Index: flang/lib/Semantics/check-declarations.cpp
===================================================================
--- flang/lib/Semantics/check-declarations.cpp
+++ flang/lib/Semantics/check-declarations.cpp
@@ -46,6 +46,7 @@
   void Check(const ArraySpec &);
   void Check(const DeclTypeSpec &, bool canHaveAssumedTypeParameters);
   void Check(const Symbol &);
+  void CheckCommonBlock(const Symbol &);
   void Check(const Scope &);
   const Procedure *Characterize(const Symbol &);
 
@@ -375,6 +376,8 @@
   }
 }
 
+void CheckHelper::CheckCommonBlock(const Symbol &symbol) { CheckBindC(symbol); }
+
 void CheckHelper::CheckValue(
     const Symbol &symbol, const DerivedTypeSpec *derived) { // C863 - C865
   if (!IsDummy(symbol)) {
@@ -1729,6 +1732,9 @@
     for (const auto &pair : scope) {
       Check(*pair.second);
     }
+    for (const auto &pair : scope.commonBlocks()) {
+      CheckCommonBlock(*pair.second);
+    }
     int mainProgCnt{0};
     for (const Scope &child : scope.children()) {
       Check(child);
@@ -1865,7 +1871,7 @@
   const auto *subp{symbol.detailsIf<SubprogramDetails>()};
   if ((subp && !subp->isInterface() &&
           ClassifyProcedure(symbol) != ProcedureDefinitionClass::Internal) ||
-      symbol.has<ObjectEntityDetails>()) {
+      symbol.has<ObjectEntityDetails>() || symbol.has<CommonBlockDetails>()) {
     // Symbol defines data or entry point
     return symbol.GetBindName();
   } else {
@@ -1887,7 +1893,7 @@
     if (!pair.second) {
       const Symbol &other{*pair.first->second};
       if (DefinesBindCName(other) && !context_.HasError(other)) {
-        if (auto *msg{messages_.Say(
+        if (auto *msg{messages_.Say(symbol.name(),
                 "Two symbols have the same BIND(C) name '%s'"_err_en_US,
                 *name)}) {
           msg->Attach(other.name(), "Conflicting symbol"_en_US);
Index: flang/lib/Semantics/resolve-names.cpp
===================================================================
--- flang/lib/Semantics/resolve-names.cpp
+++ flang/lib/Semantics/resolve-names.cpp
@@ -1674,7 +1674,19 @@
   } else {
     label = parser::ToLowerCaseLetters(symbol.name().ToString());
   }
+  // Check if a symbol has two Bind names.
+  std::string oldBindName;
+  if (symbol.GetBindName()) {
+    oldBindName = *symbol.GetBindName();
+  }
   symbol.SetBindName(std::move(*label));
+  if (!oldBindName.empty()) {
+    if (const std::string * newBindName{symbol.GetBindName()}) {
+      if (oldBindName.compare(*newBindName) != 0) {
+        Say(symbol.name(), "The entity '%s' has multiple BIND names"_err_en_US);
+      }
+    }
+  }
 }
 
 void AttrsVisitor::Post(const parser::LanguageBindingSpec &x) {
Index: flang/test/Semantics/declarations03.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/declarations03.f90
@@ -0,0 +1,50 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+! test bind(c) name conflict
+
+module m
+
+  integer :: x, y, z, w, i, j, k
+
+  !ERROR: Two symbols have the same BIND(C) name 'aa'
+  common /blk1/ x, /blk2/ y
+  bind(c, name="aa") :: /blk1/, /blk2/
+
+  integer :: t
+  !ERROR: Two symbols have the same BIND(C) name 'bb'
+  common /blk3/ z
+  bind(c, name="bb") :: /blk3/, t
+
+  integer :: t2
+  !ERROR: Two symbols have the same BIND(C) name 'cc'
+  common /blk4/ w
+  bind(c, name="cc") :: t2, /blk4/
+
+  !ERROR: The entity 'blk5' has multiple BIND names
+  common /blk5/ i
+  bind(c, name="dd") :: /blk5/
+  bind(c, name="ee") :: /blk5/
+
+  !ERROR: Two symbols have the same BIND(C) name 'ff'
+  common /blk6/ j, /blk7/ k
+  bind(c, name="ff") :: /blk6/
+  bind(c, name="ff") :: /blk7/
+
+  !ERROR: The entity 's1' has multiple BIND names
+  integer :: s1
+  bind(c, name="gg") :: s1
+  bind(c, name="hh") :: s1
+
+  !ERROR: Two symbols have the same BIND(C) name 'ii'
+  integer :: s2, s3
+  bind(c, name="ii") :: s2
+  bind(c, name="ii") :: s3
+
+  !ERROR: The entity 's4' has multiple BIND names
+  integer, bind(c, name="ss1") :: s4
+  bind(c, name="jj") :: s4
+
+  !ERROR: The entity 's5' has multiple BIND names
+  bind(c, name="kk") :: s5
+  integer, bind(c, name="ss2") :: s5
+
+end