diff --git a/src-self-hosted/clang.zig b/src-self-hosted/clang.zig
index 62310e8bea00..546c2fe5278e 100644
--- a/src-self-hosted/clang.zig
+++ b/src-self-hosted/clang.zig
@@ -806,13 +806,13 @@ pub const enum_ZigClangAPValueKind = extern enum {
     ZigClangAPValueAddrLabelDiff,
 };
 pub extern fn ZigClangSourceManager_getSpellingLoc(arg0: ?*const struct_ZigClangSourceManager, Loc: struct_ZigClangSourceLocation) struct_ZigClangSourceLocation;
-pub extern fn ZigClangSourceManager_getFilename(arg0: ?*const struct_ZigClangSourceManager, SpellingLoc: struct_ZigClangSourceLocation) [*c]const u8;
+pub extern fn ZigClangSourceManager_getFilename(self: *const struct_ZigClangSourceManager, SpellingLoc: struct_ZigClangSourceLocation) ?[*]const u8;
 pub extern fn ZigClangSourceManager_getSpellingLineNumber(arg0: ?*const struct_ZigClangSourceManager, Loc: struct_ZigClangSourceLocation) c_uint;
 pub extern fn ZigClangSourceManager_getSpellingColumnNumber(arg0: ?*const struct_ZigClangSourceManager, Loc: struct_ZigClangSourceLocation) c_uint;
 pub extern fn ZigClangSourceManager_getCharacterData(arg0: ?*const struct_ZigClangSourceManager, SL: struct_ZigClangSourceLocation) [*c]const u8;
 pub extern fn ZigClangASTContext_getPointerType(arg0: ?*const struct_ZigClangASTContext, T: struct_ZigClangQualType) struct_ZigClangQualType;
 pub extern fn ZigClangASTUnit_getASTContext(arg0: ?*struct_ZigClangASTUnit) ?*struct_ZigClangASTContext;
-pub extern fn ZigClangASTUnit_getSourceManager(arg0: ?*struct_ZigClangASTUnit) ?*struct_ZigClangSourceManager;
+pub extern fn ZigClangASTUnit_getSourceManager(self: *struct_ZigClangASTUnit) *struct_ZigClangSourceManager;
 pub extern fn ZigClangASTUnit_visitLocalTopLevelDecls(self: *struct_ZigClangASTUnit, context: ?*c_void, Fn: ?extern fn (?*c_void, *const struct_ZigClangDecl) bool) bool;
 pub extern fn ZigClangRecordType_getDecl(record_ty: ?*const struct_ZigClangRecordType) ?*const struct_ZigClangRecordDecl;
 pub extern fn ZigClangEnumType_getDecl(record_ty: ?*const struct_ZigClangEnumType) ?*const struct_ZigClangEnumDecl;
@@ -824,6 +824,7 @@ pub extern fn ZigClangEnumDecl_getDefinition(arg0: ?*const struct_ZigClangEnumDe
 pub extern fn ZigClangRecordDecl_getLocation(arg0: ?*const struct_ZigClangRecordDecl) struct_ZigClangSourceLocation;
 pub extern fn ZigClangEnumDecl_getLocation(arg0: ?*const struct_ZigClangEnumDecl) struct_ZigClangSourceLocation;
 pub extern fn ZigClangTypedefNameDecl_getLocation(arg0: ?*const struct_ZigClangTypedefNameDecl) struct_ZigClangSourceLocation;
+pub extern fn ZigClangDecl_getLocation(self: *const ZigClangDecl) ZigClangSourceLocation;
 pub extern fn ZigClangRecordDecl_isUnion(record_decl: ?*const struct_ZigClangRecordDecl) bool;
 pub extern fn ZigClangRecordDecl_isStruct(record_decl: ?*const struct_ZigClangRecordDecl) bool;
 pub extern fn ZigClangRecordDecl_isAnonymousStructOrUnion(record_decl: ?*const struct_ZigClangRecordDecl) bool;
@@ -833,7 +834,7 @@ pub extern fn ZigClangSourceLocation_eq(a: struct_ZigClangSourceLocation, b: str
 pub extern fn ZigClangTypedefType_getDecl(arg0: ?*const struct_ZigClangTypedefType) ?*const struct_ZigClangTypedefNameDecl;
 pub extern fn ZigClangTypedefNameDecl_getUnderlyingType(arg0: ?*const struct_ZigClangTypedefNameDecl) struct_ZigClangQualType;
 pub extern fn ZigClangQualType_getCanonicalType(arg0: struct_ZigClangQualType) struct_ZigClangQualType;
-pub extern fn ZigClangQualType_getTypePtr(arg0: struct_ZigClangQualType) ?*const struct_ZigClangType;
+pub extern fn ZigClangQualType_getTypePtr(self: struct_ZigClangQualType) *const struct_ZigClangType;
 pub extern fn ZigClangQualType_addConst(arg0: [*c]struct_ZigClangQualType) void;
 pub extern fn ZigClangQualType_eq(arg0: struct_ZigClangQualType, arg1: struct_ZigClangQualType) bool;
 pub extern fn ZigClangQualType_isConstQualified(arg0: struct_ZigClangQualType) bool;
@@ -841,7 +842,7 @@ pub extern fn ZigClangQualType_isVolatileQualified(arg0: struct_ZigClangQualType
 pub extern fn ZigClangQualType_isRestrictQualified(arg0: struct_ZigClangQualType) bool;
 pub extern fn ZigClangType_getTypeClass(self: ?*const struct_ZigClangType) enum_ZigClangTypeClass;
 pub extern fn ZigClangType_isVoidType(self: ?*const struct_ZigClangType) bool;
-pub extern fn ZigClangType_getTypeClassName(self: ?*const struct_ZigClangType) [*c]const u8;
+pub extern fn ZigClangType_getTypeClassName(self: *const struct_ZigClangType) [*]const u8;
 pub extern fn ZigClangStmt_getBeginLoc(self: ?*const struct_ZigClangStmt) struct_ZigClangSourceLocation;
 pub extern fn ZigClangStmt_getStmtClass(self: ?*const struct_ZigClangStmt) enum_ZigClangStmtClass;
 pub extern fn ZigClangStmt_classof_Expr(self: ?*const struct_ZigClangStmt) bool;
@@ -863,6 +864,10 @@ pub extern fn ZigClangAPSInt_getRawData(self: ?*const struct_ZigClangAPSInt) [*c
 pub extern fn ZigClangAPSInt_getNumWords(self: ?*const struct_ZigClangAPSInt) c_uint;
 pub extern fn ZigClangAPValueLValueBase_dyn_cast_Expr(self: struct_ZigClangAPValueLValueBase) ?*const struct_ZigClangExpr;
 pub extern fn ZigClangASTUnit_delete(arg0: ?*struct_ZigClangASTUnit) void;
+
+pub extern fn ZigClangFunctionDecl_getType(self: *const struct_ZigClangFunctionDecl) struct_ZigClangQualType;
+pub extern fn ZigClangFunctionDecl_getLocation(self: *const struct_ZigClangFunctionDecl) struct_ZigClangSourceLocation;
+
 pub const ZigClangSourceLocation = struct_ZigClangSourceLocation;
 pub const ZigClangQualType = struct_ZigClangQualType;
 pub const ZigClangAPValueLValueBase = struct_ZigClangAPValueLValueBase;
@@ -944,6 +949,10 @@ pub const ZigClangStmtClass = enum_ZigClangStmtClass;
 pub const ZigClangCK = enum_ZigClangCK;
 pub const ZigClangAPValueKind = enum_ZigClangAPValueKind;
 
