[GrahamTheCoder]

Fixes #1301

Summary

Root cause: DeclarationNodeVisitor.VisitConstructorBlock checks whether a constructor's first statement calls another constructor. It decides this from the member name's text being New: in MyBase.New, New is lexed as an identifier. The check failed in three ways, and in each case the call stayed in the body and came out as base.ctor(...); (CS0117/CS7036):

• Casing: HasMatchingText compared case-sensitively, so MyBase.new(value) and MYBASE.NEW(value) weren't recognised.
• No parentheses: a parameterless call such as MyBase.New has no InvocationExpressionSyntax, so it was never looked at.
• Call keyword: Call MyBase.New(value) is a CallStatementSyntax, not an ExpressionStatementSyntax, so it was never looked at either.

Fix:

• HasMatchingText (CodeConverter/Util/SyntaxTokenExtensions.cs) now compares with OrdinalIgnoreCase:
  • VB keywords are case-insensitive, and the method only takes VB SyntaxKinds.
  • Its only caller is this constructor check, so nothing else is affected.
• A new GetFirstStatementMemberCall (extracted in a pure-refactor commit) finds the called member access and its arguments in the first statement. It accepts:
  • an expression statement or a Call statement,
  • with or without an invocation around the member access, so with or without parentheses.

The same path handles Me.New and MyClass.New, which become : this(...).

Reviewer attention

• I kept the syntactic text check and did not switch to a semantic one (GetSymbolInfo resolving to MethodKind.Constructor):
  • In compiling VB, X.New as a statement is only valid when X is MyBase, Me or MyClass, so the text check is exact.
  • An escaped MyBase.[New](...) is not a constructor call: VB reports BC30456. The check ignores it correctly because the token text includes the brackets.
  • The syntactic check keeps working when semantic info is missing, for example an unresolved base type.
• The first commit on the branch still has its "WIP:" message. I didn't force-push to reword it. Squash-merge would tidy it.

Pre-existing, not fixed

• If a constructor initializer has a ByRef argument that needs a temporary, the output is : base(ref ph<guid>) (CS0103), for any casing.
  • Example: base Sub New(ByRef r As Integer), derived MyBase.New(value + 1) or MyBase.New(SharedProp).
  • Before this PR, non-canonical casing gave base.ctor(...) in that case, so it was broken either way. It needs a separate fix.

Tests

Tests/CSharp/MemberTests/ConstructorTests.cs has 8 new conversion tests. In all of them both the input and the output compile, since the harness reports no errors.

• MyBaseNewWithNonCanonicalCasingAsync: the exact repro from the issue.
• MyBaseNewWithUpperCasingAsync
• MyBaseNewWithoutParenthesesAsync: MyBase.nEw followed by another statement.
• MyBaseNewWithoutParenthesesKeepsCommentAsync: the trailing comment is kept.
• MeAndMyClassNewWithNonCanonicalCasingAsync: Me.new(...) and myclass.NEW(...) become : this(...).
• CallStatementConstructorInitializersWithNonCanonicalCasingAsync: Call MyBase.new(...), call Me.NEW(...) and CALL myclass.New(...).
• MyBaseNewWithNonCanonicalCasingNamedAndOmittedArgumentsAsync: named arguments, and an omitted optional argument.
• FirstStatementNotConstructorCallAsync: Me.Newish(New Base(value)) stays in the body. This is a regression guard and also passes on master.

Tests/TestData/SelfVerifyingTests/VBToCS/InheritanceTests.vb adds the self-verifying test ConstructorInitializersWithNonCanonicalCasing:

• It runs the casing, no-parentheses, Me/MyClass chain and Call forms.
• It asserts which constructors ran and in what order.

Before the fix these tests failed with base.ctor(...) / CS0117. All pass with the fix:

• On master: the casing, no-parentheses and Call conversion tests, and the self-verifying test.
• Before the last commit: the Call tests.

Full suite vs master baseline

• Branch: 1434 passed, 5 skipped, 0 failed (1439).
• Master baseline: 1425 passed, 5 skipped, 0 failed (1430).
• The difference is exactly the 9 new tests. No other changes.

Coverage of changed lines

All changed lines are covered, with all branches taken. Two pre-existing, unchanged branches next to the change are still uncovered:

• IsKindOrHasMatchingText's token.IsKind(NewKeyword) is never true, because Roslyn lexes X.New as an identifier.
• The final else in VisitConstructorBlock, for <other>.New as the first statement, is invalid in VB.

🤖 Generated with Claude Code

https://claude.ai/code/session_019FEr8FVAmHV9bscZ82CChg