// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "src/ast/discard_statement.h"
#include "src/ast/return_statement.h"
#include "src/ast/stage_decoration.h"
#include "src/resolver/resolver.h"
#include "src/resolver/resolver_test_helper.h"

#include "gmock/gmock.h"

namespace tint {
namespace {

class ResolverFunctionValidationTest : public resolver::TestHelper,
                                       public testing::Test {};

TEST_F(ResolverFunctionValidationTest, FunctionNamesMustBeUnique_fail) {
  // fn func() -> i32 { return 2; }
  // fn func() -> i32 { return 2; }
  Func(Source{{56, 78}}, "func", ast::VariableList{}, ty.i32(),
       ast::StatementList{
           Return(2),
       },
       ast::DecorationList{});

  Func(Source{{12, 34}}, "func", ast::VariableList{}, ty.i32(),
       ast::StatementList{
           Return(2),
       },
       ast::DecorationList{});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            R"(12:34 error: redefinition of 'func'
56:78 note: previous definition is here)");
}

TEST_F(ResolverFunctionValidationTest, ParameterNamesMustBeUnique_fail) {
  // fn func(common_name : f32, x : i32, common_name : u32) { }
  Func("func",
       {
           Param(Source{{56, 78}}, "common_name", ty.f32()),
           Param("x", ty.i32()),
           Param(Source{{12, 34}}, "common_name", ty.u32()),
       },
       ty.void_(), {});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            R"(12:34 error: redefinition of parameter 'common_name'
56:78 note: previous definition is here)");
}

TEST_F(ResolverFunctionValidationTest, ParameterNamesMustBeUnique_pass) {
  // fn func_a(common_name : f32) { }
  // fn func_b(common_name : f32) { }
  Func("func_a", {Param("common_name", ty.f32())}, ty.void_(), {});
  Func("func_b", {Param("common_name", ty.f32())}, ty.void_(), {});

  EXPECT_TRUE(r()->Resolve());
  EXPECT_EQ(r()->error(), "");
}

TEST_F(ResolverFunctionValidationTest,
       ParameterNamesMustBeUniqueShadowsGlobal_pass) {
  // var<private> common_name : f32;
  // fn func(common_name : f32) { }
  Global("common_name", ty.f32(), ast::StorageClass::kPrivate);
  Func("func", {Param("common_name", ty.f32())}, ty.void_(), {});

  EXPECT_TRUE(r()->Resolve());
  EXPECT_EQ(r()->error(), "");
}

TEST_F(ResolverFunctionValidationTest,
       VoidFunctionEndWithoutReturnStatement_Pass) {
  // fn func { var a:i32 = 2; }
  auto* var = Var("a", ty.i32(), ast::StorageClass::kNone, Expr(2));

  Func(Source{Source::Location{12, 34}}, "func", ast::VariableList{},
       ty.void_(),
       ast::StatementList{
           Decl(var),
       });

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

TEST_F(ResolverFunctionValidationTest,
       FunctionNameSameAsGlobalVariableName_Fail) {
  // var foo:f32 = 3.14;
  // fn foo() -> void {}

  auto* global_var = Var(Source{Source::Location{56, 78}}, "foo", ty.f32(),
                         ast::StorageClass::kPrivate, Expr(3.14f));
  AST().AddGlobalVariable(global_var);

  Func(Source{Source::Location{12, 34}}, "foo", ast::VariableList{}, ty.void_(),
       ast::StatementList{}, ast::DecorationList{});

  EXPECT_FALSE(r()->Resolve()) << r()->error();
  EXPECT_EQ(r()->error(),
            "12:34 error: redefinition of 'foo'\n56:78 note: previous "
            "definition is here");
}

TEST_F(ResolverFunctionValidationTest,
       GlobalVariableNameSameAFunctionName_Fail) {
  // fn foo() -> void {}
  // var<private> foo:f32 = 3.14;

  Func(Source{Source::Location{12, 34}}, "foo", ast::VariableList{}, ty.void_(),
       ast::StatementList{}, ast::DecorationList{});
  auto* global_var = Var(Source{Source::Location{56, 78}}, "foo", ty.f32(),
                         ast::StorageClass::kPrivate, Expr(3.14f));
  AST().AddGlobalVariable(global_var);