+pub const struct_ZigClangSourceLocation = extern struct {
+    ID: c_uint,
+};
+
 pub const Stage2ErrorMsg = extern struct {
     filename_ptr: ?[*]const u8,
     filename_len: usize,
@@ -968,8 +977,8 @@ pub extern fn ZigClangLoadFromCommandLine(
     resources_path: [*c]const u8,
 ) ?*ZigClangASTUnit;
 
-
 pub extern fn ZigClangDecl_getKind(decl: *const ZigClangDecl) ZigClangDeclKind;
+pub extern fn ZigClangDecl_getDeclKindName(decl: *const struct_ZigClangDecl) [*]const u8;
 
 pub const ZigClangDeclKind = extern enum {
     AccessSpec,
@@ -1047,3 +1056,7 @@ pub const ZigClangDeclKind = extern enum {
     StaticAssert,
     TranslationUnit,
 };
+
+pub const struct_ZigClangQualType = extern struct {
+    ptr: ?*c_void,
+};
diff --git a/src-self-hosted/stage1.zig b/src-self-hosted/stage1.zig
index 7a44e8f3a03b..da2dcb414c7c 100644
--- a/src-self-hosted/stage1.zig
+++ b/src-self-hosted/stage1.zig
@@ -90,7 +90,8 @@ export fn stage2_translate_c(
         .import => translate_c.Mode.import,
         .translate => translate_c.Mode.translate,
     }, &errors, resources_path) catch |err| switch (err) {
-        error.SemanticAnalyzeFail => {
+        // TODO after https://github.com/ziglang/zig/issues/769 we can remove error.UnsupportedType
+        error.SemanticAnalyzeFail, error.UnsupportedType => {
             out_errors_ptr.* = errors.ptr;
             out_errors_len.* = errors.len;
             return Error.CCompileErrors;
diff --git a/src-self-hosted/translate_c.zig b/src-self-hosted/translate_c.zig
index ddf7c6f21da9..7b349764fbe0 100644
--- a/src-self-hosted/translate_c.zig
+++ b/src-self-hosted/translate_c.zig
@@ -13,12 +13,16 @@ pub const Mode = enum {
 
 pub const ClangErrMsg = Stage2ErrorMsg;
 
