diff --git a/compiler/forget/src/HIR/InferMutableLifetimes.ts b/compiler/forget/src/HIR/InferMutableLifetimes.ts
index abe2d2aa5e..37ad4f500e 100644
--- a/compiler/forget/src/HIR/InferMutableLifetimes.ts
+++ b/compiler/forget/src/HIR/InferMutableLifetimes.ts
@@ -132,7 +132,7 @@ export function inferMutableRanges(func: HIRFunction) {
     // Update mutableRange.end only if the identifiers have actually been
     // mutated.
     const haveIdentifiersBeenMutated = [...aliasSet].some(
-      (id) => id.mutableRange.end > id.mutableRange.start
+      (id) => id.mutableRange.end - id.mutableRange.start > 1
     );
 
     if (haveIdentifiersBeenMutated) {
diff --git a/compiler/forget/src/__tests__/fixtures/hir/frozen-after-alias.expect.md b/compiler/forget/src/__tests__/fixtures/hir/frozen-after-alias.expect.md
index 5b849e150b..94852ad18c 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/frozen-after-alias.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/frozen-after-alias.expect.md
@@ -18,12 +18,14 @@ function foo(x) {}
 
 ```
 bb0:
-  [1] Const mutate a$5_@0[1:3] = Array []
-  [2] Const mutate b$6_@0[1:3] = read a$5_@0
+  [1] Const mutate a$5_@0 = Array []
+  [2] Const mutate b$6_@1 = read a$5_@0
   [3] Call read useFreeze$3(freeze a$5_@0)
-  [4] Call mutate foo$4_@1(read b$6_@0)
+  [4] Call mutate foo$4_@2(read b$6_@1)
   [5] Return
-
+scope1 [2:3]:
+ - read a$5_@0
+ - freeze a$5_@0
 ```
 
 ### CFG
@@ -33,10 +35,10 @@ flowchart TB
   %% Basic Blocks
   subgraph bb0
     bb0_instrs["
-      [1] Const mutate a$5_@0[1:3] = Array []
-      [2] Const mutate b$6_@0[1:3] = read a$5_@0
+      [1] Const mutate a$5_@0 = Array []
+      [2] Const mutate b$6_@1 = read a$5_@0
       [3] Call read useFreeze$3(freeze a$5_@0)
-      [4] Call mutate foo$4_@1(read b$6_@0)
+      [4] Call mutate foo$4_@2(read b$6_@1)
     "]
     bb0_instrs --> bb0_terminal(["Return"])
   end
diff --git a/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-possibly-mutable-arguments.expect.md b/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-possibly-mutable-arguments.expect.md
index 3f7be568aa..4b570c3214 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-possibly-mutable-arguments.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-possibly-mutable-arguments.expect.md
@@ -27,29 +27,30 @@ function call(x) {}
 ```
 bb0:
   [1] Const mutate cond$8_@0 = read props$7.cond
-  [2] Const mutate x$9_@1[2:9] = read props$7.x
+  [2] Const mutate x$9_@1 = read props$7.x
   [3] Let mutate a$10_@2 = undefined
   [4] If (read cond$8_@0) then:bb2 else:bb3
 bb2:
   predecessor blocks: bb0
-  [5] Reassign mutate a$11_@1[2:9] = read x$9_@1
+  [5] Reassign mutate a$11_@3[5:8] = read x$9_@1
   [6] Goto bb1
 bb3:
   predecessor blocks: bb0
-  [7] Reassign mutate a$12_@1[2:9] = Array []
+  [7] Reassign mutate a$12_@3[5:8] = Array []
   [8] Goto bb1
 bb1:
   predecessor blocks: bb2 bb3
-  a$14_@1[2:9]: phi(bb2: a$11_@1, bb3: a$12_@1)
-  [9] Call read useFreeze$5(freeze a$14_@1)
-  [10] Call read useFreeze$5(read a$14_@1)
-  [11] Call mutate call$6_@3(read a$14_@1)
-  [12] Return read a$14_@1
+  a$14_@3[5:8]: phi(bb2: a$11_@3, bb3: a$12_@3)
+  [9] Call read useFreeze$5(freeze a$14_@3)
+  [10] Call read useFreeze$5(read a$14_@3)
+  [11] Call mutate call$6_@4(read a$14_@3)
+  [12] Return read a$14_@3
 scope0 [1:2]:
  - read props$7.cond
-scope1 [2:9]:
+scope1 [2:3]:
  - read props$7.x
- - read cond$8_@0
+scope3 [5:8]:
+ - read x$9_@1
 ```
 
