diff --git a/llvm/include/llvm/Support/FileCheck.h b/llvm/include/llvm/Support/FileCheck.h
--- a/llvm/include/llvm/Support/FileCheck.h
+++ b/llvm/include/llvm/Support/FileCheck.h
@@ -115,13 +115,12 @@
   /// \returns this variable's value.
   Optional<uint64_t> getValue() const { return Value; }
 
-  /// Sets value of this numeric variable, if undefined. Triggers an assertion
-  /// failure if the variable is actually defined.
-  void setValue(uint64_t Value);
+  /// Sets value of this numeric variable to \p NewValue.
+  void setValue(uint64_t NewValue) { Value = NewValue; }
 
   /// Clears value of this numeric variable, regardless of whether it is
   /// currently defined or not.
-  void clearValue();
+  void clearValue() { Value = None; }
 
   /// \returns the line number where this variable is defined, if any, or None
   /// if defined before input is parsed.
diff --git a/llvm/lib/Support/FileCheck.cpp b/llvm/lib/Support/FileCheck.cpp
--- a/llvm/lib/Support/FileCheck.cpp
+++ b/llvm/lib/Support/FileCheck.cpp
@@ -24,17 +24,6 @@
 
 using namespace llvm;
 
-void FileCheckNumericVariable::setValue(uint64_t NewValue) {
-  assert(!Value && "Overwriting numeric variable's value is not allowed");
-  Value = NewValue;
-}
-
-void FileCheckNumericVariable::clearValue() {
-  if (!Value)
-    return;
-  Value = None;
-}
-
 Expected<uint64_t> FileCheckNumericVariableUse::eval() const {
   Optional<uint64_t> Value = NumericVariable->getValue();
   if (Value)
@@ -631,10 +620,8 @@
     for (const auto &Substitution : Substitutions) {
       // Substitute and check for failure (e.g. use of undefined variable).
       Expected<std::string> Value = Substitution->getResult();
-      if (!Value) {
-        Context->LineVariable->clearValue();
+      if (!Value)
         return Value.takeError();
-      }
 
       // Plop it into the regex at the adjusted offset.
       TmpStr.insert(TmpStr.begin() + Substitution->getIndex() + InsertOffset,
@@ -644,7 +631,6 @@
 
     // Match the newly constructed regex.
     RegExToMatch = TmpStr;
-    Context->LineVariable->clearValue();
   }
 
   SmallVector<StringRef, 4> MatchInfo;
diff --git a/llvm/test/FileCheck/line-count.txt b/llvm/test/FileCheck/line-count.txt
--- a/llvm/test/FileCheck/line-count.txt
+++ b/llvm/test/FileCheck/line-count.txt
@@ -55,12 +55,18 @@
 55 BAD11: [[@LINE-1x]]
 56 ERR11: line-count.txt:[[#@LINE-1]]:20: error: unexpected characters at end of expression 'x'
 57
-58 CHECK: [[#@LINE]] CHECK
-59 CHECK: [[# @LINE]] CHECK
-60 CHECK: [[# @LINE ]] CHECK
-61
-62 CHECK: [[#@LINE-1]]
-63 CHECK: [[# @LINE-1]] CHECK
-64 CHECK: [[# @LINE -1]] CHECK
-65 CHECK: [[# @LINE - 1]] CHECK
-66 CHECK: [[# @LINE - 1 ]] CHECK
+; RUN: not FileCheck -check-prefix BAD12 -input-file %s %s 2>&1 \
+; RUN:   | FileCheck -check-prefix ERR12 %s
+60
+61 BAD12: [[#@LINE-1]] NOT HERE
+62 ERR12: note: with "@LINE-1" equal to "60"
+63
+64 CHECK: [[#@LINE]] CHECK
+65 CHECK: [[# @LINE]] CHECK
+66 CHECK: [[# @LINE ]] CHECK
+67
+68 CHECK: [[#@LINE-1]]
+69 CHECK: [[# @LINE-1]] CHECK
+70 CHECK: [[# @LINE -1]] CHECK
+71 CHECK: [[# @LINE - 1]] CHECK
+72 CHECK: [[# @LINE - 1 ]] CHECK
diff --git a/llvm/test/FileCheck/numeric-expression.txt b/llvm/test/FileCheck/numeric-expression.txt
--- a/llvm/test/FileCheck/numeric-expression.txt
+++ b/llvm/test/FileCheck/numeric-expression.txt
@@ -4,7 +4,7 @@
 
 ; Numeric variable definition without spaces.
 DEF NO SPC
-11
+10
 CHECK-LABEL: DEF NO SPC
 CHECK-NEXT: [[#VAR1:]]
 
@@ -18,6 +18,12 @@
 CHECK-NEXT: [[# VAR1b :]]
 CHECK-NEXT: [[# VAR1c : ]]
 
+; Numeric variable redefinition.
+REDEF NO SPC
+11
+CHECK-LABEL: REDEF
+CHECK-NEXT: [[#VAR1:]]
+
 ; Numeric expressions using variables defined on other lines without spaces.
 USE NO SPC
 11
diff --git a/llvm/unittests/Support/FileCheckTest.cpp b/llvm/unittests/Support/FileCheckTest.cpp
--- a/llvm/unittests/Support/FileCheckTest.cpp
+++ b/llvm/unittests/Support/FileCheckTest.cpp
@@ -55,7 +55,7 @@
 
 TEST_F(FileCheckTest, NumericVariable) {
   // Undefined variable: getValue and eval fail, error returned by eval holds
-  // the name of the undefined variable and setValue does not trigger assert.
+  // the name of the undefined variable.
   FileCheckNumericVariable FooVar = FileCheckNumericVariable("FOO", 1);
   EXPECT_EQ("FOO", FooVar.getName());
   FileCheckNumericVariableUse FooVarUse =
@@ -64,6 +64,7 @@
   Expected<uint64_t> EvalResult = FooVarUse.eval();
   EXPECT_FALSE(EvalResult);
   expectUndefError("FOO", EvalResult.takeError());
+
   FooVar.setValue(42);
 
   // Defined variable: getValue and eval return value set.