wip

Author: ranma42

src/EFCore.Relational/Query/SqlExpressionFactory.cs

@@ -576,7 +576,6 @@ public virtual SqlExpression Coalesce(SqlExpression left, SqlExpression right, R
     {
         var resultType = right.Type;
         var inferredTypeMapping = typeMapping
-            ?? ExpressionExtensions.InferTypeMapping(left, right)
             ?? _typeMappingSource.FindMapping(resultType, Dependencies.Model);
 
         left = ApplyTypeMapping(left, inferredTypeMapping);

test/EFCore.SqlServer.FunctionalTests/Query/NorthwindMiscellaneousQuerySqlServerTest.cs

@@ -2864,7 +2864,7 @@ public override async Task Coalesce_Correct_Type_String(bool async)
 
         AssertSql(
             """
-SELECT COALESCE([c].[Region], N'no region specified')
+SELECT ISNULL(CAST([c].[Region] AS nvarchar(max)), N'no region specified')
 FROM [Customers] AS [c]
 """);
     }
@@ -2875,7 +2875,7 @@ public override async Task Coalesce_Correct_Type_Double(bool async)
 
         AssertSql(
             """
-SELECT COALESCE([e].[ReportsTo], 2.25)
+SELECT ISNULL(CAST([e].[ReportsTo] AS float), 2.25E0)
 FROM [Employees] AS [e]
 """);
     }