Give C# operators the operand the AST leaves implicit [patch]

[matt-edmondson]

Fixes #126

What changed

In the AST, operators are members, like C++'s Money operator+(Money rhs): the instance is the implicit left-hand operand. C# operators are static and take every operand explicitly. CSharpGenerator wrote the AST's parameters as they were, which caused three problems:

• a binary + with one parameter compiled as unary +, so every a + b call site failed;
• a unary operator or conversion with no parameters failed with CS1019;
• a read-only operator on a struct came out as static readonly, which fails with CS0106. The guard added in Write C# member modifiers only where C# allows them [patch] #225 only checked IsStatic, and an operator is static without the declaration saying so.

Now any operator or conversion that belongs to a type takes that type as a leading self parameter (TakesImplicitOperand). self is the name the C lowering already gives its receiver, so a body that reads self.x means the same thing in both targets. Operators are no longer written readonly.

public static Point operator +(Point self, Point rhs)
public static Point operator -(Point self)
public static implicit operator double(Point self)

Tests

• New CSharpGeneratedSourceCompilesTests.Operators_Compile. It builds CompiledExemplar.Point() with Plus(), Negate() and ToDouble("self.x"), then runs dotnet build on it with a driver that uses a + b, -a and the implicit conversion. If the generator change is reverted, the test fails (CS1534, plus the readonly CS0106 errors).
• Full suite: 1281 passed, 0 failed.

🤖 Generated with Claude Code

https://claude.ai/code/session_01LJsBos8vaJcor3uRqngfwE

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Generated by Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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