Support full path for -project/-p paramater

src/compiler/diagnosticMessages.json

@@ -1622,7 +1622,7 @@
     },
     "Cannot assign an abstract constructor type to a non-abstract constructor type.": {
         "category": "Error",
-        "code":2517
+        "code": 2517
     },
     "Only an ambient class can be merged with an interface.": {
         "category": "Error",
@@ -2056,6 +2056,14 @@
         "category": "Error",
         "code": 5054
     },
+    "The project file name is not in 'tsconfig(-*).json' format: '{0}'": {
+        "category": "Error",
+        "code": 5055
+    },
+    "Cannot find any project file in specified path: '{0}'": {
+        "category": "Error",
+        "code": 5056
+    },
 
     "Concatenate and emit output to single file.": {
         "category": "Message",

src/compiler/tsc.ts

@@ -180,11 +180,26 @@ namespace ts {
                 reportDiagnostic(createCompilerDiagnostic(Diagnostics.The_current_host_does_not_support_the_0_option, "--project"));
                 return sys.exit(ExitStatus.DiagnosticsPresent_OutputsSkipped);
             }
-            configFileName = normalizePath(combinePaths(commandLine.options.project, "tsconfig.json"));
             if (commandLine.fileNames.length !== 0) {
                 reportDiagnostic(createCompilerDiagnostic(Diagnostics.Option_project_cannot_be_mixed_with_source_files_on_a_command_line));
                 return sys.exit(ExitStatus.DiagnosticsPresent_OutputsSkipped);
             }
+
+            let fileOrDirectory = normalizePath(commandLine.options.project);
+            if (!fileOrDirectory /* current directory */ || sys.directoryExists(fileOrDirectory)) {
+                configFileName = combinePaths(fileOrDirectory, "tsconfig.json");
+            }
+            else {
+                if (!/^tsconfig(?:-.*)?\.json$/.test(getBaseFileName(fileOrDirectory))) {
+                    reportDiagnostic(createCompilerDiagnostic(Diagnostics.The_project_file_name_is_not_in_tsconfig_Asterisk_json_format_Colon_0, commandLine.options.project));
+                    return sys.exit(ExitStatus.DiagnosticsPresent_OutputsSkipped);
+                }
+                configFileName = fileOrDirectory;
+            }
+            if (!sys.fileExists(configFileName)) {
+                reportDiagnostic(createCompilerDiagnostic(Diagnostics.Cannot_find_any_project_file_in_specified_path_Colon_0, commandLine.options.project));
+                return sys.exit(ExitStatus.DiagnosticsPresent_OutputsSkipped);
+            }
         }
         else if (commandLine.fileNames.length === 0 && isJSONSupported()) {
             let searchPath = normalizePath(sys.getCurrentDirectory());