  EXPECT_FALSE(r()->Resolve()) << r()->error();
  EXPECT_EQ(r()->error(),
            "56:78 error: redefinition of 'foo'\n12:34 note: previous "
            "definition is here");
}

TEST_F(ResolverFunctionValidationTest, FunctionUsingSameVariableName_Pass) {
  // fn func() -> i32 {
  //   var func:i32 = 0;
  //   return func;
  // }

  auto* var = Var("func", ty.i32(), ast::StorageClass::kNone, Expr(0));
  Func("func", ast::VariableList{}, ty.i32(),
       ast::StatementList{
           Decl(var),
           Return(Source{Source::Location{12, 34}}, Expr("func")),
       },
       ast::DecorationList{});

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

TEST_F(ResolverFunctionValidationTest,
       FunctionNameSameAsFunctionScopeVariableName_Pass) {
  // fn a() -> void { var b:i32 = 0; }
  // fn b() -> i32 { return 2; }

  auto* var = Var("b", ty.i32(), ast::StorageClass::kNone, Expr(0));
  Func("a", ast::VariableList{}, ty.void_(),
       ast::StatementList{
           Decl(var),
       },
       ast::DecorationList{});

  Func(Source{Source::Location{12, 34}}, "b", ast::VariableList{}, ty.i32(),
       ast::StatementList{
           Return(2),
       },
       ast::DecorationList{});

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

TEST_F(ResolverFunctionValidationTest, UnreachableCode_return) {
  // fn func() -> {
  //  var a : i32;
  //  return;
  //  a = 2;
  //}

  Func("func", ast::VariableList{}, ty.void_(),
       {
           Decl(Var("a", ty.i32(), ast::StorageClass::kNone, Expr(2))),
           Return(),
           Assign(Source{{12, 34}}, "a", 2),
       });
  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(), "12:34 error: code is unreachable");
}

TEST_F(ResolverFunctionValidationTest, UnreachableCode_return_InBlocks) {
  // fn func() -> {
  //  var a : i32;
  //  {{{return;}}}
  //  a = 2;
  //}

  Func("func", ast::VariableList{}, ty.void_(),
       {
           Decl(Var("a", ty.i32(), ast::StorageClass::kNone, Expr(2))),
           Block(Block(Block(Return()))),
           Assign(Source{{12, 34}}, "a", 2),
       });
  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(), "12:34 error: code is unreachable");
}

TEST_F(ResolverFunctionValidationTest, UnreachableCode_discard) {
  // fn func() -> {
  //  var a : i32;
  //  discard;
  //  a = 2;
  //}

  Func("func", ast::VariableList{}, ty.void_(),
       {
           Decl(Var("a", ty.i32(), ast::StorageClass::kNone, Expr(2))),
           create<ast::DiscardStatement>(),
           Assign(Source{{12, 34}}, "a", 2),
       });
  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(), "12:34 error: code is unreachable");
}

TEST_F(ResolverFunctionValidationTest, UnreachableCode_discard_InBlocks) {
  // fn func() -> {
  //  var a : i32;
  //  {{{discard;}}}
  //  a = 2;
  //}

  Func("func", ast::VariableList{}, ty.void_(),
       {
           Decl(Var("a", ty.i32(), ast::StorageClass::kNone, Expr(2))),
           Block(Block(Block(create<ast::DiscardStatement>()))),
           Assign(Source{{12, 34}}, "a", 2),
       });
  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(), "12:34 error: code is unreachable");
}

TEST_F(ResolverFunctionValidationTest, FunctionEndWithoutReturnStatement_Fail) {
  // fn func() -> int { var a:i32 = 2; }

  auto* var = Var("a", ty.i32(), ast::StorageClass::kNone, Expr(2));

  Func(Source{Source::Location{12, 34}}, "func", ast::VariableList{}, ty.i32(),
       ast::StatementList{
           Decl(var),
       },
       ast::DecorationList{});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: non-void function must end with a return statement");
}

TEST_F(ResolverFunctionValidationTest,
       VoidFunctionEndWithoutReturnStatementEmptyBody_Pass) {
  // fn func {}