-pub const Error = error{OutOfMemory};
+pub const Error = error{
+    OutOfMemory,
+    UnsupportedType,
+};
 
 const Context = struct {
     tree: *ast.Tree,
     source_buffer: *std.Buffer,
     err: Error,
+    source_manager: *ZigClangSourceManager,
 
     fn a(c: *Context) *std.mem.Allocator {
         return &c.tree.arena_allocator.allocator;
@@ -28,6 +32,17 @@ const Context = struct {
     fn str(c: *Context, s: [*]const u8) ![]u8 {
         return std.mem.dupe(c.a(), u8, std.mem.toSliceConst(u8, s));
     }
+
+    /// Convert a clang source location to a file:line:column string
+    fn locStr(c: *Context, loc: ZigClangSourceLocation) ![]u8 {
+        const spelling_loc = ZigClangSourceManager_getSpellingLoc(c.source_manager, loc);
+        const filename_c = ZigClangSourceManager_getFilename(c.source_manager, spelling_loc);
+        const filename = if (filename_c) |s| try c.str(s) else ([]const u8)("(no file)");
+
+        const line = ZigClangSourceManager_getSpellingLineNumber(c.source_manager, spelling_loc);
+        const column = ZigClangSourceManager_getSpellingColumnNumber(c.source_manager, spelling_loc);
+        return std.fmt.allocPrint(c.a(), "{}:{}:{}", filename, line, column);
+    }
 };
 
 pub fn translate(
@@ -78,6 +93,7 @@ pub fn translate(
     var context = Context{
         .tree = tree,
         .source_buffer = &source_buffer,
+        .source_manager = ZigClangASTUnit_getSourceManager(ast_unit),
         .err = undefined,
     };
 
@@ -105,27 +121,57 @@ fn declVisitor(c: *Context, decl: *const ZigClangDecl) Error!void {
             return visitFnDecl(c, @ptrCast(*const ZigClangFunctionDecl, decl));
         },
         .Typedef => {
-            try appendToken(c, .LineComment, "// TODO translate typedef");
+            try emitWarning(c, ZigClangDecl_getLocation(decl), "TODO implement translate-c for typedefs");
         },
         .Enum => {
-            try appendToken(c, .LineComment, "// TODO translate enum");
+            try emitWarning(c, ZigClangDecl_getLocation(decl), "TODO implement translate-c for enums");
         },
         .Record => {
-            try appendToken(c, .LineComment, "// TODO translate struct");
+            try emitWarning(c, ZigClangDecl_getLocation(decl), "TODO implement translate-c for structs");
         },
         .Var => {
-            try appendToken(c, .LineComment, "// TODO translate variable");
+            try emitWarning(c, ZigClangDecl_getLocation(decl), "TODO implement translate-c for variables");
         },
         else => {
-            // TODO emit_warning(c, bitcast(decl->getLocation()), "ignoring %s decl", decl->getDeclKindName());
-            try appendToken(c, .LineComment, "// TODO translate unknown decl");
+            const decl_name = try c.str(ZigClangDecl_getDeclKindName(decl));
+            try emitWarning(c, ZigClangDecl_getLocation(decl), "ignoring {} declaration", decl_name);
         },
     }
 }
 
