing/self_assigns.move:3:9
+  │
+3 │         x = x;
+  │         ^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_1.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_1.exp
index dc7553994cc1a4..90272cacfb7791 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_1.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_1.exp
@@ -18,6 +18,14 @@ fun m::test($t0: u64): bool {
   7: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to b. Consider removing or prefixing with an underscore: `_b`
+  ┌─ tests/variable-coalescing/seq_kills_1.move:7:9
+  │
+7 │         b = p + 1; // kill b := a, which removes the whole copy chain
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_1.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_1.opt.exp
index dc7553994cc1a4..90272cacfb7791 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_1.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_1.opt.exp
@@ -18,6 +18,14 @@ fun m::test($t0: u64): bool {
   7: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to b. Consider removing or prefixing with an underscore: `_b`
+  ┌─ tests/variable-coalescing/seq_kills_1.move:7:9
+  │
+7 │         b = p + 1; // kill b := a, which removes the whole copy chain
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_2.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_2.exp
index 3cbb873f10bd00..074d2b0da68bca 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_2.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_2.exp
@@ -18,6 +18,14 @@ fun m::test($t0: u64): bool {
   7: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/variable-coalescing/seq_kills_2.move:7:9
+  │
+7 │         a = p + 1; // kill b := a
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_2.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_2.opt.exp
index 3cbb873f10bd00..074d2b0da68bca 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_2.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/seq_kills_2.opt.exp
@@ -18,6 +18,14 @@ fun m::test($t0: u64): bool {
   7: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to a. Consider removing or prefixing with an underscore: `_a`
+  ┌─ tests/variable-coalescing/seq_kills_2.move:7:9
+  │
+7 │         a = p + 1; // kill b := a
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/straight_line_kills.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/straight_line_kills.exp
index 244a78cdaba552..1cba528fd9f38f 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/straight_line_kills.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/straight_line_kills.exp
@@ -16,6 +16,14 @@ fun m::copy_kill($t0: u64): u64 {
   6: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to p. Consider removing or prefixing with an underscore: `_p`
+  ┌─ tests/variable-coalescing/straight_line_kills.move:5:9
+  │
+5 │         p = p + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]
diff --git a/third_party/move/move-compiler-v2/tests/variable-coalescing/straight_line_kills.opt.exp b/third_party/move/move-compiler-v2/tests/variable-coalescing/straight_line_kills.opt.exp
index 244a78cdaba552..1cba528fd9f38f 100644
--- a/third_party/move/move-compiler-v2/tests/variable-coalescing/straight_line_kills.opt.exp
+++ b/third_party/move/move-compiler-v2/tests/variable-coalescing/straight_line_kills.opt.exp
@@ -16,6 +16,14 @@ fun m::copy_kill($t0: u64): u64 {
   6: return $t1
 }
 
+
+Diagnostics:
+warning: Unused assignment to p. Consider removing or prefixing with an underscore: `_p`
+  ┌─ tests/variable-coalescing/straight_line_kills.move:5:9
+  │
+5 │         p = p + 1;
+  │         ^^^^^^^^^
+
 ============ after DeadStoreElimination: ================
 
 [variant baseline]