  Func(Source{Source::Location{12, 34}}, "func", ast::VariableList{},
       ty.void_(), ast::StatementList{});

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

TEST_F(ResolverFunctionValidationTest,
       FunctionEndWithoutReturnStatementEmptyBody_Fail) {
  // fn func() -> int {}

  Func(Source{Source::Location{12, 34}}, "func", ast::VariableList{}, ty.i32(),
       ast::StatementList{}, ast::DecorationList{});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: non-void function must end with a return statement");
}

TEST_F(ResolverFunctionValidationTest,
       FunctionTypeMustMatchReturnStatementType_Pass) {
  // fn func { return; }

  Func("func", ast::VariableList{}, ty.void_(),
       ast::StatementList{
           Return(),
       });

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

TEST_F(ResolverFunctionValidationTest,
       FunctionTypeMustMatchReturnStatementType_fail) {
  // fn func { return 2; }
  Func("func", ast::VariableList{}, ty.void_(),
       ast::StatementList{
           Return(Source{Source::Location{12, 34}}, Expr(2)),
       },
       ast::DecorationList{});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: return statement type must match its function return "
            "type, returned 'i32', expected 'void'");
}

TEST_F(ResolverFunctionValidationTest,
       FunctionTypeMustMatchReturnStatementType_void_fail) {
  // fn v { return; }
  // fn func { return v(); }
  Func("v", {}, ty.void_(), {Return()});
  Func("func", {}, ty.void_(),
       {
           Return(Call(Source{Source::Location{12, 34}}, "v")),
       });

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(), "12:34 error: function 'v' does not return a value");
}

TEST_F(ResolverFunctionValidationTest,
       FunctionTypeMustMatchReturnStatementTypeMissing_fail) {
  // fn func() -> f32 { return; }
  Func("func", ast::VariableList{}, ty.f32(),
       ast::StatementList{
           Return(Source{Source::Location{12, 34}}, nullptr),
       },
       ast::DecorationList{});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: return statement type must match its function return "
            "type, returned 'void', expected 'f32'");
}

TEST_F(ResolverFunctionValidationTest,
       FunctionTypeMustMatchReturnStatementTypeF32_pass) {
  // fn func() -> f32 { return 2.0; }
  Func("func", ast::VariableList{}, ty.f32(),
       ast::StatementList{
           Return(Source{Source::Location{12, 34}}, Expr(2.f)),
       },
       ast::DecorationList{});

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

TEST_F(ResolverFunctionValidationTest,
       FunctionTypeMustMatchReturnStatementTypeF32_fail) {
  // fn func() -> f32 { return 2; }
  Func("func", ast::VariableList{}, ty.f32(),
       ast::StatementList{
           Return(Source{Source::Location{12, 34}}, Expr(2)),
       },
       ast::DecorationList{});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: return statement type must match its function return "
            "type, returned 'i32', expected 'f32'");
}

TEST_F(ResolverFunctionValidationTest,
       FunctionTypeMustMatchReturnStatementTypeF32Alias_pass) {
  // type myf32 = f32;
  // fn func() -> myf32 { return 2.0; }
  auto* myf32 = Alias("myf32", ty.f32());
  Func("func", ast::VariableList{}, ty.Of(myf32),
       ast::StatementList{
           Return(Source{Source::Location{12, 34}}, Expr(2.f)),
       },
       ast::DecorationList{});

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

TEST_F(ResolverFunctionValidationTest,
       FunctionTypeMustMatchReturnStatementTypeF32Alias_fail) {
  // type myf32 = f32;
  // fn func() -> myf32 { return 2; }
  auto* myf32 = Alias("myf32", ty.f32());
  Func("func", ast::VariableList{}, ty.Of(myf32),
       ast::StatementList{
           Return(Source{Source::Location{12, 34}}, Expr(2u)),
       },
       ast::DecorationList{});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: return statement type must match its function return "
            "type, returned 'u32', expected 'f32'");
}

TEST_F(ResolverFunctionValidationTest, CannotCallEntryPoint) {
  // [[stage(compute), workgroup_size(1)]] fn entrypoint() {}
  // fn func() { return entrypoint(); }
  Func("entrypoint", ast::VariableList{}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute), WorkgroupSize(1)});

