[main] Revert "Map component start tags to C#, for better GTD, FAR, Hover, etc. (#12287) (#12486)

Backport of #12485 to main

/cc @davidwengier

## Customer Impact

## Regression

- [ ] Yes
- [ ] No

[If yes, specify when the regression was introduced. Provide the PR or
commit if known.]

## Testing

[How was the fix verified? How was the issue missed previously? What
tests were added?]

## Risk

[High/Medium/Low. Justify the indication by mentioning how risks were
measured and addressed.]

Author: davidwengier

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs

@@ -2242,9 +2242,9 @@ public class MyComponent : ComponentBase
         AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
         AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
         CompileToAssembly(generated, designTime ? [] : [
-                    // (29,55): error CS0120: An object reference is required for the non-static field, method, or property 'MyComponent.Value'
+                    // (21,55): error CS0120: An object reference is required for the non-static field, method, or property 'MyComponent.Value'
                     //             __builder.AddComponentParameter(1, nameof(global::Test.MyComponent.
-                    Diagnostic(ErrorCode.ERR_ObjectRequired, "global::Test.MyComponent.\r\n#nullable restore\r\n#line (1,14)-(1,19) \"x:\\dir\\subdir\\Test\\TestComponent.cshtml\"\r\nValue").WithArguments("Test.MyComponent.Value").WithLocation(29, 55)
+                    Diagnostic(ErrorCode.ERR_ObjectRequired, "global::Test.MyComponent.\r\n#nullable restore\r\n#line (1,14)-(1,19) \"x:\\dir\\subdir\\Test\\TestComponent.cshtml\"\r\nValue").WithArguments("Test.MyComponent.Value").WithLocation(21, 55)
             ]);
     }
 
@@ -2462,12 +2462,12 @@ public class MyComponent : ComponentBase
         AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
         AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
         CompileToAssembly(generated, designTime ? [] : [
-                // (29,55): error CS0120: An object reference is required for the non-static field, method, or property 'MyComponent.Value'
+                // (21,55): error CS0120: An object reference is required for the non-static field, method, or property 'MyComponent.Value'
                 //             __builder.AddComponentParameter(1, nameof(global::Test.MyComponent.
-                Diagnostic(ErrorCode.ERR_ObjectRequired, "global::Test.MyComponent.\r\n#nullable restore\r\n#line (1,20)-(1,25) \"x:\\dir\\subdir\\Test\\TestComponent.cshtml\"\r\nValue").WithArguments("Test.MyComponent.Value").WithLocation(29, 55),
-                // (46,55): error CS0120: An object reference is required for the non-static field, method, or property 'MyComponent.ValueChanged'
+                Diagnostic(ErrorCode.ERR_ObjectRequired, "global::Test.MyComponent.\r\n#nullable restore\r\n#line (1,20)-(1,25) \"x:\\dir\\subdir\\Test\\TestComponent.cshtml\"\r\nValue").WithArguments("Test.MyComponent.Value").WithLocation(21, 55),
+                // (38,55): error CS0120: An object reference is required for the non-static field, method, or property 'MyComponent.ValueChanged'
                 //             __builder.AddComponentParameter(2, nameof(global::Test.MyComponent.ValueChanged), (global::System.Action<System.Int32>)(__value => ParentValue = __value));
-                Diagnostic(ErrorCode.ERR_ObjectRequired, "global::Test.MyComponent.ValueChanged").WithArguments("Test.MyComponent.ValueChanged").WithLocation(46, 55)
+                Diagnostic(ErrorCode.ERR_ObjectRequired, "global::Test.MyComponent.ValueChanged").WithArguments("Test.MyComponent.ValueChanged").WithLocation(38, 55)
             ]);
     }
 
@@ -2625,9 +2625,9 @@ public class MyComponent : ComponentBase
             : [// x:\dir\subdir\Test\TestComponent.cshtml(1,27): error CS1503: Argument 1: cannot convert from 'string' to 'int'
                // ParentValue
                Diagnostic(ErrorCode.ERR_BadArgType, "ParentValue").WithArguments("1", "string", "int").WithLocation(1, 27),
-               // (46,166): error CS0029: Cannot implicitly convert type 'int' to 'string'
+               // (38,166): error CS0029: Cannot implicitly convert type 'int' to 'string'
                //             __builder.AddComponentParameter(2, nameof(global::Test.MyComponent.ValueChanged), (global::System.Action<global::System.Int32>)(__value => ParentValue = __value));
-               Diagnostic(ErrorCode.ERR_NoImplicitConv, "__value").WithArguments("int", "string").WithLocation(46, 166)]);
+               Diagnostic(ErrorCode.ERR_NoImplicitConv, "__value").WithArguments("int", "string").WithLocation(38, 166)]);
     }
 
