fix typo, add more tests for @inline-declaration (JuliaLang#44964)

base/compiler/typeinfer.jl

@@ -838,8 +838,9 @@ function typeinf_edge(interp::AbstractInterpreter, method::Method, @nospecialize
     code = get(code_cache(interp), mi, nothing)
     if code isa CodeInstance # return existing rettype if the code is already inferred
         if code.inferred === nothing && is_stmt_inline(get_curr_ssaflag(caller))
-            # we already inferred this edge previously and decided to discarded the inferred code
-            # but the inlinear will request to use it, we re-infer it here and keep it around in the local cache
+            # we already inferred this edge before and decided to discard the inferred code,
+            # nevertheless we re-infer it here again and keep it around in the local cache
+            # since the inliner will request to use it later
             cache = :local
         else
             effects = ipo_effects(code)

test/compiler/inline.jl

@@ -276,10 +276,14 @@ f34900(x::Int, y::Int) = invoke(f34900, Tuple{Int, Any}, x, y)
 @test fully_eliminated(f34900, Tuple{Int, Int}; retval=Core.Argument(2))
 
 @testset "check jl_ir_flag_inlineable for inline macro" begin
-    @test ccall(:jl_ir_flag_inlineable, Bool, (Any,), first(methods(@inline x -> x)).source)
-    @test !ccall(:jl_ir_flag_inlineable, Bool, (Any,), first(methods( x -> x)).source)
-    @test ccall(:jl_ir_flag_inlineable, Bool, (Any,), first(methods(@inline function f(x) x end)).source)
-    @test !ccall(:jl_ir_flag_inlineable, Bool, (Any,), first(methods(function f(x) x end)).source)
+    @test ccall(:jl_ir_flag_inlineable, Bool, (Any,), only(methods(@inline x -> x)).source)
+    @test ccall(:jl_ir_flag_inlineable, Bool, (Any,), only(methods(x -> (@inline; x))).source)
+    @test !ccall(:jl_ir_flag_inlineable, Bool, (Any,), only(methods(x -> x)).source)
+    @test ccall(:jl_ir_flag_inlineable, Bool, (Any,), only(methods(@inline function f(x) x end)).source)
+    @test ccall(:jl_ir_flag_inlineable, Bool, (Any,), only(methods(function f(x) @inline; x end)).source)
+    @test !ccall(:jl_ir_flag_inlineable, Bool, (Any,), only(methods(function f(x) x end)).source)
+    @test ccall(:jl_ir_flag_inlineable, Bool, (Any,), only(methods() do x @inline; x end).source)
+    @test !ccall(:jl_ir_flag_inlineable, Bool, (Any,), only(methods() do x x end).source)
 end
 
 const _a_global_array = [1]