src/tint/lang/wgsl/resolver/dual_source_blending_extension_test.cc - tint - Git at Google

 // Copyright 2023 The Dawn & Tint Authors
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are met:
 //
 // 1. Redistributions of source code must retain the above copyright notice, this
 //    list of conditions and the following disclaimer.
 //
 // 2. Redistributions in binary form must reproduce the above copyright notice,
 //    this list of conditions and the following disclaimer in the documentation
 //    and/or other materials provided with the distribution.
 //
 // 3. Neither the name of the copyright holder nor the names of its
 //    contributors may be used to endorse or promote products derived from
 //    this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 #include "src/tint/lang/core/fluent_types.h"
 #include "src/tint/lang/wgsl/resolver/resolver.h"
 #include "src/tint/lang/wgsl/resolver/resolver_helper_test.h"

 #include "gmock/gmock.h"

 using namespace tint::core::number_suffixes;  // NOLINT
 using namespace tint::core::fluent_types;     // NOLINT

 namespace tint::resolver {
 namespace {

 using DualSourceBlendingExtensionTest = ResolverTest;

 // Using the @blend_src attribute without chromium_internal_dual_source_blending enabled should
 // fail.
 TEST_F(DualSourceBlendingExtensionTest, UseBlendSrcAttribWithoutExtensionError) {
     Structure("Output", Vector{
                             Member("a", ty.vec4<f32>(),
                                    Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 0_a)}),
                         });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(
         r()->error(),
         R"(12:34 error: use of '@blend_src' requires enabling extension 'chromium_internal_dual_source_blending')");
 }

 class DualSourceBlendingExtensionTests : public ResolverTest {
   public:
     DualSourceBlendingExtensionTests() {
         Enable(wgsl::Extension::kChromiumInternalDualSourceBlending);
     }
 };

 // Using an F32 as an index value should fail.
 TEST_F(DualSourceBlendingExtensionTests, BlendSrcF32Error) {
     Structure("Output", Vector{
                             Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
                                    Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 0_f)}),
                         });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@blend_srci32' or 'u32' value");
 }

 // Using a floating point number as an index value should fail.
 TEST_F(DualSourceBlendingExtensionTests, BlendSrcFloatValueError) {
     Structure("Output", Vector{
                             Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
                                    Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 1.0_a)}),
                         });
     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@blend_srci32' or 'u32' value");
 }

 // Using a number less than zero as an index value should fail.
 TEST_F(DualSourceBlendingExtensionTests, BlendSrcNegativeValue) {
     Structure("Output", Vector{
                             Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
                                    Vector{Location(0_a), BlendSrc(Source{{12, 34}}, -1_a)}),
                         });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' value must be zero or one");
 }

 // Using a number greater than one as an index value should fail.
 TEST_F(DualSourceBlendingExtensionTests, BlendSrcValueAboveOne) {
     Structure("Output", Vector{
                             Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
                                    Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 2_a)}),
                         });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' value must be zero or one");
 }

 // Using an index value at the same location multiple times should fail.
 TEST_F(DualSourceBlendingExtensionTests, DuplicateBlendSrces) {
     Structure("Output", Vector{
                             Member("a", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(0_a)}),
                             Member(Source{{12, 34}}, "b", ty.vec4<f32>(),
                                    Vector{Location(Source{{12, 34}}, 0_a), BlendSrc(0_a)}),
                         });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@location(0) @blend_src(0)' appears multiple times");
 }

 // Using the index attribute without a location attribute should fail.
 TEST_F(DualSourceBlendingExtensionTests, BlendSrcWithMissingLocationAttribute_Struct) {
     Structure("Output", Vector{
                             Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
                                    Vector{BlendSrc(Source{{12, 34}}, 1_a)}),
                         });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' can only be used with '@location(0)'");
 }

