Fix issue with multiple namespace openings (#2176)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Added sample-grad-clamp-lod sample.

* Fix handling multiple reopenings of namespaces.

4 files changed, 76 insertions, 12 deletions

diff --git a/source/slang/slang-ast-support-types.h b/source/slang/slang-ast-support-types.h
index e7c2287ff..ffe7cd553 100644
--- a/source/slang/slang-ast-support-types.h
+++ b/source/slang/slang-ast-support-types.h
@@ -310,6 +310,9 @@ namespace Slang
         template<typename T>
         bool hasModifier() { return findModifier<T>() != nullptr; }
 
+            /// True if has no modifiers
+        bool isEmpty() const { return first == nullptr; }
+
         FilteredModifierList<Modifier>::Iterator begin() { return FilteredModifierList<Modifier>::Iterator(first); }
         FilteredModifierList<Modifier>::Iterator end() { return FilteredModifierList<Modifier>::Iterator(nullptr); }
     };
diff --git a/source/slang/slang-parser.cpp b/source/slang/slang-parser.cpp
index 961691c9a..c08f5cf34 100644
--- a/source/slang/slang-parser.cpp
+++ b/source/slang/slang-parser.cpp
@@ -2928,8 +2928,7 @@ namespace Slang
         // any non-null pointer we return to the AST).
         //
         NamespaceDecl* namespaceDecl = nullptr;
-        NodeBase* result = nullptr;
-        //
+
         // In order to find out what case we are in, we start by looking
         // for a namespace declaration of the same name in the parent
         // declaration.
@@ -2985,14 +2984,6 @@ namespace Slang
             {
                 namespaceDecl = parser->astBuilder->create<NamespaceDecl>();
                 namespaceDecl->nameAndLoc = nameAndLoc;
-
-                // In the case where we are creating the first
-                // declaration of the given namesapce, we need
-                // to use it as the return value of the parsing
-                // callback, so that it is appropriately added
-                // to the parent declaration.
-                //
-                result = namespaceDecl;
             }
         }
 
@@ -3003,7 +2994,7 @@ namespace Slang
         //
         parseDeclBody(parser, namespaceDecl);
 
-        return result;
+        return namespaceDecl;
     }
 
     static NodeBase* parseUsingDecl(Parser* parser, void* /*userData*/)
@@ -3590,6 +3581,16 @@ namespace Slang
         ContainerDecl*		containerDecl,
         Modifiers			modifiers)
     {
+
+        // If this is a namespace and already added, we don't want to add to the parent
+        // Or add any modifiers
+        if (as<NamespaceDecl>(decl) && decl->parentDecl)
+        {
+            // Presumably we have no modifiers.
+            SLANG_ASSERT(modifiers.isEmpty());
+            return;
+        }
+
         // Add any modifiers we parsed before the declaration to the list
         // of modifiers on the declaration itself.
         //
@@ -3601,9 +3602,9 @@ namespace Slang
             declToModify = genericDecl->inner;
         _addModifiers(declToModify, modifiers);
 
-        // Make sure the decl is properly nested inside its lexical parent
         if (containerDecl)
         {
+            // Make sure the decl is properly nested inside its lexical parent
             AddMember(containerDecl, decl);
         }
     }
diff --git a/tests/language-feature/namespaces/multiple-namespace.slang b/tests/language-feature/namespaces/multiple-namespace.slang
new file mode 100644
index 000000000..a687d5e79
--- /dev/null
+++ b/tests/language-feature/namespaces/multiple-namespace.slang
@@ -0,0 +1,56 @@
+// multiple-namespace.slang
+
+//TEST(compute):COMPARE_COMPUTE: -shaderobj
+
+// Multiple namespace open/closing
+
+namespace A
+{
+    struct Struct1
+    {
+        int a;
+    }
+}
+
+namespace A
+{
+    struct Struct2
+    {
+        int b;
+    }
+}
+
+namespace A
+{
+    struct Struct3
+    {
+        int c;
+    }
+}
+   
+// A few more 
+
+namespace A {}
+namespace A {}
+namespace A { namespace A {} }
+   
+int test(int val)
+{
+    A.Struct1 s1 = {};
+    A::Struct2 s2 = { val };
+    A.Struct3 s3 = { val * val };
+    
+    return s1.a + s2.b + s3.c;
+}
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    uint tid = dispatchThreadID.x;
+    int inVal = tid;
+    int outVal = test(inVal);
+    outputBuffer[tid] = outVal;
+}
diff --git a/tests/language-feature/namespaces/multiple-namespace.slang.expected.txt b/tests/language-feature/namespaces/multiple-namespace.slang.expected.txt
new file mode 100644
index 000000000..bfb7eefe7
--- /dev/null
+++ b/tests/language-feature/namespaces/multiple-namespace.slang.expected.txt
@@ -0,0 +1,4 @@
+0
+2
+6
+C