C# Language Specification

Invocation expressions and object creation expressions

For an invocation expression expr of the form:

primary-expression ( arg₁ , arg₂ , … , arg_n )

or an object creation expression of the form:

new type ( arg₁ , arg₂ , … , arg_n )

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  For an invocation expression, the definite assignment state of v before primary-expression is the same as the state of v before expr.
  
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  For an invocation expression, the definite assignment state of v before arg₁ is the same as the state of v after primary-expression.
  
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  For an object creation expression, the definite assignment state of v before arg₁ is the same as the state of v before expr.
  
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  For each argument arg_i, the definite assignment state of v after arg_i is determined by the normal expression rules, ignoring any ref or out modifiers.
  
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  For each argument arg_i for any i greater than one, the definite assignment state of v before arg_i is the same as the state of v after arg_i-1.
  
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  If the variable v is passed as an out argument (i.e., an argument of the form “out v”) in any of the arguments, then the state of v after expr is definitely assigned. Otherwise; the state of v after expr is the same as the state of v after arg_n.
  
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  For array initializers (§7.6.10.4), object initializers (§7.6.10.2), collection initializers (§7.6.10.3) and anonymous object initializers (§7.6.10.6), the definite assignment state is determined by the expansion that these constructs are defined in terms of.
  

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