Disallow case statements nested in blocks

src/compiler/translator/ValidateSwitch.cpp

@@ -26,7 +26,7 @@ class ValidateSwitch : public TIntermTraverser
     void visitSymbol(TIntermSymbol *) override;
     void visitConstantUnion(TIntermConstantUnion *) override;
     bool visitDeclaration(Visit, TIntermDeclaration *) override;
-    bool visitBlock(Visit, TIntermBlock *) override;
+    bool visitBlock(Visit visit, TIntermBlock *) override;
     bool visitBinary(Visit, TIntermBinary *) override;
     bool visitUnary(Visit, TIntermUnary *) override;
     bool visitTernary(Visit, TIntermTernary *) override;
@@ -107,13 +107,17 @@ bool ValidateSwitch::visitDeclaration(Visit, TIntermDeclaration *)
     return true;
 }
 
-bool ValidateSwitch::visitBlock(Visit, TIntermBlock *)
+bool ValidateSwitch::visitBlock(Visit visit, TIntermBlock *)
 {
     if (getParentNode() != nullptr)
     {
         if (!mFirstCaseFound)
             mStatementBeforeCase = true;
         mLastStatementWasCase    = false;
+        if (visit == PreVisit)
+            ++mControlFlowDepth;
+        if (visit == PostVisit)
+            --mControlFlowDepth;
     }
     return true;
 }

src/tests/compiler_tests/ShaderValidation_test.cpp

@@ -5939,3 +5939,31 @@ TEST_F(FragmentShaderValidationTest, DeclareBothBuiltInFragmentOutputsInvariant)
         FAIL() << "Shader compilation failed, expecting success:\n" << mInfoLog;
     }
 }
+
+// Test that a case cannot be placed inside a block nested inside a switch statement. GLSL ES 3.10
+// section 6.2.
+TEST_F(FragmentShaderValidationTest, CaseInsideBlock)
+{
+    const std::string &shaderString =
+        R"(#version 300 es
+        precision mediump float;
+        uniform int u;
+        out vec4 my_FragColor;
+        void main()
+        {
+            switch (u)
+            {
+                case 1:
+                {
+                    case 0:
+                        my_FragColor = vec4(0.0);
+                }
+                default:
+                    my_FragColor = vec4(1.0);
+            }
+        })";
+    if (compile(shaderString))
+    {
+        FAIL() << "Shader compilation succeeded, expecting failure:\n" << mInfoLog;
+    }
+}