 // Using the index attribute without a location attribute should fail.
 TEST_F(DualSourceBlendingExtensionTests, BlendSrcWithMissingLocationAttribute_ReturnValue) {
     Func("F", Empty, ty.vec4<f32>(),
          Vector{
              Return(Call<vec4<f32>>()),
          },
          Vector{Stage(ast::PipelineStage::kFragment)},
          Vector{
              BlendSrc(Source{{12, 34}}, 1_a),
              Builtin(core::BuiltinValue::kPointSize),
          });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' can only be used with '@location(0)'");
 }

 // Using an index attribute on a struct member should pass.
 TEST_F(DualSourceBlendingExtensionTests, StructMemberBlendSrcAttribute) {
     Structure("Output", Vector{
                             Member("a", ty.vec4<f32>(),
                                    Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 0_a)}),
                         });

     EXPECT_TRUE(r()->Resolve()) << r()->error();
 }

 // Using an index attribute on a global variable should pass. This is needed internally when using
 // @blend_src with the canonicalize_entry_point transform. This test uses an internal attribute to
 // ignore address space, which is how it is used with the canonicalize_entry_point transform.
 TEST_F(DualSourceBlendingExtensionTests, GlobalVariableBlendSrcAttribute) {
     GlobalVar(
         "var", ty.vec4<f32>(),
         Vector{Location(0_a), BlendSrc(0_a), Disable(ast::DisabledValidation::kIgnoreAddressSpace)},
         core::AddressSpace::kOut);

     EXPECT_TRUE(r()->Resolve()) << r()->error();
 }

 // Using the index attribute with a non-zero location should fail.
 TEST_F(DualSourceBlendingExtensionTests, BlendSrcWithNonZeroLocation_Struct) {
     Structure("Output", Vector{
                             Member("a", ty.vec4<f32>(),
                                    Vector{Location(1_a), BlendSrc(Source{{12, 34}}, 0_a)}),
                         });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' can only be used with '@location(0)'");
 }

 // Using the index attribute with a non-zero location should fail.
 TEST_F(DualSourceBlendingExtensionTests, BlendSrcWithNonZeroLocation_ReturnValue) {
     Func("F", Empty, ty.vec4<f32>(),
          Vector{
              Return(Call<vec4<f32>>()),
          },
          Vector{Stage(ast::PipelineStage::kFragment)},
          Vector{
              Location(1_a),
              BlendSrc(Source{{12, 34}}, 1_a),
          });

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' can only be used with '@location(0)'");
 }

 TEST_F(DualSourceBlendingExtensionTests, NoNonZeroCollisionsBetweenInAndOut) {
     // struct NonZeroLocation {
     //   @location(1) a : vec4<f32>,
     // };
     // struct NonZeroBlendSrc {
     //   @location(0) @blend_src(1) a : vec4<f32>,
     // };
     // fn X(in : NonZeroLocation) -> NonZeroBlendSrc { return NonZeroBlendSrc(); }
     // fn Y(in : NonZeroBlendSrc) -> NonZeroLocation { return NonZeroLocation(); }
     Structure("NonZeroLocation", Vector{
                                      Member("a", ty.vec4<f32>(), Vector{Location(1_a)}),
                                  });
     Structure("NonZeroBlendSrc",
               Vector{
                   Member("a", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(1_a)}),
               });
     Func("X", Vector{Param("in", ty("NonZeroLocation"))}, ty("NonZeroBlendSrc"),
          Vector{Return(Call("NonZeroBlendSrc"))}, Vector{Stage(ast::PipelineStage::kFragment)});
     Func("Y", Vector{Param("in", ty("NonZeroBlendSrc"))}, ty("NonZeroLocation"),
          Vector{Return(Call("NonZeroLocation"))}, Vector{Stage(ast::PipelineStage::kFragment)});

     EXPECT_TRUE(r()->Resolve()) << r()->error();
 }

 TEST_F(DualSourceBlendingExtensionTests, MixedBlendSrcAndNonBlendSrcOnLocationZero_Struct) {
     // struct S {
     //   @location(0) a : vec4<f32>,
     //   @location(0) @blend_src(1) b : vec4<f32>,
     // };
     Structure("S", Vector{
                        Member("a", ty.vec4<f32>(),
                               Vector{
                                   Location(Source{{12, 34}}, 0_a),
                               }),
                        Member("b", ty.vec4<f32>(),
                               Vector{Location(0_a), BlendSrc(Source{{56, 78}}, 1_a)}),
                    });