 ### CFG
@@ -60,30 +61,30 @@ flowchart TB
   subgraph bb0
     bb0_instrs["
       [1] Const mutate cond$8_@0 = read props$7.cond
-      [2] Const mutate x$9_@1[2:9] = read props$7.x
+      [2] Const mutate x$9_@1 = read props$7.x
       [3] Let mutate a$10_@2 = undefined
     "]
     bb0_instrs --> bb0_terminal(["If (read cond$8_@0)"])
   end
   subgraph bb2
     bb2_instrs["
-      [5] Reassign mutate a$11_@1[2:9] = read x$9_@1
+      [5] Reassign mutate a$11_@3[5:8] = read x$9_@1
     "]
     bb2_instrs --> bb2_terminal(["Goto"])
   end
   subgraph bb3
     bb3_instrs["
-      [7] Reassign mutate a$12_@1[2:9] = Array []
+      [7] Reassign mutate a$12_@3[5:8] = Array []
     "]
     bb3_instrs --> bb3_terminal(["Goto"])
   end
   subgraph bb1
     bb1_instrs["
-      [9] Call read useFreeze$5(freeze a$14_@1)
-      [10] Call read useFreeze$5(read a$14_@1)
-      [11] Call mutate call$6_@3(read a$14_@1)
+      [9] Call read useFreeze$5(freeze a$14_@3)
+      [10] Call read useFreeze$5(read a$14_@3)
+      [11] Call mutate call$6_@4(read a$14_@3)
     "]
-    bb1_instrs --> bb1_terminal(["Return read a$14_@1"])
+    bb1_instrs --> bb1_terminal(["Return read a$14_@3"])
   end
 
   %% Jumps
diff --git a/compiler/forget/src/__tests__/fixtures/hir/logical-expression.expect.md b/compiler/forget/src/__tests__/fixtures/hir/logical-expression.expect.md
index 3ef91edbc8..c806987d47 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/logical-expression.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/logical-expression.expect.md
@@ -23,20 +23,20 @@ function g() {}
 
 ```
 bb0:
-  [1] Const mutate $5_@0[0:7] = Call mutate f$1_@0()
+  [1] Const mutate $5_@0[0:2] = Call mutate f$1_@0()
   [2] If (read $5_@0) then:bb2 else:bb3
 bb2:
   predecessor blocks: bb0
-  [3] Const mutate $6_@0[0:7] = Call mutate g$4_@0()
+  [3] Const mutate $6_@1[0:6] = Call mutate g$4_@1()
   [4] Goto bb1
 bb3:
   predecessor blocks: bb0
-  [5] Const mutate $7_@0[0:7] = read $5_@0
+  [5] Const mutate $7_@1[0:6] = read $5_@0
   [6] Goto bb1
 bb1:
   predecessor blocks: bb2 bb3
-  $8_@0[0:7]: phi(bb2: $6_@0, bb3: $7_@0)
-  [7] Return freeze $8_@0
+  $8_@1[0:6]: phi(bb2: $6_@1, bb3: $7_@1)
+  [7] Return freeze $8_@1
 
 ```
 
@@ -47,24 +47,24 @@ flowchart TB
   %% Basic Blocks
   subgraph bb0
     bb0_instrs["
-      [1] Const mutate $5_@0[0:7] = Call mutate f$1_@0()
+      [1] Const mutate $5_@0[0:2] = Call mutate f$1_@0()
     "]
     bb0_instrs --> bb0_terminal(["If (read $5_@0)"])
   end
   subgraph bb2
     bb2_instrs["
-      [3] Const mutate $6_@0[0:7] = Call mutate g$4_@0()
+      [3] Const mutate $6_@1[0:6] = Call mutate g$4_@1()
     "]
     bb2_instrs --> bb2_terminal(["Goto"])
   end
   subgraph bb3
     bb3_instrs["
-      [5] Const mutate $7_@0[0:7] = read $5_@0
+      [5] Const mutate $7_@1[0:6] = read $5_@0
     "]
     bb3_instrs --> bb3_terminal(["Goto"])
   end
   subgraph bb1
-    bb1_terminal(["Return freeze $8_@0"])
+    bb1_terminal(["Return freeze $8_@1"])
   end
 
