Merge upstream stable (dlang/dmd@a04cb14657)

Author: kinke

dmd/dmodule.d

@@ -676,6 +676,14 @@ else
             errorSupplemental(loc, "config file: %.*s", cast(int)dmdConfFile.length, dmdConfFile.ptr);
 }
         }
+        else if (FileName.ext(this.arg) || !loc.isValid())
+        {
+            // Modules whose original argument name has an extension, or do not
+            // have a valid location come from the command-line.
+            // Error that their file cannot be found and return early.
+            .error(loc, "cannot find input file `%s`", srcfile.toChars());
+            return false;
+        }
         else
         {
             // if module is not named 'package' but we're trying to read 'package.d', we're looking for a package module

dmd/file_manager.d

@@ -185,11 +185,7 @@ nothrow:
         if (res == 1)
             return readToFileBuffer(name);
 
-        const fullName = lookForSourceFile(name, global.path ? (*global.path)[] : null);
-        if (!fullName)
-            return null;
-
-        return readToFileBuffer(fullName);
+        return null;
     }
 
     extern(C++) FileBuffer* lookup(const(char)* filename)