diff --git a/vyper/cli/vyper_compile.py b/vyper/cli/vyper_compile.py
index 1e24fe64e5..b15c57f296 100755
--- a/vyper/cli/vyper_compile.py
+++ b/vyper/cli/vyper_compile.py
@@ -235,6 +235,7 @@ def compile_files(
 
     contract_sources: ContractCodes = dict()
     for file_name in input_files:
+        file_path = Path(file_name)
         contract_sources[file_path] = input_bundle.load_file(Path(file_path))
 
     storage_layouts = dict()
diff --git a/vyper/cli/vyper_json.py b/vyper/cli/vyper_json.py
index 0bccd62f24..74faa5e612 100755
--- a/vyper/cli/vyper_json.py
+++ b/vyper/cli/vyper_json.py
@@ -170,15 +170,15 @@ def get_compilation_targets(input_dict: dict) -> ContractCodes:
                     f"Calculated keccak of '{path}' does not match keccak given in input JSON"
                 )
         if path in ret:
-            raise JSONError(f"Contract namespace collision: {key}")
+            raise JSONError(f"Contract namespace collision: {path}")
 
-        ret[path] = value["content"]
+        ret[path] = value
 
     for path, value in input_dict.get("interfaces", {}).items():
-        if key in interface_sources:
-            raise JSONError(f"Interface namespace collision: {key}")
+        if path in ret:
+            raise JSONError(f"Interface namespace collision: {path}")
 
-        ret[path] = value
+        ret[path] = {"content": value}
 
     return ret
 
@@ -208,7 +208,7 @@ def get_input_dict_output_formats(input_dict: Dict, contract_sources: ContractCo
         if path == "*":
             output_keys = list(contract_sources.keys())
         else:
-            output_keys = [_standardize_path(path)]
+            output_keys = [Path(path)]
             if output_keys[0] not in contract_sources:
                 raise JSONError(f"outputSelection references unknown contract '{output_keys[0]}'")
 
diff --git a/vyper/compiler/input_bundle.py b/vyper/compiler/input_bundle.py
index 024bde2226..324d4d6564 100644
--- a/vyper/compiler/input_bundle.py
+++ b/vyper/compiler/input_bundle.py
@@ -98,6 +98,7 @@ def _load_from_path(self, path: Path) -> CompilerInput:
         source_id = super()._generate_source_id(path)
         return FileInput(source_id, path, code)
 
+
 # fake filesystem for JSON inputs. takes a base path, and `load_file()`
 # "reads" the file from the JSON input. Note that this input bundle type
 # never actually interacts with the filesystem -- it is guaranteed to be pure!
@@ -107,20 +108,20 @@ class JSONInputBundle(InputBundle):
 
     def _load_from_path(self, path: PurePath) -> CompilerInput:
         try:
-            contents = self.input_json[path]
+            value = self.input_json[path]
         except KeyError:
             raise _NotFound(path)
 
         source_id = super()._generate_source_id(path)
 
-        if isinstance(contents, str):
-            return FileInput(source_id, path, code)
+        if "content" in value:
+            return FileInput(source_id, path, value["content"])
 
-        if "abi" in contents:
-            return ABIInput(source_id, path, contents["abi"])
+        if "abi" in value:
+            return ABIInput(source_id, path, value["abi"])
 
-        if isinstance(contents, list):
-            return ABIInput(source_id, path, contents)
+        if isinstance(value, list):
+            return ABIInput(source_id, path, value)
 
         # TODO: ethPM support
         # if isinstance(contents, dict) and "contractTypes" in contents:
diff --git a/vyper/semantics/analysis/module.py b/vyper/semantics/analysis/module.py
index 597862088e..c2fd9c563a 100644
--- a/vyper/semantics/analysis/module.py
+++ b/vyper/semantics/analysis/module.py
@@ -6,11 +6,10 @@
 
 import vyper.builtins.interfaces
 from vyper import ast as vy_ast
-from vyper.compiler.input_bundle import ABIInput, CompilerInput, InputBundle, VyFile
+from vyper.compiler.input_bundle import InputBundle
 from vyper.evm.opcodes import version_check
 from vyper.exceptions import (
     CallViolation,
-    CompilerPanic,
     ExceptionList,
     InvalidLiteral,
     InvalidType,
@@ -341,8 +340,8 @@ def _load_import(self, level: int, module: str) -> InterfaceT:
         path = _import_to_path(level, module)
         try:
             file = self.input_bundle.load_file(path.with_suffix(".vy"))
-            ast = vy_ast.parse_to_ast(file.source_code, contract_name=file.path)
-            InterfaceT.from_ast(interface_ast)
+            interface_ast = vy_ast.parse_to_ast(file.source_code, contract_name=file.path)
+            return InterfaceT.from_ast(interface_ast)
         except FileNotFoundError:
             file = self.input_bundle.load_file(path.with_suffix(".json"))
             abi = json.loads(file.source_code)