     EXPECT_TRUE(r()->Resolve());
 }

 TEST_F(DualSourceBlendingExtensionTests,
        MixedBlendSrcAndNonBlendSrcOnLocationZero_StructUsedInEntryPoint) {
     // struct S {
     //   @location(0) a : vec4<f32>,
     //   @location(0) @blend_src(1) b : vec4<f32>,
     // };
     // fn F() -> S { return S(); }
     Structure("S", Vector{
                        Member("a", ty.vec4<f32>(),
                               Vector{
                                   Location(Source{{12, 34}}, 0_a),
                               }),
                        Member("b", ty.vec4<f32>(),
                               Vector{Location(0_a), BlendSrc(Source{{56, 78}}, 1_a)}),
                    });
     Func("F", Empty, ty("S"), Vector{Return(Call("S"))},
          Vector{Stage(ast::PipelineStage::kFragment)});

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(
         r()->error(),
         R"(12:34 error: use of '@blend_src' requires all the output '@location' attributes of the entry point to be paired with a '@blend_src' attribute
 56:78 note: use of '@blend_src' here
 note: while analyzing entry point 'F')");
 }

 class DualSourceBlendingExtensionTestWithParams : public ResolverTestWithParam<int> {
   public:
     DualSourceBlendingExtensionTestWithParams() {
         Enable(wgsl::Extension::kChromiumInternalDualSourceBlending);
     }
 };

 // Rendering to multiple render targets while using dual source blending should fail.
 TEST_P(DualSourceBlendingExtensionTestWithParams,
        MultipleRenderTargetsNotAllowed_BlendSrcAndNoBlendSrc) {
     // struct S {
     //   @location(0) @blend_src(0) a : vec4<f32>,
     //   @location(0) @blend_src(1) b : vec4<f32>,
     //   @location(n)           c : vec4<f32>,
     // };
     // fn F() -> S { return S(); }
     Structure("S",
               Vector{
                   Member("a", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(0_a)}),
                   Member("b", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(Source{{1, 2}}, 1_a)}),
                   Member("c", ty.vec4<f32>(), Vector{Location(Source{{3, 4}}, AInt(GetParam()))}),
               });
     Func("F", Empty, ty("S"), Vector{Return(Call("S"))},
          Vector{Stage(ast::PipelineStage::kFragment)});

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(
         r()->error(),
         R"(3:4 error: use of '@blend_src' requires all the output '@location' attributes of the entry point to be paired with a '@blend_src' attribute
 1:2 note: use of '@blend_src' here
 note: while analyzing entry point 'F')");
 }

 TEST_P(DualSourceBlendingExtensionTestWithParams,
        MultipleRenderTargetsNotAllowed_NonZeroLocationThenBlendSrc) {
     // struct S {
     //   @location(n)           a : vec4<f32>,
     //   @location(0) @blend_src(0) b : vec4<f32>,
     //   @location(0) @blend_src(1) c : vec4<f32>,
     // };
     // fn F() -> S { return S(); }
     Structure("S",
               Vector{
                   Member("a", ty.vec4<f32>(), Vector{Location(Source{{1, 2}}, AInt(GetParam()))}),
                   Member("b", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(0_a)}),
                   Member("c", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(Source{{3, 4}}, 1_a)}),
               });
     Func(Source{{5, 6}}, "F", Empty, ty("S"), Vector{Return(Call("S"))},
          Vector{Stage(ast::PipelineStage::kFragment)});

     EXPECT_FALSE(r()->Resolve());
     EXPECT_EQ(
         r()->error(),
         R"(1:2 error: use of '@blend_src' requires all the output '@location' attributes of the entry point to be paired with a '@blend_src' attribute
 note: use of '@blend_src' here
 5:6 note: while analyzing entry point 'F')");
 }