  Func("func", ast::VariableList{}, ty.void_(),
       {
           CallStmt(Call(Source{{12, 34}}, "entrypoint")),
       });

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(
      r()->error(),

      R"(12:34 error: entry point functions cannot be the target of a function call)");
}

TEST_F(ResolverFunctionValidationTest, PipelineStage_MustBeUnique_Fail) {
  // [[stage(fragment)]]
  // [[stage(vertex)]]
  // fn main() { return; }
  Func(Source{Source::Location{12, 34}}, "main", ast::VariableList{},
       ty.void_(),
       ast::StatementList{
           Return(),
       },
       ast::DecorationList{
           Stage(Source{{12, 34}}, ast::PipelineStage::kVertex),
           Stage(Source{{56, 78}}, ast::PipelineStage::kFragment),
       });

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            R"(56:78 error: duplicate stage decoration
12:34 note: first decoration declared here)");
}

TEST_F(ResolverFunctionValidationTest, NoPipelineEntryPoints) {
  Func("vtx_func", ast::VariableList{}, ty.void_(),
       ast::StatementList{
           Return(),
       },
       ast::DecorationList{});

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

TEST_F(ResolverFunctionValidationTest, FunctionVarInitWithParam) {
  // fn foo(bar : f32){
  //   var baz : f32 = bar;
  // }

  auto* bar = Param("bar", ty.f32());
  auto* baz = Var("baz", ty.f32(), ast::StorageClass::kNone, Expr("bar"));

  Func("foo", ast::VariableList{bar}, ty.void_(), ast::StatementList{Decl(baz)},
       ast::DecorationList{});

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

TEST_F(ResolverFunctionValidationTest, FunctionConstInitWithParam) {
  // fn foo(bar : f32){
  //   let baz : f32 = bar;
  // }

  auto* bar = Param("bar", ty.f32());
  auto* baz = Const("baz", ty.f32(), Expr("bar"));

  Func("foo", ast::VariableList{bar}, ty.void_(), ast::StatementList{Decl(baz)},
       ast::DecorationList{});

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

TEST_F(ResolverFunctionValidationTest, FunctionParamsConst) {
  Func("foo", {Param(Sym("arg"), ty.i32())}, ty.void_(),
       {Assign(Expr(Source{{12, 34}}, "arg"), Expr(1)), Return()});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: cannot assign to function parameter\nnote: 'arg' is "
            "declared here:");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_GoodType_ConstU32) {
  // let x = 4u;
  // let x = 8u;
  // [[stage(compute), workgroup_size(x, y, 16u]
  // fn main() {}
  GlobalConst("x", ty.u32(), Expr(4u));
  GlobalConst("y", ty.u32(), Expr(8u));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr("x"), Expr("y"), Expr(16u))});

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

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_GoodType_U32) {
  // [[stage(compute), workgroup_size(1u, 2u, 3u)]
  // fn main() {}

  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Source{{12, 34}}, Expr(1u), Expr(2u), Expr(3u))});

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

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_MismatchTypeU32) {
  // [[stage(compute), workgroup_size(1u, 2u, 3)]
  // fn main() {}

  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr(1u), Expr(2u), Expr(Source{{12, 34}}, 3))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size arguments must be of the same type, "
            "either i32 or u32");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_MismatchTypeI32) {
  // [[stage(compute), workgroup_size(1, 2u, 3)]
  // fn main() {}

  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr(1), Expr(Source{{12, 34}}, 2u), Expr(3))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size arguments must be of the same type, "
            "either i32 or u32");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Const_TypeMismatch) {
  // let x = 64u;
  // [[stage(compute), workgroup_size(1, x)]
  // fn main() {}
  GlobalConst("x", ty.u32(), Expr(64u));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr(1), Expr(Source{Source::Location{12, 34}}, "x"))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size arguments must be of the same type, "
            "either i32 or u32");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Const_TypeMismatch2) {
  // let x = 64u;
  // let y = 32;
  // [[stage(compute), workgroup_size(x, y)]
  // fn main() {}
  GlobalConst("x", ty.u32(), Expr(64u));
  GlobalConst("y", ty.i32(), Expr(32));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr("x"), Expr(Source{Source::Location{12, 34}}, "y"))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size arguments must be of the same type, "
            "either i32 or u32");
}
TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Mismatch_ConstU32) {
  // let x = 4u;
  // let x = 8u;
  // [[stage(compute), workgroup_size(x, y, 16]
  // fn main() {}
  GlobalConst("x", ty.u32(), Expr(4u));
  GlobalConst("y", ty.u32(), Expr(8u));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr("x"), Expr("y"),
                      Expr(Source{Source::Location{12, 34}}, 16))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size arguments must be of the same type, "
            "either i32 or u32");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Literal_BadType) {
  // [[stage(compute), workgroup_size(64.0)]
  // fn main() {}