     [IntegrationTestFact]
@@ -2704,9 +2704,9 @@ public class MyComponent : ComponentBase
             : [// x:\dir\subdir\Test\TestComponent.cshtml(1,27): error CS1503: Argument 1: cannot convert from 'string' to 'int'
                //                           ParentValue
                Diagnostic(ErrorCode.ERR_BadArgType, "ParentValue").WithArguments("1", "string", "int").WithLocation(1, 27),
-               // (46,351): error CS1503: Argument 2: cannot convert from 'Microsoft.AspNetCore.Components.EventCallback<string>' to 'Microsoft.AspNetCore.Components.EventCallback'
+               // (38,351): error CS1503: Argument 2: cannot convert from 'Microsoft.AspNetCore.Components.EventCallback<string>' to 'Microsoft.AspNetCore.Components.EventCallback'
                //             global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.CreateInferredEventCallback(this, __value => ParentValue = __value, ParentValue)));
-               Diagnostic(ErrorCode.ERR_BadArgType, "global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.CreateInferredEventCallback(this, __value => ParentValue = __value, ParentValue)").WithArguments("2", "Microsoft.AspNetCore.Components.EventCallback<string>", "Microsoft.AspNetCore.Components.EventCallback").WithLocation(46, 351)
+               Diagnostic(ErrorCode.ERR_BadArgType, "global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.CreateInferredEventCallback(this, __value => ParentValue = __value, ParentValue)").WithArguments("2", "Microsoft.AspNetCore.Components.EventCallback<string>", "Microsoft.AspNetCore.Components.EventCallback").WithLocation(38, 351)
             ]
         );
     }
@@ -2911,12 +2911,12 @@ public class MyComponent : ComponentBase
                // (38,195): error CS1662: Cannot convert lambda expression to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type
                //             __o = global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.Linq.Expressions.Expression<global::System.Func<global::System.String>>>(() => ParentValue);
                Diagnostic(ErrorCode.ERR_CantConvAnonMethReturns, "ParentValue").WithArguments("lambda expression").WithLocation(38, 195)]
-            : [// (47,274): error CS0029: Cannot implicitly convert type 'int' to 'string'
+            : [// (39,274): error CS0029: Cannot implicitly convert type 'int' to 'string'
                //             __builder.AddComponentParameter(3, nameof(global::Test.MyComponent.ValueExpression), global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.Linq.Expressions.Expression<global::System.Func<global::System.String>>>(() => ParentValue));
-               Diagnostic(ErrorCode.ERR_NoImplicitConv, "ParentValue").WithArguments("int", "string").WithLocation(47, 274),
-               // (47,274): error CS1662: Cannot convert lambda expression to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type
+               Diagnostic(ErrorCode.ERR_NoImplicitConv, "ParentValue").WithArguments("int", "string").WithLocation(39, 274),
+               // (39,274): error CS1662: Cannot convert lambda expression to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type
                //             __builder.AddComponentParameter(3, nameof(global::Test.MyComponent.ValueExpression), global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.Linq.Expressions.Expression<global::System.Func<global::System.String>>>(() => ParentValue));
-               Diagnostic(ErrorCode.ERR_CantConvAnonMethReturns, "ParentValue").WithArguments("lambda expression").WithLocation(47, 274)
+               Diagnostic(ErrorCode.ERR_CantConvAnonMethReturns, "ParentValue").WithArguments("lambda expression").WithLocation(39, 274)
             ]);
     }
 
@@ -10909,7 +10909,7 @@ public class Counter : ComponentBase
         // Assert
         CompileToAssembly(generated);
         Assert.DoesNotContain("<Counter", generated.Code);
-        Assert.Contains("global::MyComponents.", generated.Code);
+        Assert.Contains("global::MyComponents.Counter", generated.Code);
     }
 
     [IntegrationTestFact]
@@ -11811,9 +11811,9 @@ public class MyComponent : ComponentBase
             : [// x:\dir\subdir\Test\TestComponent.cshtml(1,32): error CS1003: Syntax error, ',' expected
               //                               x
               Diagnostic(ErrorCode.ERR_SyntaxError, "").WithArguments(",").WithLocation(1, 32),
-              // (37,88): error CS1501: No overload for method 'TypeCheck' takes 2 arguments
+              // (29,88): error CS1501: No overload for method 'TypeCheck' takes 2 arguments
               //             __o = global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.String>(
-              Diagnostic(ErrorCode.ERR_BadArgCount, "TypeCheck<global::System.String>").WithArguments("TypeCheck", "2").WithLocation(37, 88)]
+              Diagnostic(ErrorCode.ERR_BadArgCount, "TypeCheck<global::System.String>").WithArguments("TypeCheck", "2").WithLocation(29, 88)]
             );
         Assert.NotEmpty(generated.RazorDiagnostics);
     }