 INSTANTIATE_TEST_SUITE_P(DualSourceBlendingExtensionTests,
                          DualSourceBlendingExtensionTestWithParams,
                          testing::Values(1, 2, 3, 4, 5, 6, 7));

 }  // namespace
 }  // namespace tint::resolver
	// Copyright 2023 The Dawn & Tint Authors
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are met:
	//
	// 1. Redistributions of source code must retain the above copyright notice, this
	// list of conditions and the following disclaimer.
	//
	// 2. Redistributions in binary form must reproduce the above copyright notice,
	// this list of conditions and the following disclaimer in the documentation
	// and/or other materials provided with the distribution.
	//
	// 3. Neither the name of the copyright holder nor the names of its
	// contributors may be used to endorse or promote products derived from
	// this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
	// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
	// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
	// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	#include "src/tint/lang/core/fluent_types.h"
	#include "src/tint/lang/wgsl/resolver/resolver.h"
	#include "src/tint/lang/wgsl/resolver/resolver_helper_test.h"

	#include "gmock/gmock.h"

	using namespace tint::core::number_suffixes; // NOLINT
	using namespace tint::core::fluent_types; // NOLINT

	namespace tint::resolver {
	namespace {

	using DualSourceBlendingExtensionTest = ResolverTest;

	// Using the @blend_src attribute without chromium_internal_dual_source_blending enabled should
	// fail.
	TEST_F(DualSourceBlendingExtensionTest, UseBlendSrcAttribWithoutExtensionError) {
	Structure("Output", Vector{
	Member("a", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 0_a)}),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(
	r()->error(),
	R"(12:34 error: use of '@blend_src' requires enabling extension 'chromium_internal_dual_source_blending')");
	}

	class DualSourceBlendingExtensionTests : public ResolverTest {
	public:
	DualSourceBlendingExtensionTests() {
	Enable(wgsl::Extension::kChromiumInternalDualSourceBlending);
	}
	};

	// Using an F32 as an index value should fail.
	TEST_F(DualSourceBlendingExtensionTests, BlendSrcF32Error) {
	Structure("Output", Vector{
	Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 0_f)}),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@blend_srci32' or 'u32' value");
	}

	// Using a floating point number as an index value should fail.
	TEST_F(DualSourceBlendingExtensionTests, BlendSrcFloatValueError) {
	Structure("Output", Vector{
	Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 1.0_a)}),
	});
	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@blend_srci32' or 'u32' value");
	}

	// Using a number less than zero as an index value should fail.
	TEST_F(DualSourceBlendingExtensionTests, BlendSrcNegativeValue) {
	Structure("Output", Vector{
	Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(Source{{12, 34}}, -1_a)}),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' value must be zero or one");
	}

	// Using a number greater than one as an index value should fail.
	TEST_F(DualSourceBlendingExtensionTests, BlendSrcValueAboveOne) {
	Structure("Output", Vector{
	Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 2_a)}),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' value must be zero or one");
	}

	// Using an index value at the same location multiple times should fail.
	TEST_F(DualSourceBlendingExtensionTests, DuplicateBlendSrces) {
	Structure("Output", Vector{
	Member("a", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(0_a)}),
	Member(Source{{12, 34}}, "b", ty.vec4<f32>(),
	Vector{Location(Source{{12, 34}}, 0_a), BlendSrc(0_a)}),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@location(0) @blend_src(0)' appears multiple times");
	}

	// Using the index attribute without a location attribute should fail.
	TEST_F(DualSourceBlendingExtensionTests, BlendSrcWithMissingLocationAttribute_Struct) {
	Structure("Output", Vector{
	Member(Source{{12, 34}}, "a", ty.vec4<f32>(),
	Vector{BlendSrc(Source{{12, 34}}, 1_a)}),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' can only be used with '@location(0)'");
	}

	// Using the index attribute without a location attribute should fail.
	TEST_F(DualSourceBlendingExtensionTests, BlendSrcWithMissingLocationAttribute_ReturnValue) {
	Func("F", Empty, ty.vec4<f32>(),
	Vector{
	Return(Call<vec4<f32>>()),
	},
	Vector{Stage(ast::PipelineStage::kFragment)},
	Vector{
	BlendSrc(Source{{12, 34}}, 1_a),
	Builtin(core::BuiltinValue::kPointSize),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' can only be used with '@location(0)'");
	}