  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(create<ast::ScalarConstructorExpression>(
            Source{Source::Location{12, 34}}, Literal(64.f)))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be either literal or "
            "module-scope constant of type i32 or u32");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Literal_Negative) {
  // [[stage(compute), workgroup_size(-2)]
  // fn main() {}

  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(create<ast::ScalarConstructorExpression>(
            Source{Source::Location{12, 34}}, Literal(-2)))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be at least 1");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Literal_Zero) {
  // [[stage(compute), workgroup_size(0)]
  // fn main() {}

  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(create<ast::ScalarConstructorExpression>(
            Source{Source::Location{12, 34}}, Literal(0)))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be at least 1");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Const_BadType) {
  // let x = 64.0;
  // [[stage(compute), workgroup_size(x)]
  // fn main() {}
  GlobalConst("x", ty.f32(), Expr(64.f));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr(Source{Source::Location{12, 34}}, "x"))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be either literal or "
            "module-scope constant of type i32 or u32");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Const_Negative) {
  // let x = -2;
  // [[stage(compute), workgroup_size(x)]
  // fn main() {}
  GlobalConst("x", ty.i32(), Expr(-2));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr(Source{Source::Location{12, 34}}, "x"))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be at least 1");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_Const_Zero) {
  // let x = 0;
  // [[stage(compute), workgroup_size(x)]
  // fn main() {}
  GlobalConst("x", ty.i32(), Expr(0));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr(Source{Source::Location{12, 34}}, "x"))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be at least 1");
}

TEST_F(ResolverFunctionValidationTest,
       WorkgroupSize_Const_NestedZeroValueConstructor) {
  // let x = i32(i32(i32()));
  // [[stage(compute), workgroup_size(x)]
  // fn main() {}
  GlobalConst("x", ty.i32(),
              Construct(ty.i32(), Construct(ty.i32(), Construct(ty.i32()))));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr(Source{Source::Location{12, 34}}, "x"))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be at least 1");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_NonConst) {
  // var<private> x = 0;
  // [[stage(compute), workgroup_size(x)]
  // fn main() {}
  Global("x", ty.i32(), ast::StorageClass::kPrivate, Expr(64));
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(Expr(Source{Source::Location{12, 34}}, "x"))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be either literal or "
            "module-scope constant of type i32 or u32");
}

TEST_F(ResolverFunctionValidationTest, WorkgroupSize_InvalidExpr) {
  // [[stage(compute), workgroup_size(i32(1))]
  // fn main() {}
  Func("main", {}, ty.void_(), {},
       {Stage(ast::PipelineStage::kCompute),
        WorkgroupSize(
            Construct(Source{Source::Location{12, 34}}, ty.i32(), 1))});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: workgroup_size argument must be either a literal or "
            "a module-scope constant");
}

TEST_F(ResolverFunctionValidationTest, ReturnIsConstructible_NonPlain) {
  auto* ret_type =
      ty.pointer(Source{{12, 34}}, ty.i32(), ast::StorageClass::kFunction);
  Func("f", {}, ret_type, {});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: function return type must be a constructible type");
}

TEST_F(ResolverFunctionValidationTest, ReturnIsConstructible_AtomicInt) {
  auto* ret_type = ty.atomic(Source{{12, 34}}, ty.i32());
  Func("f", {}, ret_type, {});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: function return type must be a constructible type");
}

