Replace NinjaBackend is_rust_target with build.uses_rust

we have two functions to do the exact same thing, and they're basically
implemented the same way. Instead, let's just use the BuildTarget one,
as it's more generally available.

mesonbuild/backend/ninjabackend.py

@@ -691,13 +691,6 @@ int dummy;
         src_block['sources'] += sources
         src_block['generated_sources'] += generated_sources
 
-    def is_rust_target(self, target):
-        if len(target.sources) > 0:
-            first_file = target.sources[0]
-            if first_file.fname.endswith('.rs'):
-                return True
-        return False
-
     def generate_target(self, target):
         try:
             if isinstance(target, build.BuildTarget):
@@ -723,7 +716,7 @@ int dummy;
         if isinstance(target, build.Jar):
             self.generate_jar_target(target)
             return
-        if self.is_rust_target(target):
+        if target.uses_rust():
             self.generate_rust_target(target)
             return
         if 'cs' in target.compilers:

mesonbuild/build.py

@@ -1412,7 +1412,7 @@ You probably should put it in link_with instead.''')
         m = 'Could not get a dynamic linker for build target {!r}'
         raise AssertionError(m.format(self.name))
 
-    def get_using_rustc(self) -> bool:
+    def uses_rust(self) -> bool:
         """Is this target a rust target."""
         return self.sources and self.sources[0].fname.endswith('.rs')
 
@@ -1687,7 +1687,7 @@ class Executable(BuildTarget):
                     self.import_filename = self.gcc_import_filename
 
         if m.is_windows() and ('cs' in self.compilers or
-                               self.get_using_rustc() or
+                               self.uses_rust() or
                                self.get_using_msvc()):
             self.debug_filename = self.name + '.pdb'
 
@@ -1877,7 +1877,7 @@ class SharedLibrary(BuildTarget):
             suffix = 'dll'
             self.vs_import_filename = '{0}{1}.lib'.format(self.prefix if self.prefix is not None else '', self.name)
             self.gcc_import_filename = '{0}{1}.dll.a'.format(self.prefix if self.prefix is not None else 'lib', self.name)
-            if self.get_using_rustc():
+            if self.uses_rust():
                 # Shared library is of the form foo.dll
                 prefix = ''
                 # Import library is called foo.dll.lib

mesonbuild/modules/unstable_rust.py

@@ -85,7 +85,7 @@ class RustModule(ExtensionModule):
         base_target: BuildTarget = unholder(args[1])
         if not isinstance(base_target, BuildTarget):
             raise InterpreterException('Second positional argument to rustmod.test() must be a library or executable')
-        if not base_target.get_using_rustc():
+        if not base_target.uses_rust():
             raise InterpreterException('Second positional argument to rustmod.test() must be a rust based target')
         extra_args = stringlistify(kwargs.get('args', []))