Steps to reproduce:
1. Create new Unity project using High Definition 3D Template
2. In Project window create Blank Shader Graph
3. Open Shader Graph Asset
4. In Graph Inspector window > Active Targets select HDRP
5. Observe the Console window

Actual results: “Shader error in 'Shader Graphs/Master’:” error and “Shader warning in 'Shader Graphs/Master': implicit truncation of vector type at /(1105) (on metal)” warnings are thrown in the Console after adding HDRP as an Active Target
Expected results: No warnings or errors should be thrown in the Console

Reproducible with versions: 6000.0.66f1, 6000.3.5f1, 6000.4.0b5, 6000.5.0a5

Tested on (OS): macOS Silicon Tahoe 26.2 (M1)

Error/warnings:
{code:java}
Shader error in 'Shader Graphs/Master': undeclared identifier 'UnpackVaryingsMeshToFragInputs' at (209)/Library/PackageCache/com.unity.render-pipelines.high-definition@d4532d6af4d6/Runtime/RenderPipeline/ShaderPass/VertMesh.hlsl(47) (on metal)

Compiling Subshader: 0, Pass: GBuffer, Vertex program with <no keywords>
Platform defines: SHADER_API_DESKTOP UNITY_ENABLE_DETAIL_NORMALMAP UNITY_ENABLE_REFLECTION_BUFFERS UNITY_FRAMEBUFFER_FETCH_AVAILABLE UNITY_LIGHTMAP_FULL_HDR UNITY_LIGHT_PROBE_PROXY_VOLUME UNITY_NEEDS_RENDERPASS_FBFETCH_FALLBACK UNITY_PBS_USE_BRDF1 UNITY_SPECCUBE_BLENDING UNITY_SPECCUBE_BOX_PROJECTION UNITY_USE_DITHER_MASK_FOR_ALPHABLENDED_SHADOWS
Disabled keywords: DEBUG_DISPLAY DIRLIGHTMAP_COMBINED DOTS_INSTANCING_ON DYNAMICLIGHTMAP_ON INSTANCING_ON LIGHTMAP_ON SHADER_API_GLES30 SHADER_API_GLES31 SHADER_API_GLES32 UNITY_ASTC_NORMALMAP_ENCODING UNITY_COLORSPACE_GAMMA UNITY_HARDWARE_TIER1 UNITY_HARDWARE_TIER2 UNITY_HARDWARE_TIER3 UNITY_LIGHTMAP_DLDR_ENCODING UNITY_LIGHTMAP_RGBM_ENCODING UNITY_METAL_SHADOWS_USE_POINT_FILTERING UNITY_NO_DXT5nm UNITY_NO_SCREENSPACE_SHADOWS UNITY_PBS_USE_BRDF2 UNITY_PBS_USE_BRDF3 UNITY_PRETRANSFORM_TO_DISPLAY_ORIENTATION UNITY_UNIFIED_SHADER_PRECISION_MODEL UNITY_VIRTUAL_TEXTURING USE_LEGACY_LIGHTMAPS _DOUBLESIDED_ON _REFRACTION_PLANE _REFRACTION_SPHERE _REFRACTION_THIN _SURFACE_TYPE_TRANSPARENT
{code}

{code:java}
Shader warning in 'Shader Graphs/Master': implicit truncation of vector type at /(1107) (on metal)
Compiling Subshader: 0, Pass: DepthOnly, Vertex program with <no keywords>
Platform defines: SHADER_API_DESKTOP UNITY_ENABLE_DETAIL_NORMALMAP UNITY_ENABLE_REFLECTION_BUFFERS UNITY_FRAMEBUFFER_FETCH_AVAILABLE UNITY_LIGHTMAP_FULL_HDR UNITY_LIGHT_PROBE_PROXY_VOLUME UNITY_NEEDS_RENDERPASS_FBFETCH_FALLBACK UNITY_PBS_USE_BRDF1 UNITY_SPECCUBE_BLENDING UNITY_SPECCUBE_BOX_PROJECTION UNITY_USE_DITHER_MASK_FOR_ALPHABLENDED_SHADOWS
{code}