Fix static method invocation type inference (PowerShell#8018)

SeeminglyScience · iSazonov · commit 57bf508fec1f · 2018-10-23T16:58:31.000+05:00
Fixes type inference for static method invocations (e.g. [powershell]::Create()).
diff --git a/src/System.Management.Automation/engine/parser/TypeInferenceVisitor.cs b/src/System.Management.Automation/engine/parser/TypeInferenceVisitor.cs
@@ -1603,21 +1603,7 @@ private bool TryGetTypeFromMember(
                     if (methodCacheEntry[0].method.Name.Equals(memberName, StringComparison.OrdinalIgnoreCase))
                     {
                         maybeWantDefaultCtor = false;
-                        if (isInvokeMemberExpressionAst)
-                        {
-                            foreach (var method in methodCacheEntry.methodInformationStructures)
-                            {
-                                if (method.method is MethodInfo methodInfo && !methodInfo.ReturnType.ContainsGenericParameters)
-                                {
-                                    result.Add(new PSTypeName(methodInfo.ReturnType));
-                                }
-                            }
-
-                            return true;
-                        }
-
-                        // Accessing a method as a property, we'd return a wrapper over the method.
-                        result.Add(new PSTypeName(typeof(PSMethod)));
+                        AddTypesFromMethodCacheEntry(methodCacheEntry, result, isInvokeMemberExpressionAst);
                         return true;
                     }
 
@@ -1667,6 +1653,16 @@ private bool TryGetTypeFromMember(
                     ScriptBlock scriptBlock = null;
                     switch (memberInfo)
                     {
+                        case PSMethod m:
+                        {
+                            if (m.adapterData is DotNetAdapter.MethodCacheEntry methodCacheEntry)
+                            {
+                                AddTypesFromMethodCacheEntry(methodCacheEntry, result, isInvokeMemberExpressionAst);
+                                return true;
+                            }
+
+                            return false;
+                        }
                         case PSProperty p:
                         {
                             result.Add(new PSTypeName(p.Value.GetType()));
@@ -1739,6 +1735,28 @@ private bool TryGetTypeFromMember(
             return false;
         }
 
+        private void AddTypesFromMethodCacheEntry(
+            DotNetAdapter.MethodCacheEntry methodCacheEntry,
+            List<PSTypeName> result,
+            bool isInvokeMemberExpressionAst)
+        {
+            if (isInvokeMemberExpressionAst)
+            {
+                foreach (var method in methodCacheEntry.methodInformationStructures)
+                {
+                    if (method.method is MethodInfo methodInfo && !methodInfo.ReturnType.ContainsGenericParameters)
+                    {
+                        result.Add(new PSTypeName(methodInfo.ReturnType));
+                    }
+                }
+
+                return;
+            }
+
+            // Accessing a method as a property, we'd return a wrapper over the method.
+            result.Add(new PSTypeName(typeof(PSMethod)));
+        }
+
         private PSTypeName[] GetExpressionType(ExpressionAst expression, bool isStatic)
         {
             PSTypeName[] exprType;
diff --git a/test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1 b/test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1
@@ -644,6 +644,13 @@ dir -Recurse `
             $res.CompletionMatches | Should -HaveCount 1
             $res.CompletionMatches[0].CompletionText | Should -BeExactly "-LiteralPath"
         }
+
+        It "Test member completion of a static method invocation" {
+            $inputStr = '[powershell]::Create().'
+            $res = TabExpansion2 -inputScript $inputStr -cursorColumn $inputStr.Length
+            $res.CompletionMatches | Should -HaveCount 31
+            $res.CompletionMatches[0].CompletionText | Should -BeExactly "Commands"
+        }
     }
 
     Context "Module completion for 'using module'" {
diff --git a/test/powershell/engine/Api/TypeInference.Tests.ps1 b/test/powershell/engine/Api/TypeInference.Tests.ps1
@@ -242,6 +242,12 @@ Describe "Type inference Tests" -tags "CI" {
         $res.Name | Should -Be 'System.Type'
     }
 
+    It "Infers type from static member method" {
+        $res = [AstTypeInference]::InferTypeOf( { [powershell]::Create() }.Ast)
+        $res.Count | Should -Be 1
+        $res.Name | Should -Be 'System.Management.Automation.PowerShell'
+    }
+
     It "Infers type from integer * stringliteral" {
         $res = [AstTypeInference]::InferTypeOf( {  5 * "5" }.Ast)
         $res.Count | Should -Be 1
@@ -412,7 +418,7 @@ Describe "Type inference Tests" -tags "CI" {
     It "Infers typeof Select-Object when Parameter is ExcludeProperty" {
         $res = [AstTypeInference]::InferTypeOf( {  [io.fileinfo]::new("file")  |  Select-Object -ExcludeProperty *Time*, E* }.Ast)
         $res.Count | Should -Be 1
-        $res[0].Name | Should -Be "System.Management.Automation.PSObject#Attributes:BaseName:Directory:DirectoryName:FullName:IsReadOnly:Length:LinkType:Mode:Name:Target"
+        $res[0].Name | Should -Be "System.Management.Automation.PSObject#Attributes:BaseName:Directory:DirectoryName:FullName:IsReadOnly:Length:LinkType:Mode:Name:Target:VersionInfo"
         $names = $res[0].Members.Name
         $names -contains "BaseName" | Should -BeTrue
         $names -contains "Name" | Should -BeTrue

Original file line number	Diff line number	Diff line change
@@ -644,6 +644,13 @@ dir -Recurse `
`644`	`644`	`$res.CompletionMatches \| Should -HaveCount 1`
`645`	`645`	`$res.CompletionMatches[0].CompletionText \| Should -BeExactly "-LiteralPath"`
`646`	`646`	`}`
	`647`	`+`
	`648`	`+ It "Test member completion of a static method invocation" {`
	`649`	`+ $inputStr = '[powershell]::Create().'`
	`650`	`+ $res = TabExpansion2 -inputScript $inputStr -cursorColumn $inputStr.Length`
	`651`	`+ $res.CompletionMatches \| Should -HaveCount 31`
	`652`	`+ $res.CompletionMatches[0].CompletionText \| Should -BeExactly "Commands"`
	`653`	`+ }`
`647`	`654`	`}`
`648`	`655`
`649`	`656`	`Context "Module completion for 'using module'" {`