video_core/shader: Resolve instances of variable shadowing

Silences a few -Wshadow warnings.

src/video_core/shader/decode/arithmetic_integer.cpp

@@ -144,7 +144,7 @@ u32 ShaderIR::DecodeArithmeticInteger(NodeBlock& bb, u32 pc) {
     case OpCode::Id::ICMP_IMM: {
         const Node zero = Immediate(0);
 
-        const auto [op_b, test] = [&]() -> std::pair<Node, Node> {
+        const auto [op_rhs, test] = [&]() -> std::pair<Node, Node> {
             switch (opcode->get().GetId()) {
             case OpCode::Id::ICMP_CR:
                 return {GetConstBuffer(instr.cbuf34.index, instr.cbuf34.offset),
@@ -161,10 +161,10 @@ u32 ShaderIR::DecodeArithmeticInteger(NodeBlock& bb, u32 pc) {
                 return {zero, zero};
             }
         }();
-        const Node op_a = GetRegister(instr.gpr8);
+        const Node op_lhs = GetRegister(instr.gpr8);
         const Node comparison =
             GetPredicateComparisonInteger(instr.icmp.cond, instr.icmp.is_signed != 0, test, zero);
-        SetRegister(bb, instr.gpr0, Operation(OperationCode::Select, comparison, op_a, op_b));
+        SetRegister(bb, instr.gpr0, Operation(OperationCode::Select, comparison, op_lhs, op_rhs));
         break;
     }
     case OpCode::Id::LOP_C:

src/video_core/shader/decode/image.cpp

@@ -144,8 +144,8 @@ u32 ShaderIR::DecodeImage(NodeBlock& bb, u32 pc) {
 
 Image& ShaderIR::GetImage(Tegra::Shader::Image image, Tegra::Shader::ImageType type) {
     const auto offset{static_cast<std::size_t>(image.index.Value())};
-    if (const auto image = TryUseExistingImage(offset, type)) {
+    if (const auto existing_image = TryUseExistingImage(offset, type)) {
-        return *image;
+        return *existing_image;
     }
 
     const std::size_t next_index{used_images.size()};

src/video_core/shader/decode/other.cpp

@@ -67,7 +67,7 @@ u32 ShaderIR::DecodeOther(NodeBlock& bb, u32 pc) {
         break;
     }
     case OpCode::Id::MOV_SYS: {
-        const Node value = [&]() {
+        const Node value = [this, instr] {
             switch (instr.sys20) {
             case SystemVariable::Ydirection:
                 return Operation(OperationCode::YNegate);

src/video_core/shader/decode/shift.cpp

@@ -18,7 +18,7 @@ u32 ShaderIR::DecodeShift(NodeBlock& bb, u32 pc) {
     const auto opcode = OpCode::Decode(instr);
 
     Node op_a = GetRegister(instr.gpr8);
-    Node op_b = [&]() {
+    Node op_b = [this, instr] {
         if (instr.is_b_imm) {
             return Immediate(instr.alu.GetSignedImm20_20());
         } else if (instr.is_b_gpr) {

src/video_core/shader/decode/video.cpp

@@ -23,7 +23,7 @@ u32 ShaderIR::DecodeVideo(NodeBlock& bb, u32 pc) {
     const Node op_a =
         GetVideoOperand(GetRegister(instr.gpr8), instr.video.is_byte_chunk_a, instr.video.signed_a,
                         instr.video.type_a, instr.video.byte_height_a);
-    const Node op_b = [&]() {
+    const Node op_b = [this, instr] {
         if (instr.video.use_register_b) {
             return GetVideoOperand(GetRegister(instr.gpr20), instr.video.is_byte_chunk_b,
                                    instr.video.signed_b, instr.video.type_b,

src/video_core/shader/decode/warp.cpp

@@ -46,9 +46,10 @@ u32 ShaderIR::DecodeWarp(NodeBlock& bb, u32 pc) {
         break;
     }
     case OpCode::Id::SHFL: {
+        Node width = [this, instr] {
             Node mask = instr.shfl.is_mask_imm ? Immediate(static_cast<u32>(instr.shfl.mask_imm))
                                                : GetRegister(instr.gpr39);
-        Node width = [&] {
+
             // Convert the obscure SHFL mask back into GL_NV_shader_thread_shuffle's width. This has
             // been done reversing Nvidia's math. It won't work on all cases due to SHFL having
             // different parameters that don't properly map to GLSL's interface, but it should work