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Fix issue where we weren't properly adding elastic trivia to newly generated members #79571

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Merged
merged 3 commits into from
Jul 24, 2025
+40 −11
Merged

Fix issue where we weren't properly adding elastic trivia to newly generated members #79571

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c0b76d1
Fix issue where we weren't properly adding elastic trivia to newly ge…
CyrusNajmabadi Jul 24, 2025
210d31a
Fix behavior
CyrusNajmabadi Jul 24, 2025
6e73c9f
Add test
CyrusNajmabadi Jul 24, 2025
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27 changes: 16 additions & 11 deletions src/Workspaces/CSharp/Portable/CodeGeneration/CSharpSyntaxGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -236,9 +236,7 @@ private protected override SyntaxNode MethodDeclaration(

return SyntaxFactory.MethodDeclaration(
attributeLists: default,
// Pass `withLeadingElasticMarker: true` to ensure method will space itself properly within the members it
// is added to.
modifiers: AsModifierList(accessibility, modifiers, SyntaxKind.MethodDeclaration, withLeadingElasticMarker: true),
modifiers: AsModifierList(accessibility, modifiers, SyntaxKind.MethodDeclaration),
returnType: returnType != null ? (TypeSyntax)returnType : SyntaxFactory.PredefinedType(VoidKeyword),
explicitInterfaceSpecifier: null,
identifier: name.ToIdentifierToken(),
Expand Down Expand Up @@ -430,12 +428,13 @@ public override SyntaxNode GetAccessorDeclaration(Accessibility accessibility, I
private protected override SyntaxNode SetAccessorDeclaration(Accessibility accessibility, bool isInitOnly, IEnumerable<SyntaxNode>? statements)
=> AccessorDeclaration(isInitOnly ? SyntaxKind.InitAccessorDeclaration : SyntaxKind.SetAccessorDeclaration, accessibility, statements);

private static SyntaxNode AccessorDeclaration(
private static AccessorDeclarationSyntax AccessorDeclaration(
SyntaxKind kind, Accessibility accessibility, IEnumerable<SyntaxNode>? statements)
{
var accessor = SyntaxFactory.AccessorDeclaration(kind);
accessor = accessor.WithModifiers(
AsModifierList(accessibility, DeclarationModifiers.None, SyntaxKind.PropertyDeclaration));
var accessor = SyntaxFactory
.AccessorDeclaration(kind)
.WithModifiers(
AsModifierList(accessibility, DeclarationModifiers.None, SyntaxKind.PropertyDeclaration));

accessor = statements == null
? accessor.WithSemicolonToken(SemicolonToken)
Expand Down Expand Up @@ -1437,7 +1436,10 @@ public override SyntaxNode WithAccessibility(SyntaxNode declaration, Accessibili
modifiers = modifiers.WithIsStatic(false);
}

var newTokens = Merge(tokens, AsModifierList(accessibility, modifiers));
// We're updating the modifiers for something. We don't want to add elastic trivia in that case as
// we don't want the act of adding/removing/modifying modifiers to change the formatting of the parent
// construct.
var newTokens = Merge(tokens, AsModifierList(accessibility, modifiers, withLeadingElasticMarker: false));
return SetModifierTokens(d, newTokens);
});
}
Expand Down Expand Up @@ -1647,7 +1649,10 @@ private SyntaxNode WithModifiersInternal(SyntaxNode declaration, DeclarationModi
}
}

var newTokens = Merge(tokens, AsModifierList(accessibility, modifiers));
// We're updating the modifiers for something. We don't want to add elastic trivia in that case as
// we don't want the act of adding/removing/modifying modifiers to change the formatting of the parent
// construct.
var newTokens = Merge(tokens, AsModifierList(accessibility, modifiers, withLeadingElasticMarker: false));
return SetModifierTokens(d, newTokens);
});
}
Expand All @@ -1674,13 +1679,13 @@ private static SyntaxTokenList AsModifierList(
Accessibility accessibility,
DeclarationModifiers modifiers,
SyntaxKind kind,
bool withLeadingElasticMarker = false)
bool withLeadingElasticMarker = true)
=> AsModifierList(accessibility, GetAllowedModifiers(kind) & modifiers, withLeadingElasticMarker);

private static SyntaxTokenList AsModifierList(
Accessibility accessibility,
DeclarationModifiers modifiers,
bool withLeadingElasticMarker = false)
bool withLeadingElasticMarker = true)
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@CyrusNajmabadi CyrusNajmabadi Jul 24, 2025

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i have audited all usages of these private functions (so they're only called within this type). In almost all cases we ues this when making a new member. So we want the elastic marker so the new member is placed properly. In the few cases we are just updating a modifieer list, we now explicitly pass in 'false' there.

{
using var _ = ArrayBuilder<SyntaxToken>.GetInstance(out var list);

Expand Down
24 changes: 24 additions & 0 deletions src/Workspaces/CSharpTest/CodeGeneration/SyntaxGeneratorTests.cs
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Expand Up @@ -2916,6 +2916,30 @@ interface i
""");
}

[Fact]
public void TestMultipleMembersIntoClass()
{
using var workspace = new AdhocWorkspace();
var node = Generator.AddMembers(Generator.ClassDeclaration("C"),
[
Generator.MethodDeclaration("M1", returnType: Generator.TypeExpression(SpecialType.System_Void), accessibility: Accessibility.Public),
Generator.PropertyDeclaration("P1", Generator.TypeExpression(SpecialType.System_Int32), accessibility: Accessibility.Public)
]);

AssertEx.EqualOrDiff(
"""
class C
{
public void M1()
{
}

public int P1 { get; set; }
}
""",
Formatter.Format(node, workspace).ToFullString());
}

[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/65932")]
public void TestAddExpressionBodyMembersToInterface()
{
Expand Down
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