	// Using an index attribute on a struct member should pass.
	TEST_F(DualSourceBlendingExtensionTests, StructMemberBlendSrcAttribute) {
	Structure("Output", Vector{
	Member("a", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(Source{{12, 34}}, 0_a)}),
	});

	EXPECT_TRUE(r()->Resolve()) << r()->error();
	}

	// Using an index attribute on a global variable should pass. This is needed internally when using
	// @blend_src with the canonicalize_entry_point transform. This test uses an internal attribute to
	// ignore address space, which is how it is used with the canonicalize_entry_point transform.
	TEST_F(DualSourceBlendingExtensionTests, GlobalVariableBlendSrcAttribute) {
	GlobalVar(
	"var", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(0_a), Disable(ast::DisabledValidation::kIgnoreAddressSpace)},
	core::AddressSpace::kOut);

	EXPECT_TRUE(r()->Resolve()) << r()->error();
	}

	// Using the index attribute with a non-zero location should fail.
	TEST_F(DualSourceBlendingExtensionTests, BlendSrcWithNonZeroLocation_Struct) {
	Structure("Output", Vector{
	Member("a", ty.vec4<f32>(),
	Vector{Location(1_a), BlendSrc(Source{{12, 34}}, 0_a)}),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' can only be used with '@location(0)'");
	}

	// Using the index attribute with a non-zero location should fail.
	TEST_F(DualSourceBlendingExtensionTests, BlendSrcWithNonZeroLocation_ReturnValue) {
	Func("F", Empty, ty.vec4<f32>(),
	Vector{
	Return(Call<vec4<f32>>()),
	},
	Vector{Stage(ast::PipelineStage::kFragment)},
	Vector{
	Location(1_a),
	BlendSrc(Source{{12, 34}}, 1_a),
	});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(r()->error(), "12:34 error: '@blend_src' can only be used with '@location(0)'");
	}

	TEST_F(DualSourceBlendingExtensionTests, NoNonZeroCollisionsBetweenInAndOut) {
	// struct NonZeroLocation {
	// @location(1) a : vec4<f32>,
	// };
	// struct NonZeroBlendSrc {
	// @location(0) @blend_src(1) a : vec4<f32>,
	// };
	// fn X(in : NonZeroLocation) -> NonZeroBlendSrc { return NonZeroBlendSrc(); }
	// fn Y(in : NonZeroBlendSrc) -> NonZeroLocation { return NonZeroLocation(); }
	Structure("NonZeroLocation", Vector{
	Member("a", ty.vec4<f32>(), Vector{Location(1_a)}),
	});
	Structure("NonZeroBlendSrc",
	Vector{
	Member("a", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(1_a)}),
	});
	Func("X", Vector{Param("in", ty("NonZeroLocation"))}, ty("NonZeroBlendSrc"),
	Vector{Return(Call("NonZeroBlendSrc"))}, Vector{Stage(ast::PipelineStage::kFragment)});
	Func("Y", Vector{Param("in", ty("NonZeroBlendSrc"))}, ty("NonZeroLocation"),
	Vector{Return(Call("NonZeroLocation"))}, Vector{Stage(ast::PipelineStage::kFragment)});

	EXPECT_TRUE(r()->Resolve()) << r()->error();
	}

	TEST_F(DualSourceBlendingExtensionTests, MixedBlendSrcAndNonBlendSrcOnLocationZero_Struct) {
	// struct S {
	// @location(0) a : vec4<f32>,
	// @location(0) @blend_src(1) b : vec4<f32>,
	// };
	Structure("S", Vector{
	Member("a", ty.vec4<f32>(),
	Vector{
	Location(Source{{12, 34}}, 0_a),
	}),
	Member("b", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(Source{{56, 78}}, 1_a)}),
	});

