diff --git a/clang-tools-extra/clang-tidy/utils/LexerUtils.h b/clang-tools-extra/clang-tidy/utils/LexerUtils.h
--- a/clang-tools-extra/clang-tidy/utils/LexerUtils.h
+++ b/clang-tools-extra/clang-tidy/utils/LexerUtils.h
@@ -10,6 +10,7 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_UTILS_LEXER_UTILS_H
 
 #include "clang/AST/ASTContext.h"
+#include "clang/Basic/TokenKinds.h"
 #include "clang/Lex/Lexer.h"
 
 namespace clang {
@@ -70,6 +71,11 @@
     if (PotentialMatch.isOneOf(TK, TKs...))
       return PotentialMatch.getLocation();
 
+    // If we reach the end of the file, and eof is not the target token, we stop
+    // the loop, otherwise we will get infinite loop (findNextToken will return
+    // eof on eof).
+    if (PotentialMatch.is(tok::eof))
+      return SourceLocation();
     Start = PotentialMatch.getLastLoc();
   }
 }
diff --git a/clang-tools-extra/test/clang-tidy/readability-isolate-declaration-no-infinite-loop.cpp b/clang-tools-extra/test/clang-tidy/readability-isolate-declaration-no-infinite-loop.cpp
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/readability-isolate-declaration-no-infinite-loop.cpp
@@ -0,0 +1,7 @@
+// RUN: %check_clang_tidy -expect-clang-tidy-error %s readability-isolate-declaration %t
+
+int main(){
+  int a, b
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: multiple declarations in a single statement reduces readability
+  // CHECK-MESSAGES: [[@LINE-2]]:11: error: expected ';' at end of declaration [clang-diagnostic-error]
+}