Fix typeinference for assignmentstatements inside ParenExpressions. F…

…ix type inference for variables that have the same name as unrelated parameters
PowerShell · Dec 2, 2022 · c91e29f · c91e29f
1 parent 989134d
commit c91e29f
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Showing 2 changed files with 43 additions and 1 deletion.
diff --git a/src/System.Management.Automation/engine/parser/TypeInferenceVisitor.cs b/src/System.Management.Automation/engine/parser/TypeInferenceVisitor.cs
@@ -609,6 +609,17 @@ object ICustomAstVisitor.VisitScriptBlockExpression(ScriptBlockExpressionAst scr
 
         object ICustomAstVisitor.VisitParenExpression(ParenExpressionAst parenExpressionAst)
         {
+            // AssignmentStatements normally return nothing, but when used inside a ParenExpression it returns the left side of the assignment
+            // For VariableExpressions the right side is used for simplicity, but it doesn't take variable type constraints into consideration
+            if (parenExpressionAst.Pipeline is AssignmentStatementAst assignment)
+            {
+                if (assignment.Left is VariableExpressionAst)
+                {
+                    return assignment.Right.Accept(this);
+                }
+
+                return assignment.Left.Accept(this);
+            }
             return parenExpressionAst.Pipeline.Accept(this);
         }
 
@@ -2468,7 +2479,8 @@ public static bool AstAssignsToSameVariable(this VariableExpressionAst variableA
             if (parameterAst != null)
             {
                 return variableAstVariablePath.IsUnscopedVariable &&
-                       parameterAst.Name.VariablePath.UnqualifiedPath.Equals(variableAstVariablePath.UnqualifiedPath, StringComparison.OrdinalIgnoreCase);
+                       parameterAst.Name.VariablePath.UnqualifiedPath.Equals(variableAstVariablePath.UnqualifiedPath, StringComparison.OrdinalIgnoreCase) &&
+                       parameterAst.Parent.Parent.Extent.EndOffset > variableAst.Extent.StartOffset;
             }
 
             if (ast is ForEachStatementAst foreachAst)

diff --git a/test/powershell/engine/Api/TypeInference.Tests.ps1 b/test/powershell/engine/Api/TypeInference.Tests.ps1
@@ -34,6 +34,11 @@ Describe "Type inference Tests" -tags "CI" {
                 return $script:inferTypeOf4.Invoke($null, @($ast, $powerShell, $runtimePermissions))
             }
         }
+
+        class TypeConstrainedTestClass
+        {
+            [string] $Property1
+        }
     }
 
     It "Infers type from integer" {
@@ -1359,6 +1364,31 @@ Describe "Type inference Tests" -tags "CI" {
         $res = [AstTypeInference]::InferTypeOf( { [string]$TestVar = "";[hashtable]$TestVar = @{};$TestVar }.Ast)
         $res.Name | Should -Be "System.Collections.Hashtable"
     }
+
+    It 'Infers closest variable type and ignores unrelated param blocks' {
+        $res = [AstTypeInference]::InferTypeOf( {
+        [hashtable]$ParameterName=@{}
+        function Verb-Noun {
+            param
+            (
+                [string]$ParameterName
+            )
+        }
+        $ParameterName }.Ast)
+        $res.Name | Should -Be "System.Collections.Hashtable"
+    }
+
+    It 'Infers output from AssignmentStatement inside ParenExpression' {
+        $res = [AstTypeInference]::InferTypeOf( { ($TestVar = "Hello") }.Ast)
+        $res.Name | Should -Be "System.String"
+    }
+
+    It 'Infers output from left side of AssignmentStatement inside ParenExpression when assigning to property' {
+        $res = [AstTypeInference]::InferTypeOf( {
+        $Object = [TypeConstrainedTestClass]@{Property1="Test"}
+        ($Object.Property1 = 2) }.Ast)
+        $res.Name | Should -Be "System.String"
+    }
 }
 
 Describe "AstTypeInference tests" -Tags CI {