	EXPECT_TRUE(r()->Resolve());
	}

	TEST_F(DualSourceBlendingExtensionTests,
	MixedBlendSrcAndNonBlendSrcOnLocationZero_StructUsedInEntryPoint) {
	// struct S {
	// @location(0) a : vec4<f32>,
	// @location(0) @blend_src(1) b : vec4<f32>,
	// };
	// fn F() -> S { return S(); }
	Structure("S", Vector{
	Member("a", ty.vec4<f32>(),
	Vector{
	Location(Source{{12, 34}}, 0_a),
	}),
	Member("b", ty.vec4<f32>(),
	Vector{Location(0_a), BlendSrc(Source{{56, 78}}, 1_a)}),
	});
	Func("F", Empty, ty("S"), Vector{Return(Call("S"))},
	Vector{Stage(ast::PipelineStage::kFragment)});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(
	r()->error(),
	R"(12:34 error: use of '@blend_src' requires all the output '@location' attributes of the entry point to be paired with a '@blend_src' attribute
	56:78 note: use of '@blend_src' here
	note: while analyzing entry point 'F')");
	}

	class DualSourceBlendingExtensionTestWithParams : public ResolverTestWithParam<int> {
	public:
	DualSourceBlendingExtensionTestWithParams() {
	Enable(wgsl::Extension::kChromiumInternalDualSourceBlending);
	}
	};

	// Rendering to multiple render targets while using dual source blending should fail.
	TEST_P(DualSourceBlendingExtensionTestWithParams,
	MultipleRenderTargetsNotAllowed_BlendSrcAndNoBlendSrc) {
	// struct S {
	// @location(0) @blend_src(0) a : vec4<f32>,
	// @location(0) @blend_src(1) b : vec4<f32>,
	// @location(n) c : vec4<f32>,
	// };
	// fn F() -> S { return S(); }
	Structure("S",
	Vector{
	Member("a", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(0_a)}),
	Member("b", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(Source{{1, 2}}, 1_a)}),
	Member("c", ty.vec4<f32>(), Vector{Location(Source{{3, 4}}, AInt(GetParam()))}),
	});
	Func("F", Empty, ty("S"), Vector{Return(Call("S"))},
	Vector{Stage(ast::PipelineStage::kFragment)});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(
	r()->error(),
	R"(3:4 error: use of '@blend_src' requires all the output '@location' attributes of the entry point to be paired with a '@blend_src' attribute
	1:2 note: use of '@blend_src' here
	note: while analyzing entry point 'F')");
	}

	TEST_P(DualSourceBlendingExtensionTestWithParams,
	MultipleRenderTargetsNotAllowed_NonZeroLocationThenBlendSrc) {
	// struct S {
	// @location(n) a : vec4<f32>,
	// @location(0) @blend_src(0) b : vec4<f32>,
	// @location(0) @blend_src(1) c : vec4<f32>,
	// };
	// fn F() -> S { return S(); }
	Structure("S",
	Vector{
	Member("a", ty.vec4<f32>(), Vector{Location(Source{{1, 2}}, AInt(GetParam()))}),
	Member("b", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(0_a)}),
	Member("c", ty.vec4<f32>(), Vector{Location(0_a), BlendSrc(Source{{3, 4}}, 1_a)}),
	});
	Func(Source{{5, 6}}, "F", Empty, ty("S"), Vector{Return(Call("S"))},
	Vector{Stage(ast::PipelineStage::kFragment)});

	EXPECT_FALSE(r()->Resolve());
	EXPECT_EQ(
	r()->error(),
	R"(1:2 error: use of '@blend_src' requires all the output '@location' attributes of the entry point to be paired with a '@blend_src' attribute
	note: use of '@blend_src' here
	5:6 note: while analyzing entry point 'F')");
	}

	INSTANTIATE_TEST_SUITE_P(DualSourceBlendingExtensionTests,
	DualSourceBlendingExtensionTestWithParams,
	testing::Values(1, 2, 3, 4, 5, 6, 7));

	} // namespace
	} // namespace tint::resolver