diff --git a/Test/400.tese b/Test/400.tese
index e953ab5f..3e913e87 100644
--- a/Test/400.tese
+++ b/Test/400.tese
@@ -97,3 +97,5 @@ layout(location = 24) in vec4 ivlc[];  // ERROR
 
 layout(location = 23) out vec4 ovla[2];
 layout(location = 24) out vec4 ovlb[2];  // ERROR
+
+in float gl_TessLevelOuter[4];           // ERROR
diff --git a/Test/baseResults/150.tesc.out b/Test/baseResults/150.tesc.out
index 35c0848d..003179ec 100644
--- a/Test/baseResults/150.tesc.out
+++ b/Test/baseResults/150.tesc.out
@@ -388,7 +388,8 @@ ERROR: 0:78: 'in' : type must be an array: bla
 ERROR: 0:86: '[]' : tessellation input array size must be gl_MaxPatchVertices or implicitly sized 
 ERROR: 0:96: 'location' : overlapping use of location 24
 ERROR: 0:99: 'location' : overlapping use of location 24
-ERROR: 29 compilation errors.  No code generated.
+ERROR: 0:101: 'gl_TessLevelOuter' : identifiers starting with "gl_" are reserved 
+ERROR: 30 compilation errors.  No code generated.
 
 
 Shader version: 400
diff --git a/Test/baseResults/400.tese.out b/Test/baseResults/400.tese.out
index 6cad8dd9..1b436625 100644
--- a/Test/baseResults/400.tese.out
+++ b/Test/baseResults/400.tese.out
@@ -29,7 +29,8 @@ ERROR: 0:78: 'in' : type must be an array: bla
 ERROR: 0:86: '[]' : tessellation input array size must be gl_MaxPatchVertices or implicitly sized 
 ERROR: 0:96: 'location' : overlapping use of location 24
 ERROR: 0:99: 'location' : overlapping use of location 24
-ERROR: 29 compilation errors.  No code generated.
+ERROR: 0:101: 'gl_TessLevelOuter' : identifiers starting with "gl_" are reserved 
+ERROR: 30 compilation errors.  No code generated.
 
 
 Shader version: 400
diff --git a/glslang/MachineIndependent/ParseHelper.cpp b/glslang/MachineIndependent/ParseHelper.cpp
index b778d18e..ab9938bf 100644
--- a/glslang/MachineIndependent/ParseHelper.cpp
+++ b/glslang/MachineIndependent/ParseHelper.cpp
@@ -2213,6 +2213,11 @@ void TParseContext::declareArray(TSourceLoc loc, TString& identifier, const TTyp
     if (! symbol) {
         bool currentScope;
         symbol = symbolTable.find(identifier, 0, &currentScope);
+
+        if (symbol && builtInName(identifier) && ! symbolTable.atBuiltInLevel()) {
+            // bad shader (errors already reported) trying to redeclare a built-in name as an array
+            return;
+        }
         if (symbol == 0 || ! currentScope) {
             //
             // Successfully process a new definition.