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitBooleanConversion/TestComponent.codegen.cs

@@ -54,15 +54,7 @@ internal static class TypeInference
     {
         public static void CreateMyComponent_0<T>(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder, int seq, int __seq0, global::Test.MyClass<T> __arg0, int __seq1, global::System.Boolean __arg1)
         {
-        __builder.OpenComponent<global::Test.
-#nullable restore
-#line (1,2)-(1,13) "x:\dir\subdir\Test\TestComponent.cshtml"
-MyComponent
-
-#line default
-#line hidden
-#nullable disable
-        <T>>(seq);
+        __builder.OpenComponent<global::Test.MyComponent<T>>(seq);
         __builder.AddAttribute(__seq0, nameof(global::Test.MyComponent<T>.
 #nullable restore
 #line (1,14)-(1,25) "x:\dir\subdir\Test\TestComponent.cshtml"

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitBooleanConversion/TestComponent.mappings.txt

@@ -17,18 +17,13 @@ Generated Location: (1189:40,0 [42] )
     private MyClass<string> c = new();
 |
 
-Source Location: (1:0,1 [11] x:\dir\subdir\Test\TestComponent.cshtml)
-|MyComponent|
-Generated Location: (1766:59,0 [11] )
-|MyComponent|
-
 Source Location: (13:0,13 [11] x:\dir\subdir\Test\TestComponent.cshtml)
 |MyParameter|
-Generated Location: (2007:68,0 [11] )
+Generated Location: (1864:60,0 [11] )
 |MyParameter|
 
 Source Location: (29:0,29 [13] x:\dir\subdir\Test\TestComponent.cshtml)
 |BoolParameter|
-Generated Location: (2257:77,0 [13] )
+Generated Location: (2114:69,0 [13] )
 |BoolParameter|
 

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitStringConversion_Bind/TestComponent.codegen.cs

@@ -70,15 +70,7 @@ internal static class TypeInference
     {
         public static void CreateMyComponent_0<T>(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder, int seq, int __seq0, global::System.Boolean __arg0, int __seq1, global::System.String __arg1, int __seq2, global::System.Delegate __arg2, int __seq3, global::System.Object __arg3, int __seq4, global::Test.MyClass<T> __arg4, int __seq5, global::Microsoft.AspNetCore.Components.EventCallback<global::Test.MyClass<T>> __arg5)
         {
-        __builder.OpenComponent<global::Test.
-#nullable restore
-#line (1,2)-(1,13) "x:\dir\subdir\Test\TestComponent.cshtml"
-MyComponent
-
-#line default
-#line hidden
-#nullable disable
-        <T>>(seq);
+        __builder.OpenComponent<global::Test.MyComponent<T>>(seq);
         __builder.AddAttribute(__seq0, nameof(global::Test.MyComponent<T>.
 #nullable restore
 #line (2,5)-(2,18) "x:\dir\subdir\Test\TestComponent.cshtml"

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitStringConversion_Bind/TestComponent.mappings.txt

@@ -27,33 +27,28 @@ Generated Location: (1731:56,0 [42] )
     private MyClass<string> c = new();
 |
 
-Source Location: (1:0,1 [11] x:\dir\subdir\Test\TestComponent.cshtml)
-|MyComponent|
-Generated Location: (2535:75,0 [11] )
-|MyComponent|
-
 Source Location: (40:1,4 [13] x:\dir\subdir\Test\TestComponent.cshtml)
 |BoolParameter|
-Generated Location: (2775:84,0 [13] )
+Generated Location: (2632:76,0 [13] )
 |BoolParameter|
 
 Source Location: (66:2,4 [15] x:\dir\subdir\Test\TestComponent.cshtml)
 |StringParameter|
-Generated Location: (3026:93,0 [15] )
+Generated Location: (2883:85,0 [15] )
 |StringParameter|
 
 Source Location: (93:3,4 [17] x:\dir\subdir\Test\TestComponent.cshtml)
 |DelegateParameter|
-Generated Location: (3279:102,0 [17] )
+Generated Location: (3136:94,0 [17] )
 |DelegateParameter|
 
 Source Location: (128:4,4 [15] x:\dir\subdir\Test\TestComponent.cshtml)
 |ObjectParameter|
-Generated Location: (3534:111,0 [15] )
+Generated Location: (3391:103,0 [15] )
 |ObjectParameter|
 
