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Improve assignment type inference #21143

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Merged
iSazonov merged 7 commits into from
Mar 18, 2025
Merged

Improve assignment type inference #21143

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9b5ac40
Improve assignment type inference
MartinGC94 Jan 26, 2024
9db91de
Merge branch 'PowerShell:master' into ImproveAssignmentInference
MartinGC94 Sep 7, 2024
5983828
Merge branch 'PowerShell:master' into ImproveAssignmentInference
MartinGC94 Feb 19, 2025
9e31c29
Handle attributed assignments
MartinGC94 Feb 19, 2025
1381be1
Merge branch 'PowerShell:master' into ImproveAssignmentInference
MartinGC94 Mar 13, 2025
aa74ecf
Add test
MartinGC94 Mar 13, 2025
c96b4d4
Update src/System.Management.Automation/engine/parser/TypeInferenceVi…
MartinGC94 Mar 14, 2025
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13 changes: 12 additions & 1 deletion src/System.Management.Automation/engine/parser/TypeInferenceVisitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1241,7 +1241,18 @@ object ICustomAstVisitor.VisitDoUntilStatement(DoUntilStatementAst doUntilStatem

object ICustomAstVisitor.VisitAssignmentStatement(AssignmentStatementAst assignmentStatementAst)
{
return assignmentStatementAst.Left.Accept(this);
ExpressionAst child = assignmentStatementAst.Left;
while (child is AttributedExpressionAst attributeChild)
{
if (attributeChild is ConvertExpressionAst convert)
{
return new List<PSTypeName>() { new(convert.Type.TypeName) };
}

child = attributeChild.Child;
}

return assignmentStatementAst.Right.Accept(this);
}

object ICustomAstVisitor.VisitPipeline(PipelineAst pipelineAst)
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20 changes: 20 additions & 0 deletions test/powershell/engine/Api/TypeInference.Tests.ps1
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Expand Up @@ -1469,6 +1469,26 @@ Describe "Type inference Tests" -tags "CI" {
$res.Count | Should -Be 0
}

It 'Infers right side of assignment expression' {
$res = [AstTypeInference]::InferTypeOf( { $Test1 = "Hello" }.Ast.Find({param($ast) $ast -is [Language.AssignmentStatementAst]}, $true))
$res.Count | Should -Be 1
$res.Name | Should -Be "System.String"
}

It 'Infers left side of assignment expression when it is a ConvertExpression' {
$res = [AstTypeInference]::InferTypeOf( { [string]$Test1 = 42 }.Ast.Find({param($ast) $ast -is [Language.AssignmentStatementAst]}, $true))
$res.Count | Should -Be 1
$res.Name | Should -Be "System.String"
}

It 'Infers left side of assignment expression when there is a ConvertExpression among other attributes' {
$res = [AstTypeInference]::InferTypeOf( {
[ValidateLength()] [string] [ValidatePattern()]$Test1 = 42
}.Ast.Find({param($ast) $ast -is [Language.AssignmentStatementAst]}, $true))
$res.Count | Should -Be 1
$res.Name | Should -Be "System.String"
}

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@iSazonov iSazonov Mar 14, 2025

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I don't see tests cases from the PR description:

This will fix the type inference for multiple variable assignments like: $Test1 = [string]$Test2 = $Test3 = $Test4 = 10 and also variables assigned with parentheses: $Test1 = ($Test2 = ls)

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@MartinGC94 MartinGC94 Mar 14, 2025

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That's because the examples from the description are practical examples of where the effect of this change can be felt. However, since the API lets us specify the exact Ast we want to infer, there is no need for the practical examples in the tests as we can make them more specific.

It 'Infers type of all scope variable after variable assignment' {
$res = [AstTypeInference]::InferTypeOf( { $true = "Hello";$true }.Ast)
$res.Count | Should -Be 1
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