 fn visitFnDecl(c: *Context, fn_decl: *const ZigClangFunctionDecl) Error!void {
     const fn_name = c.str(ZigClangDecl_getName_bytes_begin(@ptrCast(*const ZigClangDecl, fn_decl)));
-    try appendToken(c, .LineComment, "// TODO translate function '{}'", fn_name);
+
+    // TODO The C++ code has this:
+    //if (get_global(c, fn_name)) {
+    //    // we already saw this function
+    //    return;
+    //}
+
+    const fn_decl_loc = ZigClangFunctionDecl_getLocation(fn_decl);
+    const proto_node = transQualType(c, ZigClangFunctionDecl_getType(fn_decl), fn_decl_loc) catch |e| switch (e) {
+        error.UnsupportedType => {
+            try emitWarning(c, fn_decl_loc, "unable to resolve prototype of function '{}'", fn_name);
+            return;
+        },
+        else => return e,
+    };
+
+    try emitWarning(c, fn_decl_loc, "TODO implement translate-c for function decls");
+}
+
+fn transQualType(c: *Context, qt: ZigClangQualType, source_loc: ZigClangSourceLocation) !*ast.Node {
+    return transType(c, ZigClangQualType_getTypePtr(qt), source_loc);
+}
+
+fn transType(c: *Context, ty: *const ZigClangType, source_loc: ZigClangSourceLocation) !*ast.Node {
+    const type_name = c.str(ZigClangType_getTypeClassName(ty));
+    try emitWarning(c, source_loc, "unsupported type: '{}'", type_name);
+    return error.UnsupportedType;
+}
+
+fn emitWarning(c: *Context, loc: ZigClangSourceLocation, comptime format: []const u8, args: ...) !void {
+    try appendToken(c, .LineComment, "// {}: warning: " ++ format, c.locStr(loc), args);
 }
 
 fn appendToken(c: *Context, token_id: Token.Id, comptime format: []const u8, args: ...) !void {
diff --git a/src/translate_c.cpp b/src/translate_c.cpp
index eefdf7e2601b..706d296fc036 100644
--- a/src/translate_c.cpp
+++ b/src/translate_c.cpp
@@ -4009,7 +4009,7 @@ static TransScope *trans_stmt(Context *c, TransScope *scope, const ZigClangStmt
     return child_scope;
 }
 
-static void visit_fn_decl(Context *c, const clang::FunctionDecl *fn_decl) {
+static void visit_fn_decl(Context *c, const ZigClangFunctionDecl *fn_decl) {
     Buf *fn_name = buf_create_from_str(ZigClangDecl_getName_bytes_begin((const ZigClangDecl *)fn_decl));
 
     if (get_global(c, fn_name)) {
@@ -4017,26 +4017,28 @@ static void visit_fn_decl(Context *c, const clang::FunctionDecl *fn_decl) {
         return;
     }
 
-    AstNode *proto_node = trans_qual_type(c, bitcast(fn_decl->getType()), bitcast(fn_decl->getLocation()));
+    AstNode *proto_node = trans_qual_type(c, ZigClangFunctionDecl_getType(fn_decl),
+            ZigClangFunctionDecl_getLocation(fn_decl));
     if (proto_node == nullptr) {
-        emit_warning(c, bitcast(fn_decl->getLocation()), "unable to resolve prototype of function '%s'", buf_ptr(fn_name));
+        emit_warning(c, ZigClangFunctionDecl_getLocation(fn_decl),
+                "unable to resolve prototype of function '%s'", buf_ptr(fn_name));
         return;
     }
 
     proto_node->data.fn_proto.name = fn_name;
-    proto_node->data.fn_proto.is_extern = !fn_decl->hasBody();
+    proto_node->data.fn_proto.is_extern = !((const clang::FunctionDecl*)fn_decl)->hasBody();
 
-    clang::StorageClass sc = fn_decl->getStorageClass();
+    clang::StorageClass sc = ((const clang::FunctionDecl*)fn_decl)->getStorageClass();
     if (sc == clang::SC_None) {
         proto_node->data.fn_proto.visib_mod = c->visib_mod;
-        proto_node->data.fn_proto.is_export = fn_decl->hasBody() ? c->want_export : false;
+        proto_node->data.fn_proto.is_export = ((const clang::FunctionDecl*)fn_decl)->hasBody() ? c->want_export : false;
     } else if (sc == clang::SC_Extern || sc == clang::SC_Static) {
         proto_node->data.fn_proto.visib_mod = c->visib_mod;
     } else if (sc == clang::SC_PrivateExtern) {
-        emit_warning(c, bitcast(fn_decl->getLocation()), "unsupported storage class: private extern");
+        emit_warning(c, ZigClangFunctionDecl_getLocation(fn_decl), "unsupported storage class: private extern");
         return;
     } else {
-        emit_warning(c, bitcast(fn_decl->getLocation()), "unsupported storage class: unknown");
+        emit_warning(c, ZigClangFunctionDecl_getLocation(fn_decl), "unsupported storage class: unknown");
         return;
     }
 