   %% Jumps
@@ -91,20 +91,20 @@ function And$0() {
 
 ```
 bb0:
-  [1] Const mutate $5_@0[0:7] = Call mutate f$1_@0()
+  [1] Const mutate $5_@0[0:2] = Call mutate f$1_@0()
   [2] If (read $5_@0) then:bb2 else:bb3
 bb2:
   predecessor blocks: bb0
-  [3] Const mutate $6_@0[0:7] = read $5_@0
+  [3] Const mutate $6_@1[0:6] = read $5_@0
   [4] Goto bb1
 bb3:
   predecessor blocks: bb0
-  [5] Const mutate $7_@0[0:7] = Call mutate g$4_@0()
+  [5] Const mutate $7_@1[0:6] = Call mutate g$4_@1()
   [6] Goto bb1
 bb1:
   predecessor blocks: bb2 bb3
-  $8_@0[0:7]: phi(bb2: $6_@0, bb3: $7_@0)
-  [7] Return freeze $8_@0
+  $8_@1[0:6]: phi(bb2: $6_@1, bb3: $7_@1)
+  [7] Return freeze $8_@1
 
 ```
 
@@ -115,24 +115,24 @@ flowchart TB
   %% Basic Blocks
   subgraph bb0
     bb0_instrs["
-      [1] Const mutate $5_@0[0:7] = Call mutate f$1_@0()
+      [1] Const mutate $5_@0[0:2] = Call mutate f$1_@0()
     "]
     bb0_instrs --> bb0_terminal(["If (read $5_@0)"])
   end
   subgraph bb2
     bb2_instrs["
-      [3] Const mutate $6_@0[0:7] = read $5_@0
+      [3] Const mutate $6_@1[0:6] = read $5_@0
     "]
     bb2_instrs --> bb2_terminal(["Goto"])
   end
   subgraph bb3
     bb3_instrs["
-      [5] Const mutate $7_@0[0:7] = Call mutate g$4_@0()
+      [5] Const mutate $7_@1[0:6] = Call mutate g$4_@1()
     "]
     bb3_instrs --> bb3_terminal(["Goto"])
   end
   subgraph bb1
-    bb1_terminal(["Return freeze $8_@0"])
+    bb1_terminal(["Return freeze $8_@1"])
   end
 
   %% Jumps
@@ -159,23 +159,25 @@ function Or$0() {
 
 ```
 bb0:
-  [1] Const mutate $9_@0[0:9] = Call mutate f$2_@0()
+  [1] Const mutate $9_@0[0:2] = Call mutate f$2_@0()
   [2] Const mutate $10_@1 = null
-  [3] Const mutate $11_@0[0:9] = Binary read $9_@0 != read $10_@1
-  [4] If (read $11_@0) then:bb2 else:bb3
+  [3] Const mutate $11_@2 = Binary read $9_@0 != read $10_@1
+  [4] If (read $11_@2) then:bb2 else:bb3
 bb2:
   predecessor blocks: bb0
-  [5] Const mutate $12_@0[0:9] = read $9_@0
+  [5] Const mutate $12_@3[0:8] = read $9_@0
   [6] Goto bb1
 bb3:
   predecessor blocks: bb0
-  [7] Const mutate $13_@0[0:9] = Call mutate g$7_@0()
+  [7] Const mutate $13_@3[0:8] = Call mutate g$7_@3()
   [8] Goto bb1
 bb1:
   predecessor blocks: bb2 bb3
-  $14_@0[0:9]: phi(bb2: $12_@0, bb3: $13_@0)
-  [9] Return freeze $14_@0
-
+  $14_@3[0:8]: phi(bb2: $12_@3, bb3: $13_@3)
+  [9] Return freeze $14_@3
+scope2 [3:4]:
+ - read $9_@0
+ - read $10_@1
 ```
 
