5 files changed, 46 insertions, 9 deletions
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 54723369002..53a4a4c7834 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -4395,8 +4395,13 @@ Sema::CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
     if (VK != VK_RValue)
       OK = OK_VectorComponent;
 
-    // FIXME: need to deal with const...
     ResultType = VTy->getElementType();
+    QualType BaseType = BaseExpr->getType();
+    Qualifiers BaseQuals = BaseType.getQualifiers();
+    Qualifiers MemberQuals = ResultType.getQualifiers();
+    Qualifiers Combined = BaseQuals + MemberQuals;
+    if (Combined != MemberQuals)
+      ResultType = Context.getQualifiedType(ResultType, Combined);
   } else if (LHSTy->isArrayType()) {
     // If we see an array that wasn't promoted by
     // DefaultFunctionArrayLvalueConversion, it must be an array that
@@ -10434,8 +10439,16 @@ static void DiagnoseConstAssignment(Sema &S, const Expr *E,
         // Static fields do not inherit constness from parents.
         break;
       }
-      break;
-    } // End MemberExpr
+      break; // End MemberExpr
+    } else if (const ArraySubscriptExpr *ASE =
+                   dyn_cast<ArraySubscriptExpr>(E)) {
+      E = ASE->getBase()->IgnoreParenImpCasts();
+      continue;
+    } else if (const ExtVectorElementExpr *EVE =
+                   dyn_cast<ExtVectorElementExpr>(E)) {
+      E = EVE->getBase()->IgnoreParenImpCasts();
+      continue;
+    }
     break;
   }
 
diff --git a/clang/lib/Sema/SemaExprMember.cpp b/clang/lib/Sema/SemaExprMember.cpp
index f57f79e62ef..5bb9653db08 100644
--- a/clang/lib/Sema/SemaExprMember.cpp
+++ b/clang/lib/Sema/SemaExprMember.cpp
@@ -1623,10 +1623,14 @@ static ExprResult LookupMemberExpr(Sema &S, LookupResult &R,
       else
         VK = BaseExpr.get()->getValueKind();
     }
+
     QualType ret = CheckExtVectorComponent(S, BaseType, VK, OpLoc,
                                            Member, MemberLoc);
     if (ret.isNull())
       return ExprError();
+    Qualifiers BaseQ =
+        S.Context.getCanonicalType(BaseExpr.get()->getType()).getQualifiers();
+    ret = S.Context.getQualifiedType(ret, BaseQ);
 
     return new (S.Context)
         ExtVectorElementExpr(ret, VK, BaseExpr.get(), *Member, MemberLoc);
diff --git a/clang/test/Sema/assign.c b/clang/test/Sema/assign.c
index 5bdfa9a3a5d..28d7b9f3bbd 100644
--- a/clang/test/Sema/assign.c
+++ b/clang/test/Sema/assign.c
@@ -11,10 +11,10 @@ void test2 (const struct {int a;} *x) {
 
 typedef int arr[10];
 void test3() {
-  const arr b;
-  const int b2[10]; 
-  b[4] = 1; // expected-error {{read-only variable is not assignable}}
-  b2[4] = 1; // expected-error {{read-only variable is not assignable}}
+  const arr b;      // expected-note {{variable 'b' declared const here}}
+  const int b2[10]; // expected-note {{variable 'b2' declared const here}}
+  b[4] = 1;         // expected-error {{cannot assign to variable 'b' with const-qualified type 'const arr' (aka 'int const[10]')}}
+  b2[4] = 1;        // expected-error {{cannot assign to variable 'b2' with const-qualified type 'const int [10]'}}
 }
 
 typedef struct I {
diff --git a/clang/test/Sema/typedef-retain.c b/clang/test/Sema/typedef-retain.c
index d216466360b..3d784ce60a7 100644
--- a/clang/test/Sema/typedef-retain.c
+++ b/clang/test/Sema/typedef-retain.c
@@ -16,8 +16,8 @@ void test2(float4 a, int4p result, int i) {
 typedef int a[5];
 void test3() {
   typedef const a b;
-  b r;
-  r[0]=10;  // expected-error {{read-only variable is not assignable}}
+  b r;       // expected-note {{variable 'r' declared const here}}
+  r[0] = 10; // expected-error {{cannot assign to variable 'r' with const-qualified type 'b' (aka 'int const[5]')}}
 }
 
 int test4(const a y) {
diff --git a/clang/test/SemaCXX/err_typecheck_assign_const.cpp b/clang/test/SemaCXX/err_typecheck_assign_const.cpp
index 7e281256514..3725e58b422 100644
--- a/clang/test/SemaCXX/err_typecheck_assign_const.cpp
+++ b/clang/test/SemaCXX/err_typecheck_assign_const.cpp
@@ -129,3 +129,23 @@ void test() {
   Func &bar();
   bar()() = 0; // expected-error {{read-only variable is not assignable}}
 }
+
+typedef float float4 __attribute__((ext_vector_type(4)));
+struct OhNo {
+  float4 v;
+  void AssignMe() const { v.x = 1; } // expected-error {{cannot assign to non-static data member within const member function 'AssignMe'}} \
+                                        expected-note {{member function 'OhNo::AssignMe' is declared const here}}
+};
+
+typedef float float4_2 __attribute__((__vector_size__(16)));
+struct OhNo2 {
+  float4_2 v;
+  void AssignMe() const { v[0] = 1; } // expected-error {{cannot assign to non-static data member within const member function 'AssignMe'}} \
+                                        expected-note {{member function 'OhNo2::AssignMe' is declared const here}}
+};
+
+struct OhNo3 {
+  float v[4];
+  void AssignMe() const { v[0] = 1; } // expected-error {{cannot assign to non-static data member within const member function 'AssignMe'}} \
+                                        expected-note {{member function 'OhNo3::AssignMe' is declared const here}}
+};