@@ -4044,7 +4046,7 @@ static void visit_fn_decl(Context *c, const clang::FunctionDecl *fn_decl) {
 
     for (size_t i = 0; i < proto_node->data.fn_proto.params.length; i += 1) {
         AstNode *param_node = proto_node->data.fn_proto.params.at(i);
-        const clang::ParmVarDecl *param = fn_decl->getParamDecl(i);
+        const clang::ParmVarDecl *param = ((const clang::FunctionDecl*)fn_decl)->getParamDecl(i);
         const char *name = ZigClangDecl_getName_bytes_begin((const ZigClangDecl *)param);
 
         Buf *proto_param_name;
@@ -4063,7 +4065,7 @@ static void visit_fn_decl(Context *c, const clang::FunctionDecl *fn_decl) {
         param_node->data.param_decl.name = scope_var->zig_name;
     }
 
-    if (!fn_decl->hasBody()) {
+    if (!((const clang::FunctionDecl*)fn_decl)->hasBody()) {
         // just a prototype
         add_top_level_decl(c, proto_node->data.fn_proto.name, proto_node);
         return;
@@ -4071,11 +4073,11 @@ static void visit_fn_decl(Context *c, const clang::FunctionDecl *fn_decl) {
 
     // actual function definition with body
     c->ptr_params.clear();
-    const ZigClangStmt *body = bitcast(fn_decl->getBody());
+    const ZigClangStmt *body = bitcast(((const clang::FunctionDecl*)fn_decl)->getBody());
     AstNode *actual_body_node;
     TransScope *result_scope = trans_stmt(c, scope, body, &actual_body_node);
     if (result_scope == nullptr) {
-        emit_warning(c, bitcast(fn_decl->getLocation()), "unable to translate function");
+        emit_warning(c, ZigClangFunctionDecl_getLocation(fn_decl), "unable to translate function");
         return;
     }
     assert(actual_body_node != nullptr);
@@ -4558,7 +4560,7 @@ static bool decl_visitor(void *context, const ZigClangDecl *decl) {
 
     switch (ZigClangDecl_getKind(decl)) {
         case ZigClangDeclFunction:
-            visit_fn_decl(c, reinterpret_cast<const clang::FunctionDecl*>(decl));
+            visit_fn_decl(c, reinterpret_cast<const ZigClangFunctionDecl*>(decl));
             break;
         case ZigClangDeclTypedef:
             resolve_typedef_decl(c, reinterpret_cast<const ZigClangTypedefNameDecl *>(decl));
diff --git a/src/zig_clang.cpp b/src/zig_clang.cpp
index 17ee80005972..a96ec3aa46fc 100644
--- a/src/zig_clang.cpp
+++ b/src/zig_clang.cpp
@@ -1142,6 +1142,16 @@ ZigClangQualType ZigClangEnumDecl_getIntegerType(const ZigClangEnumDecl *self) {
     return bitcast(reinterpret_cast<const clang::EnumDecl *>(self)->getIntegerType());
 }
 
+struct ZigClangQualType ZigClangFunctionDecl_getType(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    return bitcast(casted->getType());
+}
+
+struct ZigClangSourceLocation ZigClangFunctionDecl_getLocation(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    return bitcast(casted->getLocation());
+}
+
 const ZigClangTypedefNameDecl *ZigClangTypedefType_getDecl(const ZigClangTypedefType *self) {
     auto casted = reinterpret_cast<const clang::TypedefType *>(self);
     const clang::TypedefNameDecl *name_decl = casted->getDecl();
diff --git a/src/zig_clang.h b/src/zig_clang.h
index 777ad8c34bf7..46074fc8402d 100644
--- a/src/zig_clang.h
+++ b/src/zig_clang.h
@@ -599,6 +599,9 @@ ZIG_EXTERN_C struct ZigClangSourceLocation ZigClangEnumDecl_getLocation(const st
 ZIG_EXTERN_C struct ZigClangSourceLocation ZigClangTypedefNameDecl_getLocation(const struct ZigClangTypedefNameDecl *);
 ZIG_EXTERN_C struct ZigClangSourceLocation ZigClangDecl_getLocation(const struct ZigClangDecl *);
 
+ZIG_EXTERN_C struct ZigClangQualType ZigClangFunctionDecl_getType(const struct ZigClangFunctionDecl *);
+ZIG_EXTERN_C struct ZigClangSourceLocation ZigClangFunctionDecl_getLocation(const struct ZigClangFunctionDecl *);
+
 ZIG_EXTERN_C bool ZigClangRecordDecl_isUnion(const struct ZigClangRecordDecl *record_decl);
 ZIG_EXTERN_C bool ZigClangRecordDecl_isStruct(const struct ZigClangRecordDecl *record_decl);
 ZIG_EXTERN_C bool ZigClangRecordDecl_isAnonymousStructOrUnion(const struct ZigClangRecordDecl *record_decl);