 ### CFG
@@ -185,26 +187,26 @@ flowchart TB
   %% Basic Blocks
   subgraph bb0
     bb0_instrs["
-      [1] Const mutate $9_@0[0:9] = Call mutate f$2_@0()
+      [1] Const mutate $9_@0[0:2] = Call mutate f$2_@0()
       [2] Const mutate $10_@1 = null
-      [3] Const mutate $11_@0[0:9] = Binary read $9_@0 != read $10_@1
+      [3] Const mutate $11_@2 = Binary read $9_@0 != read $10_@1
     "]
-    bb0_instrs --> bb0_terminal(["If (read $11_@0)"])
+    bb0_instrs --> bb0_terminal(["If (read $11_@2)"])
   end
   subgraph bb2
     bb2_instrs["
-      [5] Const mutate $12_@0[0:9] = read $9_@0
+      [5] Const mutate $12_@3[0:8] = read $9_@0
     "]
     bb2_instrs --> bb2_terminal(["Goto"])
   end
   subgraph bb3
     bb3_instrs["
-      [7] Const mutate $13_@0[0:9] = Call mutate g$7_@0()
+      [7] Const mutate $13_@3[0:8] = Call mutate g$7_@3()
     "]
     bb3_instrs --> bb3_terminal(["Goto"])
   end
   subgraph bb1
-    bb1_terminal(["Return freeze $14_@0"])
+    bb1_terminal(["Return freeze $14_@3"])
   end
 
   %% Jumps
diff --git a/compiler/forget/src/__tests__/fixtures/hir/ssa-if-else.expect.md b/compiler/forget/src/__tests__/fixtures/hir/ssa-if-else.expect.md
index 4a3465eb02..97a31f325a 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/ssa-if-else.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/ssa-if-else.expect.md
@@ -19,21 +19,25 @@ function foo() {
 
 ```
 bb0:
-  [1] Let mutate x$5_@0[1:8] = 1
+  [1] Let mutate x$5_@0 = 1
   [2] Let mutate y$6_@1 = 2
   [3] If (read y$6_@1) then:bb2 else:bb3
 bb2:
   predecessor blocks: bb0
-  [4] Let mutate z$7_@0[1:8] = Binary read x$5_@0 + read y$6_@1
+  [4] Let mutate z$7_@2 = Binary read x$5_@0 + read y$6_@1
   [5] Goto bb1
 bb3:
   predecessor blocks: bb0
-  [6] Let mutate z$8_@0[1:8] = read x$5_@0
+  [6] Let mutate z$8_@3 = read x$5_@0
   [7] Goto bb1
 bb1:
   predecessor blocks: bb2 bb3
   [8] Return
-
+scope2 [4:5]:
+ - read x$5_@0
+ - read y$6_@1
+scope3 [6:7]:
+ - read x$5_@0
 ```
 
 ### CFG
@@ -43,20 +47,20 @@ flowchart TB
   %% Basic Blocks
   subgraph bb0
     bb0_instrs["
-      [1] Let mutate x$5_@0[1:8] = 1
+      [1] Let mutate x$5_@0 = 1
       [2] Let mutate y$6_@1 = 2
     "]
     bb0_instrs --> bb0_terminal(["If (read y$6_@1)"])
   end
   subgraph bb2
     bb2_instrs["
-      [4] Let mutate z$7_@0[1:8] = Binary read x$5_@0 + read y$6_@1
+      [4] Let mutate z$7_@2 = Binary read x$5_@0 + read y$6_@1
     "]
     bb2_instrs --> bb2_terminal(["Goto"])
   end
   subgraph bb3
     bb3_instrs["
-      [6] Let mutate z$8_@0[1:8] = read x$5_@0
+      [6] Let mutate z$8_@3 = read x$5_@0
     "]
     bb3_instrs --> bb3_terminal(["Goto"])
   end