 Source Location: (19:0,19 [11] x:\dir\subdir\Test\TestComponent.cshtml)
 |MyParameter|
-Generated Location: (3788:120,0 [11] )
+Generated Location: (3645:112,0 [11] )
 |MyParameter|
 

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitStringConversion_BindUnknown/TestComponent.codegen.cs

@@ -17,15 +17,7 @@ public partial class TestComponent : global::Microsoft.AspNetCore.Components.Com
         #pragma warning disable 1998
         protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
         {
-            __builder.OpenComponent<global::Test.
-#nullable restore
-#line (1,2)-(1,13) "x:\dir\subdir\Test\TestComponent.cshtml"
-MyComponent
-
-#line default
-#line hidden
-#nullable disable
-            >(0);
+            __builder.OpenComponent<global::Test.MyComponent>(0);
             __builder.AddAttribute(1, "Value", (object)(
 #nullable restore
 #line (1,27)-(1,28) "x:\dir\subdir\Test\TestComponent.cshtml"

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitStringConversion_BindUnknown/TestComponent.mappings.txt

@@ -1,18 +1,13 @@
-Source Location: (1:0,1 [11] x:\dir\subdir\Test\TestComponent.cshtml)
-|MyComponent|
-Generated Location: (786:22,0 [11] )
-|MyComponent|
-
-Source Location: (26:0,26 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+Source Location: (26:0,26 [1] x:\dir\subdir\Test\TestComponent.cshtml)
 |c|
-Generated Location: (1008:31,0 [1] )
+Generated Location: (861:23,0 [1] )
 |c|
 
 Source Location: (42:2,7 [34] x:\dir\subdir\Test\TestComponent.cshtml)
 |
     private MyClass c = new();
 |
-Generated Location: (1448:43,0 [34] )
+Generated Location: (1301:35,0 [34] )
 |
     private MyClass c = new();
 |

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitStringConversion_BindUnknown_Assignment/TestComponent.codegen.cs

@@ -17,15 +17,7 @@ public partial class TestComponent : global::Microsoft.AspNetCore.Components.Com
         #pragma warning disable 1998
         protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
         {
-            __builder.OpenComponent<global::Test.
-#nullable restore
-#line (1,2)-(1,13) "x:\dir\subdir\Test\TestComponent.cshtml"
-MyComponent
-
-#line default
-#line hidden
-#nullable disable
-            >(0);
+            __builder.OpenComponent<global::Test.MyComponent>(0);
             __builder.AddAttribute(1, "Value", (object)(
 #nullable restore
 #line (1,27)-(1,34) "x:\dir\subdir\Test\TestComponent.cshtml"

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitStringConversion_BindUnknown_Assignment/TestComponent.mappings.txt

@@ -1,19 +1,14 @@
-Source Location: (1:0,1 [11] x:\dir\subdir\Test\TestComponent.cshtml)
-|MyComponent|
-Generated Location: (786:22,0 [11] )
-|MyComponent|
-
-Source Location: (26:0,26 [7] x:\dir\subdir\Test\TestComponent.cshtml)
+Source Location: (26:0,26 [7] x:\dir\subdir\Test\TestComponent.cshtml)
 |c1 = c2|
-Generated Location: (1008:31,0 [7] )
+Generated Location: (861:23,0 [7] )
 |c1 = c2|
 
 Source Location: (48:2,7 [68] x:\dir\subdir\Test\TestComponent.cshtml)
 |
     private MyClass c1 = new();
     private MyClass c2 = new();
 |
-Generated Location: (1466:43,0 [68] )
+Generated Location: (1319:35,0 [68] )
 |
     private MyClass c1 = new();
     private MyClass c2 = new();

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/AddAttribute_ImplicitStringConversion_CustomEvent/TestComponent.codegen.cs

@@ -78,15 +78,7 @@ internal static class TypeInference
     {
         public static void CreateMyComponent_0<T>(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder, int seq, int __seq0, global::Test.MyClass<T> __arg0, int __seq1, global::Microsoft.AspNetCore.Components.EventCallback __arg1, int __seq2, global::System.Boolean __arg2, int __seq3, global::System.String __arg3, int __seq4, global::System.Delegate __arg4, int __seq5, global::System.Object __arg5)
         {
-        __builder.OpenComponent<global::Test.
-#nullable restore
-#line (1,2)-(1,13) "x:\dir\subdir\Test\TestComponent.cshtml"
-MyComponent
-
-#line default
-#line hidden
-#nullable disable
-        <T>>(seq);
+        __builder.OpenComponent<global::Test.MyComponent<T>>(seq);
         __builder.AddAttribute(__seq0, nameof(global::Test.MyComponent<T>.
 #nullable restore
 #line (1,14)-(1,25) "x:\dir\subdir\Test\TestComponent.cshtml"