TEST_F(ResolverFunctionValidationTest, ReturnIsConstructible_ArrayOfAtomic) {
  auto* ret_type = ty.array(Source{{12, 34}}, ty.atomic(ty.i32()), 10);
  Func("f", {}, ret_type, {});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: function return type must be a constructible type");
}

TEST_F(ResolverFunctionValidationTest, ReturnIsConstructible_StructOfAtomic) {
  Structure("S", {Member("m", ty.atomic(ty.i32()))});
  auto* ret_type = ty.type_name(Source{{12, 34}}, "S");
  Func("f", {}, ret_type, {});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: function return type must be a constructible type");
}

TEST_F(ResolverFunctionValidationTest, ReturnIsConstructible_RuntimeArray) {
  auto* ret_type = ty.array(Source{{12, 34}}, ty.i32());
  Func("f", {}, ret_type, {});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: function return type must be a constructible type");
}

TEST_F(ResolverFunctionValidationTest, ParameterStoreType_NonAtomicFree) {
  Structure("S", {Member("m", ty.atomic(ty.i32()))});
  auto* ret_type = ty.type_name(Source{{12, 34}}, "S");
  auto* bar = Param(Source{{12, 34}}, "bar", ret_type);
  Func("f", ast::VariableList{bar}, ty.void_(), {});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: store type of function parameter must be a "
            "constructible type");
}

TEST_F(ResolverFunctionValidationTest, ParameterSotreType_AtomicFree) {
  Structure("S", {Member("m", ty.i32())});
  auto* ret_type = ty.type_name(Source{{12, 34}}, "S");
  auto* bar = Param(Source{{12, 34}}, "bar", ret_type);
  Func("f", ast::VariableList{bar}, ty.void_(), {});

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

TEST_F(ResolverFunctionValidationTest, ParametersAtLimit) {
  ast::VariableList params;
  for (int i = 0; i < 255; i++) {
    params.emplace_back(Param("param_" + std::to_string(i), ty.i32()));
  }
  Func(Source{{12, 34}}, "f", params, ty.void_(), {});

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

TEST_F(ResolverFunctionValidationTest, ParametersOverLimit) {
  ast::VariableList params;
  for (int i = 0; i < 256; i++) {
    params.emplace_back(Param("param_" + std::to_string(i), ty.i32()));
  }
  Func(Source{{12, 34}}, "f", params, ty.void_(), {});

  EXPECT_FALSE(r()->Resolve());
  EXPECT_EQ(r()->error(),
            "12:34 error: functions may declare at most 255 parameters");
}

struct TestParams {
  ast::StorageClass storage_class;
  bool should_pass;
};

struct TestWithParams : resolver::ResolverTestWithParam<TestParams> {};

using ResolverFunctionParameterValidationTest = TestWithParams;
TEST_P(ResolverFunctionParameterValidationTest, StorageClass) {
  auto& param = GetParam();
  auto* ptr_type = ty.pointer(Source{{12, 34}}, ty.i32(), param.storage_class);
  auto* arg = Param(Source{{12, 34}}, "p", ptr_type);
  Func("f", ast::VariableList{arg}, ty.void_(), {});

  if (param.should_pass) {
    EXPECT_TRUE(r()->Resolve()) << r()->error();
  } else {
    std::stringstream ss;
    ss << param.storage_class;
    EXPECT_FALSE(r()->Resolve());
    EXPECT_EQ(r()->error(),
              "12:34 error: function parameter of pointer type cannot be in '" +
                  ss.str() + "' storage class");
  }
}
INSTANTIATE_TEST_SUITE_P(
    ResolverTest,
    ResolverFunctionParameterValidationTest,
    testing::Values(TestParams{ast::StorageClass::kNone, false},
                    TestParams{ast::StorageClass::kInput, false},
                    TestParams{ast::StorageClass::kOutput, false},
                    TestParams{ast::StorageClass::kUniform, false},
                    TestParams{ast::StorageClass::kWorkgroup, true},
                    TestParams{ast::StorageClass::kUniformConstant, false},
                    TestParams{ast::StorageClass::kStorage, false},
                    TestParams{ast::StorageClass::kImage, false},
                    TestParams{ast::StorageClass::kPrivate, true},
                    TestParams{ast::StorageClass::kFunction, true}));

}  // namespace
}  // namespace tint