Add type definitions for providers()

src/Bicep.Core.IntegrationTests/ScenarioTests.cs

@@ -971,5 +971,33 @@ public void Test_Issue1817()
                 });
             }
         }
+
+        [TestMethod]
+        public void Test_Issue1630()
+        {
+            var (template, diags, _) = CompilationHelper.Compile(@"
+var singleResource = providers('Microsoft.Insights', 'components')
+var allResources = providers('Microsoft.Insights')
+
+// singleResource is an object!
+var firstApiVersion = singleResource.apiVersions[0]
+
+// allResources is an array of objects!
+var firstResourceFirstApiVersion = allResources[0].apiVersions[0]
+
+output singleResource object = singleResource
+output allResources array = allResources
+");
+
+            using (new AssertionScope())
+            {
+                diags.Should().BeEmpty();
+
+                template.Should().HaveValueAtPath("$.variables['singleResource']", "[providers('Microsoft.Insights', 'components')]");
+                template.Should().HaveValueAtPath("$.variables['firstApiVersion']", "[variables('singleResource').apiVersions[0]]");
+                template.Should().HaveValueAtPath("$.variables['allResources']", "[providers('Microsoft.Insights')]");
+                template.Should().HaveValueAtPath("$.variables['firstResourceFirstApiVersion']", "[variables('allResources')[0].apiVersions[0]]");
+            }
+        }
     }
 }

src/Bicep.Core.Samples/Files/Functions/az.json

@@ -117,6 +117,25 @@
       "[offset: int]"
     ]
   },
+  {
+    "name": "providers",
+    "description": "Returns information about a resource provider and its supported resource types. If you don't provide a resource type, the function returns all the supported types for the resource provider.",
+    "fixedParameters": [
+      {
+        "name": "providerNamespace",
+        "description": "the namespace of the provider",
+        "type": "string",
+        "required": true
+      }
+    ],
+    "minimumArgumentCount": 1,
+    "maximumArgumentCount": 1,
+    "flags": "default",
+    "typeSignature": "(providerNamespace: string): provider[]",
+    "parameterTypeSignatures": [
+      "providerNamespace: string"
+    ]
+  },
   {
     "name": "providers",
     "description": "Returns information about a resource provider and its supported resource types. If you don't provide a resource type, the function returns all the supported types for the resource provider.",
@@ -131,16 +150,16 @@
         "name": "resourceType",
         "description": "The type of resource within the specified namespace",
         "type": "string",
-        "required": false
+        "required": true
       }
     ],
-    "minimumArgumentCount": 1,
+    "minimumArgumentCount": 2,
     "maximumArgumentCount": 2,
     "flags": "default",
-    "typeSignature": "(providerNamespace: string, [resourceType: string]): array",
+    "typeSignature": "(providerNamespace: string, resourceType: string): provider",
     "parameterTypeSignatures": [
       "providerNamespace: string",
-      "[resourceType: string]"
+      "resourceType: string"
     ]
   },
   {

src/Bicep.Core.UnitTests/Assertions/JTokenAssertionsExtensions.cs

@@ -69,12 +69,12 @@ public static AndConstraint<JTokenAssertions> HaveValueAtPath(this JTokenAsserti
             Execute.Assertion
                 .BecauseOf(because, becauseArgs)
                 .ForCondition(valueAtPath is not null)
-                .FailWith("Expected value at path {0} to be {1} but it was null", jtokenPath, expected.ToString());
+                .FailWith("Expected value at path {0} to be {1}{reason} but it was null. Original JSON: {2}", jtokenPath, expected.ToString(), instance.Subject?.ToString());
 
             Execute.Assertion
                 .BecauseOf(because, becauseArgs)
                 .ForCondition(JToken.DeepEquals(valueAtPath, expected))
-                .FailWith("Expected value at path {0} to be {1} but it was {2}", jtokenPath, expected.ToString(), valueAtPath?.ToString());
+                .FailWith("Expected value at path {0} to be {1}{reason} but it was {2}", jtokenPath, expected.ToString(), valueAtPath?.ToString());
 
             return new AndConstraint<JTokenAssertions>(instance);
         }
@@ -86,7 +86,7 @@ public static AndConstraint<JTokenAssertions> NotHaveValueAtPath(this JTokenAsse
             Execute.Assertion
                 .BecauseOf(because, becauseArgs)
                 .ForCondition(valueAtPath is null)
-                .FailWith("Expected value at path {0} to be null, but it was {1}", jtokenPath, valueAtPath);
+                .FailWith("Expected value at path {0} to be null{reason}, but it was {1}", jtokenPath, valueAtPath);
 
             return new AndConstraint<JTokenAssertions>(instance);
         }
@@ -96,7 +96,7 @@ public static AndConstraint<JTokenAssertions> NotHaveValue(this JTokenAssertions
             Execute.Assertion
                 .BecauseOf(because, becauseArgs)
                 .ForCondition(instance.Subject is null)
-                .FailWith("Expected value to be null, but it was {0}", instance.Subject?.ToString());
+                .FailWith("Expected value to be null{reason}, but it was {0}", instance.Subject?.ToString());
 
             return new AndConstraint<JTokenAssertions>(instance);
         }

src/Bicep.Core/Semantics/Namespaces/AzNamespaceSymbol.cs

@@ -56,6 +56,17 @@ private static ObjectType GetSubscriptionReturnValue(IEnumerable<FunctionArgumen
                 new TypeProperty("displayName", LanguageConstants.String),
             });
         }
+
+        private static ObjectType GetSingleProvidersReturnValue()
+        {
+            // from https://docs.microsoft.com/en-us/azure/azure-resource-manager/templates/template-functions-resource?tabs=json#providers
+            return new NamedObjectType("provider", TypeSymbolValidationFlags.Default, new []
+            {
+                new TypeProperty("resourceType", LanguageConstants.String),
+                new TypeProperty("locations", new TypedArrayType(LanguageConstants.String, TypeSymbolValidationFlags.Default)),
+                new TypeProperty("apiVersions", new TypedArrayType(LanguageConstants.String, TypeSymbolValidationFlags.Default)),
+            }, null);
+        }
 
         private static NamedObjectType GetEnvironmentReturnType()
         {
@@ -279,12 +290,18 @@ private static IEnumerable<FunctionOverload> GetAzOverloads(ResourceScope resour
                 .WithVariableParameter("resourceName",LanguageConstants.String, minimumCount: 1, "The extension resource name segment")
                 .Build();
 
-            // TODO: Not sure about return type
+            var singleProvider = GetSingleProvidersReturnValue();
             yield return new FunctionOverloadBuilder("providers")
-                .WithReturnType(LanguageConstants.Array)
+                .WithReturnType(new TypedArrayType(singleProvider, TypeSymbolValidationFlags.Default))
+                .WithDescription("Returns information about a resource provider and its supported resource types. If you don't provide a resource type, the function returns all the supported types for the resource provider.")
+                .WithRequiredParameter("providerNamespace",LanguageConstants.String, "the namespace of the provider")
+                .Build();
+
+            yield return new FunctionOverloadBuilder("providers")
+                .WithReturnType(singleProvider)
                 .WithDescription("Returns information about a resource provider and its supported resource types. If you don't provide a resource type, the function returns all the supported types for the resource provider.")
                 .WithRequiredParameter("providerNamespace",LanguageConstants.String, "the namespace of the provider")
-                .WithOptionalParameter("resourceType",LanguageConstants.String, "The type of resource within the specified namespace")
+                .WithRequiredParameter("resourceType",LanguageConstants.String, "The type of resource within the specified namespace")
                 .Build();
 
             // TODO: return type is string[]